Today I'm going to talk about another diabetes medication in the same class as glyburide. I'd like to introduce you to glipizide, also known by the brand name Glucotrol. This is a 'younger' student in the class (and when I say younger, that is only relative to the 'older' drug glyburide - glyburide was developed in 1966 and glipizide in 1984). If the names are starting to get confusing, that's not a surprise - all of the most common sulfonylureas used today for diabetes start with the letters "gl".
If you want a refresher on sulfonylureas, and the other classes of diabetes medications, you can find out more in my previous post here.
How does it lower blood sugar: Like the other sulfonylureas, glipizide lowers your blood sugar by increasing the amount of insulin that your pancreas puts into your blood. Insulin is put into the blood so that it can "push" sugar into your cells and out of your bloodstream. To a small extent, glipizide may make your cells more sensitive to insulin, but mostly glipizide just increases the amount of available insulin. As I discussed last week, since the pancreas sometimes stops producing insulin as the disease gets worse, glipizide might not always work for you.
The effect on your numbers: Glipizide may lower your A1c by 1-2% (so if your starting A1c was 11, it might go down to 10 or 9 after being on glipizide). Glipizide may cause weight gain.
Dosing: We generally start patients at a dose of 5 mg once daily and then after some time this can be increased, up to a maximum of 40 mg daily. Glipizide also comes in an extended release tablet, which means that the medication will release into your body more slowly. The extended release glipizide cannot be cut, chewed, or crushed.
Just as I mentioned with glyburide, glipizide must be taken with food. If you take glipizide on an empty stomach, your blood sugar will drop and could get dangerously low. If you want to read more about low blood sugar (hypoglycemia) including what it feels like and how to treat it, please visit this link.
Side effects: The major side effects of glipizide are low blood sugar and weight gain. Aside from these, you may have some nausea and diarrhea, which can be avoided by using a lower dosage of glipizide. Some patients may get a rash, itching, and sun sensitivity (sunburning easily) from glipizide. Glipizide does not stay in the body quite as long as glyburide does, so if you had side effects with glyburide, you might not have the same side effects with glipizide.
Who should not take glipizide: If you have a sulfa allergy, you should not take glipizide. If your diet is inconsistent or you have a history of low blood sugar problems, you should probably not take glipizide because of the chance of hypoglycemia. Pregnant and breastfeeding women should not use glipizide. Those with severe liver or kidney failure should also not take glipizide.
Drug interactions: Glipizide will make your body not tolerate alcohol very well, so do not drink alcohol while on glipizide. Side effects of drinking alcohol while on glipizide include nausea, flushing of the skin, vomiting, shortness of breath, and very low blood pressure. But the most important thing that happens is that it can increase the effect of low blood sugar, which can be very dangerous.
Other medications that can interact with glipizide and make it work better or worse are certain blood pressure medications, diuretics (“water pills”), blood thinners, salicylates (like aspirin), and certain antidepressants. Remember, check with your local pharmacist or doctor before starting any new medications, both prescription and over-the-counter. And make sure your pharmacy is aware of all medications that you take so that your pharmacist can check for drug interactions when you come in with a prescription.
Monitoring: You will have to monitor your blood sugars throughout the day. Watch for signs of low blood sugar (feeling like your heart is racing, headache, confusion, increased sweating, hunger, shakiness, tingling in the mouth, and a feeling of anxiety). If you start to feel any of these, check your blood sugar immediately. If it is too low, have a 15 gram carb snack followed soon by a meal of complex carbohydrates.
Place in therapy for diabetes: Glipizide is usually given to a patient when metformin doesn't work fast enough, or if they can't take metformin. Glyburide and glipizide are both about the same price and work the same way, so it is up to your doctor as far as which one you should try first. After some time, your pancreas might stop making insulin, so your doctor will need to choose another medication.
If you want to read more about glipizide, you can learn about it here.
Next week I will discuss the last of the commonly used medications in the class of sulfonylureas. You won't want to miss it!
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As a disclaimer, I am your "virtual" pharmacist, here to provide you with information and answers to questions. However, I am not your local pharmacist and could, in no way, be aware of your specific medical needs. Remember to always check with your medical provider and pharmacist before stopping or starting any new medications. My posts are based on general pharmacy principles and should not considered as your "first opinion" when it comes to your health. Please consult with your doctor and pharmacist about anything regarding your health.
Showing posts with label diabetes drugs. Show all posts
Showing posts with label diabetes drugs. Show all posts
Sunday, September 23, 2012
Sunday, September 16, 2012
Glyburide
So the last time you were at your doctor's office, they told you that you have diabetes and started you on metformin. You went home and started taking it, and tried to improve your diet and exercise. Now you are back in the clinic for your first lab tests. The doctor checks your A1c and it is still not to where it needs to be (less than 7% is the goal). So what do we do? Since so many problems can come from diabetes that is not under control, your doctor is going to want to start you on another medication quickly to bring your numbers down faster.
Which medication will they choose? The American Diabetes Association, as well as other medical organizations, have come up with a "roadmap" of how to treat diabetes using medication. From my blog last week on diabetes, you know that metformin, combined with lifestyle changes in diet and exercise, is our starting point on the journey. If your A1c is not low enough at the next visit, doctors have three main options: insulin, sulfonylureas, or TZDs. If you need a refresher on these categories, or if you are tuning into my blogs for the first time, please read my blog on the different classes of diabetes medications here.
Each option has its own pros and cons, but I'm going to start with the sulfonylureas, since they are the least expensive and most common options, second to metformin. The first sulfonylurea I'll be covering is glyburide, which also goes by brand names DiaBeta, Micronase, and Glynase.
How does it lower blood sugar: Glyburide helps your body release insulin into the blood. Remember, insulin is the hormone in your body that helps take the sugar out of your blood and puts it into your cells. So glyburide puts the insulin where it needs to be - in the blood where your sugars are. In a very small way, glyburide also makes your cells more sensitive to insulin ("opening the door of the cell" for sugar to enter), but this is not the most consistent way that glyburide works. Unfortunately, as type 2 diabetes progresses, the body sometimes can no longer make its own insulin. At that point, glyburide is no longer effective because there is no more insulin there to "move." But in newly diagnosed type 2 diabetics, glyburide can be very effective.
The effect on your numbers: Like metformin, glyburide also lowers your A1c by about 1 - 2% (a patient with an A1c of 9 could go down to an A1c of 8 or 7 when on glyburide). Glyburide really doesn't seem to lower a patient's cholesterol levels, which was a benefit that we saw with metformin.
Dosing: Glyburide is usually taken once daily, in doses from 2.5 to 20 mg. Usually patients are started at 2.5 or 5 mg daily and then increased as needed. Just like with metformin, your doctor can change your dose every 1-2 weeks if needed. Glyburide should always be taken with the first meal of the day (within about 30 minutes before). It is important to always take glyburide with food because otherwise the medication will cause your blood sugar to drop too low (hypoglycemia). So it's important to state again, always take glyburide with food.
Side effects: Hypoglycemia (dangerously low blood sugar) is one of the most dangerous side effects. Weight gain can also be a possibility with glyburide (obviously not ideal in most diabetics). Glyburide is the medication in this class with the most likelihood of these side effects, since it takes the longest to leave your body once it is in there. The other side effects you might have from glyburide are a feeling of stomach fullness (as if you've just finished eating a big meal), heartburn, rashes/itching, and nausea. Very rarely, glyburide can cause liver problems (hepatitis).
Who should not take glyburide: Any patients with a "sulfa" allergy should not take glyburide, or any other sulfonylureas (which I will be covering in the next few weeks), because they contain the thing that you are allergic to. Because of the risk of low blood sugar if not taken correctly, anyone that has a very inconsistent diet or has a history of low blood sugar episodes might not be an ideal candidate for this medicine. Glyburide should not be used in any patient that is pregnant or breastfeeding. Also, if you have severe liver or kidney problems, your doctor will avoid using this class of medications.
Drug interactions: The most important thing that I want to stress here is that alcohol must be avoided when taking glyburide. A simplified way to look at it is that glyburide causes your body to not tolerate alcohol. You could experience side effects such as nausea, flushing of the skin, vomiting, shortness of breath, and very low blood pressure. But the most important thing that happens is that it can increase the effect of low blood sugar, which can be very dangerous. Other medications that can interact with glyburide and make it work better or worse are certain blood pressure medications, diuretics ("water pills"), blood thinners, salicylates (like aspirin), and certain antidepressants. Remember, check with your local pharmacist or doctor before starting any new medications, both prescription and over-the-counter. And make sure your pharmacy is aware of all medications that you take so that your pharmacist can check for drug interactions when you come in with a prescription.
Monitoring: Just like with metformin, your doctor is going to monitor your A1c, and you will need to monitor your blood sugar levels daily. Because of the chance of low blood sugars with this medication, you need to be even more consistent with monitoring your blood sugars, and watching if they are too low. Signs of low blood sugar include feeling like your heart is racing, headache, confusion, increased sweating, hunger, shakiness, tingling in the mouth, and a feeling of anxiety.
If you start to experience any of these, or if you just don't "feel quite right," check your blood sugar immediately. You will need to have a snack available right away to eat that contains at least 15 grams of carbohydrates, in order to raise your blood sugar to a safe level immediately. A list of these types of snacks, as well as other information about hypoglycemia can be found here. I've copied the list over for your reference, to make it easier:
- 4 oz (1/2 cup) of juice or regular soda
- 2 tablespoons of raisins
- 4 or 5 saltine crackers
- 4 teaspoons of sugar
- 1 tablespoon of honey or corn syrup
Choose what will work for you. Read labels and find something that is appropriate for your lifestyle. It needs to be something that is readily accessible by anyone, especially if you are not feeling well enough to get to it. Remember, regular soda is needed here, not diet. When we are trying to raise blood sugar quickly, we need to have sugar, not something that is "diabetes friendly."
Once you've had your 15 grams of carbs, you still need to eat a meal containing complex carbs that will help your body get back up to a normal level. The foods I just mentioned are simple carbohydrates - your body processes them quickly, your blood sugars rise quickly, and then they are gone. Complex carbs are things like vegetables, brown rice, whole grain breads, and wheat pasta. Don't stop with just the 15 gram snack or you might be in the same low blood sugar situation within a few hours.
Place in therapy for diabetes: Glyburide is considered one of the first or second choices for treating type 2 diabetics (second usually to metformin). This is because it is inexpensive, not a shot like insulin is, and only has to be taken once or twice a day. It is important to mention that some patients just don't see any results with glyburide, or the other medications in this class, so we try it and then have to switch to something else. As diabetes progresses and your body changes, sometimes glyburide (and any of the other diabetes medications taken by mouth) does not work as well. About 5-10% of diabetics every year have this happen. If it does, we can sometimes switch you to another medication within the same class. Next week I will be talking about another one within this class, so don't miss it!
In case you are curious and want to know more about glyburide, you can find more information here.
In case you are curious and want to know more about glyburide, you can find more information here.
If this turns out to not be the right drug for you, don't worry. As you will see, we have plenty of options. And as Phil has talked about, you do not have to be a "victim" of diabetes. You can make changes in your own life that will help to fight back the disease. They won't cure it, but they will make our medications much more effective, and will keep you living the healthy and happy life that you deserve. I'm thinking about you, each and every one of you, and wishing you all the best in your fight! Keep up the good work!
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As a disclaimer, I am your "virtual" pharmacist, here to provide you with information and answers to questions. However, I am not your local pharmacist and could, in no way, be aware of your specific medical needs. Remember to always check with your medical provider and pharmacist before stopping or starting any new medications. My posts are based on general pharmacy principles and should not considered as your "first opinion" when it comes to your health. Please consult with your doctor and pharmacist about anything regarding your health.
Saturday, September 8, 2012
Metformin
As I was considering which diabetes drug to feature in my first 'drug post,' there was only one clear choice. The most prescribed medication for diabetes, and one that literally hundreds of my patients use is...metformin! Metformin is the generic name. Some of the brand names you may be familiar with are Glucophage, Glucophage XR, Fortamet, and Riomet (the liquid form of metformin).
Just a heads-up, remember that I am a pharmacist. So, when describing a drug, I will sound like, you guessed it, a pharmacist. Blame my training. I'll try to make things simple and easy to follow and understand, but if I've ever gone too "scientific" and you'd like things explained another way, or you have questions, feel free to let me know. My email will be available at the end of my post. An important thing to remember before I start: glucose is just a fancy name for sugar. I'll probably use glucose because it is most common for me, so just don't be confused by my terminology - I am referring to sugars. So without further ado...metformin!
How does it lower blood sugar: Something for you to remember: as a diabetic you have sugar (glucose) in your blood - kind of floating around your cells because for some reason it's not getting into them. Sugar in the blood and not in the cell is a bad thing. Normally insulin in your body helps sugar enter your cells, but in diabetics it just isn't doing the trick. Metformin makes your cells more sensitive to allowing sugar to enter - kind of like opening the door for sugar. More sugar in cells means less floating around in your blood, which means lower A1c, which makes for a healthier person.
Is that enough? Ok, so now sugar is going into your cells where it belongs, so we have a perfectly wonderful drug for diabetes and can be happy with that. Do you think that the scientists that made metformin thought that? You guessed it, of course they didn't! They wanted more "bang for their buck," so they thought of another way to keep sugars out of your blood. How did they do that? By not allowing it into your blood in the first place. Metformin is very special - it acts as a sort of bodyguard after you eat a meal. Metformin helps to keep some of the sugars that you eat from entering your bloodstream. If the sugars stay in your stomach and intestines and don't enter your blood, the result is lower blood sugar readings. Pretty simple, huh?
But wait, there's more! Would you believe it - your body actually produces it's own sugar! You see, our bodies need a certain amount of sugar for energy. Your brain lives off of it, as do many other important organs. So your liver has the important job of making sugar when needed. Unfortunately in diabetics, it will do this sometimes even when you have enough already in your blood. So for that reason, the makers of metformin decided to develop their drug so that it would stop the liver from producing that extra sugar.
Look at that - three different ways that metformin helps with diabetes! No wonder it is the drug that is chosen first for most new type 2 diabetics.
The effect on your numbers: So where does that put us? How does this change the numbers you are seeing on your blood tests? With metformin, you can expect to see a decrease in your A1c of at least 1-2% (example: your A1c could decrease from 10 down to 8 or 9 after metformin is started). Remember that A1c tells the story of your average blood sugars over the past 3 months. You could look at the blood sugar readings that you take during the day as photographs, whereas your A1c would be the title of the photo album.
An added bonus of metformin is that it might help to lower your bad cholesterol and increase your good cholesterol. There is a potential for modest weight loss when on metformin, but the average is only about 2.6 pounds, so it is not a "miracle" weight loss drug. However, it is unique because it is a diabetes medication that is weight neutral, meaning it does not cause weight gain. As you will learn later, this is not the case with all diabetes medications.
Dosing: Initially, most patients are started at doses of 500 mg once or twice daily of the immediate release (IR) form of metformin. Immediate release just means that the medication enters your blood all at once, versus slowly releasing all day long (extended release). If a patient is new to metformin and is starting at a dose of 500 mg twice daily, I usually recommend starting at 500 mg once daily for the first three days in order to decrease stomach upset. There is a less commonly used 850 mg dose of metformin that is available, which is started at one tablet daily with breakfast.
For some patients, extended release (ER) metformin is chosen. Metformin ER enters the blood more slowly, which leads to less stomach upset and discomfort. Since metformin ER only needs to be taken once daily, it is a good choice for patients that have trouble with taking a medicine twice daily (can't remember, varied schedules, etc). Patients are generally started on 500 - 1000 mg of metformin ER, taken with the evening meal. Do not cut, crush, or chew metformin ER because it is specifically made to disperse throughout the day, not all at once.
Because of unpleasant stomach upset and side effects, metformin should always be taken with food or immediately following the meal. We start metformin at low doses because of the high potential for side effects. Doses are then increased weekly if needed. Generally we do not see a response with metformin at doses less than 1500 mg per day, so don't be discouraged if your doctor keeps increasing your dosage. It may take up to eight weeks of being on metformin before full effectiveness can be seen, so patience really is a virtue.
Side effects: I have already previewed the major side effect of metformin, which is stomach upset. This includes diarrhea, nausea/vomiting, and gas. As I mentioned, taking the medication with meals and increasing doses slowly over days and weeks can help to minimize this. When starting metformin, patients sometimes complain of an unpleasant or metallic taste. This tends to go away within the first few weeks. More rarely we see skin rashes, itching, and sun sensitivity (sunburning easily) with metformin use.
A very rare (2-10 patients per 100,000 patients on metformin per year) but serious side effect that is caused by metformin is something known as lactic acidosis. Lactic acid is a part of our metabolism that helps us produce energy when we do things like exercising. At high levels, it can be very dangerous. Lactic acidosis can be deadly in up to 50% of cases. If lactic acid levels are too high, dialysis is required to remove the metformin from the body and to correct the increased lactic acid levels. Fortunately physicians and pharmacists are well aware of this side effect, and it is easily preventable if certain patients that are more at risk are not given metformin. Side effects from metformin are very rare and can be easily dealt with and prevented by taking the medicine with food and switching to a different medication if needed.
Last week I had a patient that was switched from metformin to glipizide. While her A1c was okay, her kidneys were not doing very well, which could lead to lactic acidosis. So, her doctor changed her to another medication. This leads me into a discussion of which patients would not be eligible to take metformin.
Who should not take metformin: Patients with kidney disease or kidney failure are more at risk of developing lactic acidosis, since metformin is removed from the body solely by the kidneys (if your kidneys are not good, metformin stays in your body too long, causing problems). Your doctor will do blood tests to determine the health of your kidneys prior to starting you on metformin. If your kidneys are not healthy enough, another medication will be used. As we get older, our kidneys generally do not work as well, so metformin is not recommended in anyone over the age of 80 years old, unless your doctor determines that your kidneys are healthy.
The liver is responsible for regulating lactic acid levels in our bodies, so anyone with liver disease should avoid metformin. Since alcohol has a negative effect on the liver, patients should be advised not to drink in excess (binge drinking, or chronic use of more than two drinks per day or at one sitting). I'm sure that the other effects of alcohol on diabetes will be covered in a future blog post.
Drug interactions: Certain stomach medications used for acid reflux (cimetidine - generic for Tagamet, and ranitidine - generic for Zantac) interact with metformin. Two antibiotics (cephalexin - generic for Keflex, and Bactrim) may increase metformin concentrations. You would think that this is a good thing, but it can lead to more harm than good (increased side effects, stomach discomfort and pain). The fluoroquinolone antibiotics (Levaquin, Cipro) may cause increases or decreases in blood glucose levels, which are also not good things for diabetic patients. There are other medications that I have not included on this list, for sake of space, so please remember to check with your pharmacist or physician, and make sure they are aware of all medications you are taking.
I know this is lot of 'pharmese' so far, but I am a pharmacist so what do you expect? Bottom line is that you need to always let your doctor and pharmacist know what drugs you are taking so any negative interactions can be avoided. Don't forget to ask your pharmacist to check for interactions before you stop to pick up a product from the cough/cold or vitamin section of the pharmacy, because these are also medications and they can interact with other things you are taking. Your doctor and pharmacist should be informed about all prescription and over-the-counter medications that you are using, as well as any allergies you have to medications.
Some folks have more than one doctor - always let all doctors know every medication you are on. And, use only one pharmacy so they can check for interactions. You run risks if you use more than one pharmacy - nobody knows all of the drugs you are taking, so you don't have a safeguard in place. So to sum up: make sure all doctors know about all of your medications, and use one pharmacy. Okay? It's best for you that
way. I'll step off my soapbox now.
Monitoring: Sometimes I have patients ask me why they have to make another appointment with their doctor before they will be given any refills. "I'm a diabetic, and I will be for the rest of my life. Why do they need to see me every year? Aren't they just going to keep me on my meds?"
This is a very valid question. As you can see from what I've been talking about in this post, there are many reasons why metformin (or any other medication) might not be appropriate for a patient. And, our bodies are always changing - what might have been the right medication and dosage for you when you started it might not be appropriate six months or even ten years later. Your kidneys and liver might not be working as well to clear the medication. Your control on diabetes might have improved or, sadly enough, gotten worse.
So at least once yearly, your physician will want you to come in for simple blood testing. This will include a serum creatinine (something that gives us an idea of how well your kidneys are functioning), fasting plasma glucose and A1c (remember the photos and photo album?), and other blood components.
The ADA recommends A1c tests twice a year and a full panel of blood tests once a year. Your doctor should be following that as a minimum. In the early stages of treatment, your doctor might test more often to track progress. And, really, how long does a blood test take? Most labs now allow you to make an appointment online so it's faster and more convenient for you. Sometimes you don't even need to see the doctor - you get lab work and they send in the prescription once they have the results. It's as simple as that. But remember, if they do need to see you, please make the appointment. They really are only trying to make sure they have the right medication and dose for you, and that your diabetes is being taken care of properly. We all want you to live a long and happy and enjoyable life.
Place in therapy for diabetes: Metformin is known as the cornerstone for treatment of type 2 diabetes. The current guidelines that we follow when treating new diabetics state that metformin should be started before any other medication, unless the patient is not able to take it for the few reasons I stated earlier. Metformin is also the only medication that is currently approved for use in pre-diabetics to prevent full-blown diabetes. It is also the only oral diabetes medication approved for use in kids (age 10 and up). Since insulin is the only other diabetes medication that can be used in kids right now (and let's face it, what kid wants to get a shot?!), it is a very popular medication for those very young diabetics. Unfortunately it does not work for type 1 diabetes, which is generally diagnosed in younger people.
If you would like to read more about metformin, here is another good website: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000974/
So there you have it, a review of our most popular diabetes medication, metformin. Next week I will move on to one of the different categories of meds that we use to treat high blood sugars, so you will want to stay tuned.
As a disclaimer, I am your "virtual" pharmacist, here to provide you with information and answers to questions. However, I am not your local pharmacist and could, in no way, be aware of your specific medical needs. Remember to always check with your medical provider and pharmacist before stopping or starting any new medications. My posts are based on general pharmacy principles and should not considered as your "first opinion" when it comes to your health. Please consult with your doctor and pharmacist about anything regarding your health.
Please feel free to email me at drk@solutionsfort2diabetes.com if you have any questions on metformin, diabetes medications, or other pharmacy issues. I will attempt to answer all inquiries in a timely manner. Also, if you have a suggestion as to other things you'd like to see me post about, or general pharmacy questions that you think other patients might have, please let me know. Thanks for reading!
Just a heads-up, remember that I am a pharmacist. So, when describing a drug, I will sound like, you guessed it, a pharmacist. Blame my training. I'll try to make things simple and easy to follow and understand, but if I've ever gone too "scientific" and you'd like things explained another way, or you have questions, feel free to let me know. My email will be available at the end of my post. An important thing to remember before I start: glucose is just a fancy name for sugar. I'll probably use glucose because it is most common for me, so just don't be confused by my terminology - I am referring to sugars. So without further ado...metformin!
How does it lower blood sugar: Something for you to remember: as a diabetic you have sugar (glucose) in your blood - kind of floating around your cells because for some reason it's not getting into them. Sugar in the blood and not in the cell is a bad thing. Normally insulin in your body helps sugar enter your cells, but in diabetics it just isn't doing the trick. Metformin makes your cells more sensitive to allowing sugar to enter - kind of like opening the door for sugar. More sugar in cells means less floating around in your blood, which means lower A1c, which makes for a healthier person.
Is that enough? Ok, so now sugar is going into your cells where it belongs, so we have a perfectly wonderful drug for diabetes and can be happy with that. Do you think that the scientists that made metformin thought that? You guessed it, of course they didn't! They wanted more "bang for their buck," so they thought of another way to keep sugars out of your blood. How did they do that? By not allowing it into your blood in the first place. Metformin is very special - it acts as a sort of bodyguard after you eat a meal. Metformin helps to keep some of the sugars that you eat from entering your bloodstream. If the sugars stay in your stomach and intestines and don't enter your blood, the result is lower blood sugar readings. Pretty simple, huh?
But wait, there's more! Would you believe it - your body actually produces it's own sugar! You see, our bodies need a certain amount of sugar for energy. Your brain lives off of it, as do many other important organs. So your liver has the important job of making sugar when needed. Unfortunately in diabetics, it will do this sometimes even when you have enough already in your blood. So for that reason, the makers of metformin decided to develop their drug so that it would stop the liver from producing that extra sugar.
Look at that - three different ways that metformin helps with diabetes! No wonder it is the drug that is chosen first for most new type 2 diabetics.
The effect on your numbers: So where does that put us? How does this change the numbers you are seeing on your blood tests? With metformin, you can expect to see a decrease in your A1c of at least 1-2% (example: your A1c could decrease from 10 down to 8 or 9 after metformin is started). Remember that A1c tells the story of your average blood sugars over the past 3 months. You could look at the blood sugar readings that you take during the day as photographs, whereas your A1c would be the title of the photo album.
An added bonus of metformin is that it might help to lower your bad cholesterol and increase your good cholesterol. There is a potential for modest weight loss when on metformin, but the average is only about 2.6 pounds, so it is not a "miracle" weight loss drug. However, it is unique because it is a diabetes medication that is weight neutral, meaning it does not cause weight gain. As you will learn later, this is not the case with all diabetes medications.
Dosing: Initially, most patients are started at doses of 500 mg once or twice daily of the immediate release (IR) form of metformin. Immediate release just means that the medication enters your blood all at once, versus slowly releasing all day long (extended release). If a patient is new to metformin and is starting at a dose of 500 mg twice daily, I usually recommend starting at 500 mg once daily for the first three days in order to decrease stomach upset. There is a less commonly used 850 mg dose of metformin that is available, which is started at one tablet daily with breakfast.
For some patients, extended release (ER) metformin is chosen. Metformin ER enters the blood more slowly, which leads to less stomach upset and discomfort. Since metformin ER only needs to be taken once daily, it is a good choice for patients that have trouble with taking a medicine twice daily (can't remember, varied schedules, etc). Patients are generally started on 500 - 1000 mg of metformin ER, taken with the evening meal. Do not cut, crush, or chew metformin ER because it is specifically made to disperse throughout the day, not all at once.
Because of unpleasant stomach upset and side effects, metformin should always be taken with food or immediately following the meal. We start metformin at low doses because of the high potential for side effects. Doses are then increased weekly if needed. Generally we do not see a response with metformin at doses less than 1500 mg per day, so don't be discouraged if your doctor keeps increasing your dosage. It may take up to eight weeks of being on metformin before full effectiveness can be seen, so patience really is a virtue.
Side effects: I have already previewed the major side effect of metformin, which is stomach upset. This includes diarrhea, nausea/vomiting, and gas. As I mentioned, taking the medication with meals and increasing doses slowly over days and weeks can help to minimize this. When starting metformin, patients sometimes complain of an unpleasant or metallic taste. This tends to go away within the first few weeks. More rarely we see skin rashes, itching, and sun sensitivity (sunburning easily) with metformin use.
A very rare (2-10 patients per 100,000 patients on metformin per year) but serious side effect that is caused by metformin is something known as lactic acidosis. Lactic acid is a part of our metabolism that helps us produce energy when we do things like exercising. At high levels, it can be very dangerous. Lactic acidosis can be deadly in up to 50% of cases. If lactic acid levels are too high, dialysis is required to remove the metformin from the body and to correct the increased lactic acid levels. Fortunately physicians and pharmacists are well aware of this side effect, and it is easily preventable if certain patients that are more at risk are not given metformin. Side effects from metformin are very rare and can be easily dealt with and prevented by taking the medicine with food and switching to a different medication if needed.
Last week I had a patient that was switched from metformin to glipizide. While her A1c was okay, her kidneys were not doing very well, which could lead to lactic acidosis. So, her doctor changed her to another medication. This leads me into a discussion of which patients would not be eligible to take metformin.
Who should not take metformin: Patients with kidney disease or kidney failure are more at risk of developing lactic acidosis, since metformin is removed from the body solely by the kidneys (if your kidneys are not good, metformin stays in your body too long, causing problems). Your doctor will do blood tests to determine the health of your kidneys prior to starting you on metformin. If your kidneys are not healthy enough, another medication will be used. As we get older, our kidneys generally do not work as well, so metformin is not recommended in anyone over the age of 80 years old, unless your doctor determines that your kidneys are healthy.
The liver is responsible for regulating lactic acid levels in our bodies, so anyone with liver disease should avoid metformin. Since alcohol has a negative effect on the liver, patients should be advised not to drink in excess (binge drinking, or chronic use of more than two drinks per day or at one sitting). I'm sure that the other effects of alcohol on diabetes will be covered in a future blog post.
Drug interactions: Certain stomach medications used for acid reflux (cimetidine - generic for Tagamet, and ranitidine - generic for Zantac) interact with metformin. Two antibiotics (cephalexin - generic for Keflex, and Bactrim) may increase metformin concentrations. You would think that this is a good thing, but it can lead to more harm than good (increased side effects, stomach discomfort and pain). The fluoroquinolone antibiotics (Levaquin, Cipro) may cause increases or decreases in blood glucose levels, which are also not good things for diabetic patients. There are other medications that I have not included on this list, for sake of space, so please remember to check with your pharmacist or physician, and make sure they are aware of all medications you are taking.
I know this is lot of 'pharmese' so far, but I am a pharmacist so what do you expect? Bottom line is that you need to always let your doctor and pharmacist know what drugs you are taking so any negative interactions can be avoided. Don't forget to ask your pharmacist to check for interactions before you stop to pick up a product from the cough/cold or vitamin section of the pharmacy, because these are also medications and they can interact with other things you are taking. Your doctor and pharmacist should be informed about all prescription and over-the-counter medications that you are using, as well as any allergies you have to medications.
Some folks have more than one doctor - always let all doctors know every medication you are on. And, use only one pharmacy so they can check for interactions. You run risks if you use more than one pharmacy - nobody knows all of the drugs you are taking, so you don't have a safeguard in place. So to sum up: make sure all doctors know about all of your medications, and use one pharmacy. Okay? It's best for you that
way. I'll step off my soapbox now.
Monitoring: Sometimes I have patients ask me why they have to make another appointment with their doctor before they will be given any refills. "I'm a diabetic, and I will be for the rest of my life. Why do they need to see me every year? Aren't they just going to keep me on my meds?"
This is a very valid question. As you can see from what I've been talking about in this post, there are many reasons why metformin (or any other medication) might not be appropriate for a patient. And, our bodies are always changing - what might have been the right medication and dosage for you when you started it might not be appropriate six months or even ten years later. Your kidneys and liver might not be working as well to clear the medication. Your control on diabetes might have improved or, sadly enough, gotten worse.
So at least once yearly, your physician will want you to come in for simple blood testing. This will include a serum creatinine (something that gives us an idea of how well your kidneys are functioning), fasting plasma glucose and A1c (remember the photos and photo album?), and other blood components.
The ADA recommends A1c tests twice a year and a full panel of blood tests once a year. Your doctor should be following that as a minimum. In the early stages of treatment, your doctor might test more often to track progress. And, really, how long does a blood test take? Most labs now allow you to make an appointment online so it's faster and more convenient for you. Sometimes you don't even need to see the doctor - you get lab work and they send in the prescription once they have the results. It's as simple as that. But remember, if they do need to see you, please make the appointment. They really are only trying to make sure they have the right medication and dose for you, and that your diabetes is being taken care of properly. We all want you to live a long and happy and enjoyable life.
Place in therapy for diabetes: Metformin is known as the cornerstone for treatment of type 2 diabetes. The current guidelines that we follow when treating new diabetics state that metformin should be started before any other medication, unless the patient is not able to take it for the few reasons I stated earlier. Metformin is also the only medication that is currently approved for use in pre-diabetics to prevent full-blown diabetes. It is also the only oral diabetes medication approved for use in kids (age 10 and up). Since insulin is the only other diabetes medication that can be used in kids right now (and let's face it, what kid wants to get a shot?!), it is a very popular medication for those very young diabetics. Unfortunately it does not work for type 1 diabetes, which is generally diagnosed in younger people.
If you would like to read more about metformin, here is another good website: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000974/
So there you have it, a review of our most popular diabetes medication, metformin. Next week I will move on to one of the different categories of meds that we use to treat high blood sugars, so you will want to stay tuned.
As a disclaimer, I am your "virtual" pharmacist, here to provide you with information and answers to questions. However, I am not your local pharmacist and could, in no way, be aware of your specific medical needs. Remember to always check with your medical provider and pharmacist before stopping or starting any new medications. My posts are based on general pharmacy principles and should not considered as your "first opinion" when it comes to your health. Please consult with your doctor and pharmacist about anything regarding your health.
Please feel free to email me at drk@solutionsfort2diabetes.com if you have any questions on metformin, diabetes medications, or other pharmacy issues. I will attempt to answer all inquiries in a timely manner. Also, if you have a suggestion as to other things you'd like to see me post about, or general pharmacy questions that you think other patients might have, please let me know. Thanks for reading!
Sunday, September 2, 2012
Let's Start at the Very Beginning: Classes of T2 Diabetes Medications
For my first post, I'm going to give a brief overview of the various classes of medications used to treat type 2 diabetes. Within our bodies, blood sugar levels are controlled by various mechanisms. This is a good thing, because it allows us to "attack" diabetes from various angles.
For any of you footbal fans out there, you could compare this to what your favorite coach does. In order to gain yards and score touchdowns, do they always use the same plays for every team they encounter? Of course not! Some plays are more effective against different defensive lines, and all circumstances can change from one snap of the football to the next.
This is the same when it comes to treating diabetes. Every person is unique and has their own body chemistry. This is the same reason why an allergy medication might work well for one person, but not another. Pharmaceutical scientists have studied these differences and have developed a wide variety of drugs to treat the causes of high blood sugar (glucose) at every stage. In future posts I will breakdown each of the currently available type 2 diabetes medications and give you the "need to know" information. But for now, let's start with the basics.
Biguanides
Don't let this name intimidate you. Biguanides, like most other classes of medications, are simply named for the molecule that is part of their chemical structure. In fact, to make things even simpler for you, the biguanide "class" of medications only contains one diabetic medication. One! Metformin, a drug that most type 2 diabetics are very familiar with, is the only biguanide currently available in the US that is used for diabetes.
Biguanides use a few methods for lowering blood glucose levels. The first method is by making the cells of your body more sensitive to insulin. If you are unfamiliar with it, insulin is the hormone made by your pancreas that is responsible for "pushing" glucose into your cells. More glucose in your liver, muscle, and fat tissue = less glucose floating around in the blood. Too much glucose in your blood, and not in your cells, is what causes diabetes. In type 2 diabetics, the body starts to not respond to insulin as well as it should, so metformin helps the cells "recognize" insulin again.
The other way that metformin lowers blood glucose levels is by decreasing the amount of glucose produced by the body. One of my pharmacy professors liked to use the phrase "the liver is a giver." Your liver is responsible for a wide variety of functions, among which is production of glucose. During times of fasting or starvation, the liver does this to prevent dangerous drops in blood glucose. But in diabetics, the extra glucose is not necessary, so metformin stops this.
Another exciting thing about metformin is its ability to produce small decreases in cholesterol. This is something that I will discuss in future posts. As you will see, this is uncommon and part of the reason why metformin is the go-to medication for new diabetics.
Sulfonylureas
Another long name based on a chemical structure. Glyburide, glipizide, and glimepiride are the most well-known students in this class. Compared to the two different mechanisms of action of the biguanides, sulfonylureas do not provide as much "bang for the buck." Their main action comes from the ability to stimulate the pancreas to release more insulin. This causes glucose to enter the cells, decreasing the amount of glucose in the blood.
Meglitinides
This is a category of medications that we see used much less commonly than the two previously mentioned. The two meds in this group are Prandin and Starlix, which are currently only available in their brand name form. Meglitinides are essentially the same as sulfonylureas, except they don't contain a sulfa molecule. This is important for our patients with sulfa allergies. They work the same way as the sulfonylureas (increasing insulin release from the pancreas).
Thiazolidinediones
Sometimes you wonder if we are making these names up, don't you? It's pretty obvious why we abbreviate this class to the term "TZD". The two current TZDs available in the US are Avandia and Actos. The main effect of these medications comes from the ability to sensitize the muscles, liver, and fat tissue to insulin. This allows more glucose to enter the cells and leave the blood stream. They also show some effectiveness in decreasing the amount of glucose that is released by the liver.
Alpha-Glucosidase Inhibitors
This is a newer class of medications that contains the drugs Precose and Glyset. Maybe this shows my "nerdy" side a bit, but I find the mechanism of this class to be quite exciting. Alpha-glucosidase inhibitors work in the small intestine by delaying and preventing complex carbohydrates from being absorbed from what you eat. This means that the carbohydrates don't enter the bloodstream, and your after-meal (postprandial) glucose readings are much lower.
DPP-4 Inhibitors
Januvia, Onglyza, and Trajenta are the current US available medications in this category. These medications cause insulin to be produced and released by the pancreas as blood glucose levels rise. They also decrease the production of glucagon, a hormone that causes the body to break down glucose storage units and dump glucose back into the blood when blood glucose is too low (during periods of fasting or between meals). Finally, DPP-4 inhibitors improve the function of beta cells in the pancreas, which allows them to better produce the insulin that is needed to keep blood glucose levels at normal levels.
Insulin
Most people are familiar with the use of insulin in type 1 diabetics. They require insulin because their bodies are no longer able to produce it. However, insulin is also used as a very effective treatment in type 2 diabetics when oral medications and lifestyle changes are not effective enough at lowering blood glucose.
I have already discussed insulin a bit within the other drug categories, but let's cover it as its own category, to be thorough. At low levels, insulin causes the liver to stop producing glucose. As you increase the insulin dose, that causes the muscles in your body to start taking glucose out of the blood.
Insulin is categorized based on how fast it starts working in the body, and for how long it works (rapid, intermediate, or long acting). In a future post I will discuss the different types of insulins and injection regimens, but for now this is a good place to start.
Incretin Mimetics
The injectible drugs Byetta and Victoza are the two drugs currently within this category. These medications work to lower blood glucose by increasing insulin production in response to high blood glucose levels. They also are unique because they stop glucagon (mentioned earlier) from being released after you eat.
Other ways that incretin mimetics work to lower blood glucose are by improving the function of beta cells in the pancreas (responsible for making insulin) and causing a feeling of fullness (making the patient eat less and lose weight).
Amylin Analogs
Currently the injectible drug Symlin is the only amylin analog. Amylin is a hormone that is released by the body, with insulin, to control glucose levels after you eat. In diabetics, amylin levels are too low. Symlin acts like amylin in the body; it causes glucose to be absorbed into the body more slowly from the food you eat and also makes you feel fuller faster, leading to less calories eaten and more weight loss.
---So there we have it, a basic overview of the many classes of medications available for treating type 2 diabetes. In my next series of posts, I will discuss each medication individually, and give you the most important "need to know" information. As a reminder, every diabetic is different. I will continue to present information in a general format, but always consult with your personal physician and pharmacist before making any changes in your medications. I invite you to feel free to ask me any questions you might have regarding diabetes and medications. Eventually we might have a section of "frequently asked pharmacy questions" in which I answer your questions or address things that I've read about or been asked within my practice recently. I'm here for you, as a part of your virtual care "team." Feel free to help me customize my posts to help your needs.
Dr. K, PharmD
For any of you footbal fans out there, you could compare this to what your favorite coach does. In order to gain yards and score touchdowns, do they always use the same plays for every team they encounter? Of course not! Some plays are more effective against different defensive lines, and all circumstances can change from one snap of the football to the next.
This is the same when it comes to treating diabetes. Every person is unique and has their own body chemistry. This is the same reason why an allergy medication might work well for one person, but not another. Pharmaceutical scientists have studied these differences and have developed a wide variety of drugs to treat the causes of high blood sugar (glucose) at every stage. In future posts I will breakdown each of the currently available type 2 diabetes medications and give you the "need to know" information. But for now, let's start with the basics.
Biguanides
Don't let this name intimidate you. Biguanides, like most other classes of medications, are simply named for the molecule that is part of their chemical structure. In fact, to make things even simpler for you, the biguanide "class" of medications only contains one diabetic medication. One! Metformin, a drug that most type 2 diabetics are very familiar with, is the only biguanide currently available in the US that is used for diabetes.
Biguanides use a few methods for lowering blood glucose levels. The first method is by making the cells of your body more sensitive to insulin. If you are unfamiliar with it, insulin is the hormone made by your pancreas that is responsible for "pushing" glucose into your cells. More glucose in your liver, muscle, and fat tissue = less glucose floating around in the blood. Too much glucose in your blood, and not in your cells, is what causes diabetes. In type 2 diabetics, the body starts to not respond to insulin as well as it should, so metformin helps the cells "recognize" insulin again.
The other way that metformin lowers blood glucose levels is by decreasing the amount of glucose produced by the body. One of my pharmacy professors liked to use the phrase "the liver is a giver." Your liver is responsible for a wide variety of functions, among which is production of glucose. During times of fasting or starvation, the liver does this to prevent dangerous drops in blood glucose. But in diabetics, the extra glucose is not necessary, so metformin stops this.
Another exciting thing about metformin is its ability to produce small decreases in cholesterol. This is something that I will discuss in future posts. As you will see, this is uncommon and part of the reason why metformin is the go-to medication for new diabetics.
Sulfonylureas
Another long name based on a chemical structure. Glyburide, glipizide, and glimepiride are the most well-known students in this class. Compared to the two different mechanisms of action of the biguanides, sulfonylureas do not provide as much "bang for the buck." Their main action comes from the ability to stimulate the pancreas to release more insulin. This causes glucose to enter the cells, decreasing the amount of glucose in the blood.
Meglitinides
This is a category of medications that we see used much less commonly than the two previously mentioned. The two meds in this group are Prandin and Starlix, which are currently only available in their brand name form. Meglitinides are essentially the same as sulfonylureas, except they don't contain a sulfa molecule. This is important for our patients with sulfa allergies. They work the same way as the sulfonylureas (increasing insulin release from the pancreas).
Thiazolidinediones
Sometimes you wonder if we are making these names up, don't you? It's pretty obvious why we abbreviate this class to the term "TZD". The two current TZDs available in the US are Avandia and Actos. The main effect of these medications comes from the ability to sensitize the muscles, liver, and fat tissue to insulin. This allows more glucose to enter the cells and leave the blood stream. They also show some effectiveness in decreasing the amount of glucose that is released by the liver.
Alpha-Glucosidase Inhibitors
This is a newer class of medications that contains the drugs Precose and Glyset. Maybe this shows my "nerdy" side a bit, but I find the mechanism of this class to be quite exciting. Alpha-glucosidase inhibitors work in the small intestine by delaying and preventing complex carbohydrates from being absorbed from what you eat. This means that the carbohydrates don't enter the bloodstream, and your after-meal (postprandial) glucose readings are much lower.
DPP-4 Inhibitors
Januvia, Onglyza, and Trajenta are the current US available medications in this category. These medications cause insulin to be produced and released by the pancreas as blood glucose levels rise. They also decrease the production of glucagon, a hormone that causes the body to break down glucose storage units and dump glucose back into the blood when blood glucose is too low (during periods of fasting or between meals). Finally, DPP-4 inhibitors improve the function of beta cells in the pancreas, which allows them to better produce the insulin that is needed to keep blood glucose levels at normal levels.
Insulin
Most people are familiar with the use of insulin in type 1 diabetics. They require insulin because their bodies are no longer able to produce it. However, insulin is also used as a very effective treatment in type 2 diabetics when oral medications and lifestyle changes are not effective enough at lowering blood glucose.
I have already discussed insulin a bit within the other drug categories, but let's cover it as its own category, to be thorough. At low levels, insulin causes the liver to stop producing glucose. As you increase the insulin dose, that causes the muscles in your body to start taking glucose out of the blood.
Insulin is categorized based on how fast it starts working in the body, and for how long it works (rapid, intermediate, or long acting). In a future post I will discuss the different types of insulins and injection regimens, but for now this is a good place to start.
Incretin Mimetics
The injectible drugs Byetta and Victoza are the two drugs currently within this category. These medications work to lower blood glucose by increasing insulin production in response to high blood glucose levels. They also are unique because they stop glucagon (mentioned earlier) from being released after you eat.
Other ways that incretin mimetics work to lower blood glucose are by improving the function of beta cells in the pancreas (responsible for making insulin) and causing a feeling of fullness (making the patient eat less and lose weight).
Amylin Analogs
Currently the injectible drug Symlin is the only amylin analog. Amylin is a hormone that is released by the body, with insulin, to control glucose levels after you eat. In diabetics, amylin levels are too low. Symlin acts like amylin in the body; it causes glucose to be absorbed into the body more slowly from the food you eat and also makes you feel fuller faster, leading to less calories eaten and more weight loss.
---So there we have it, a basic overview of the many classes of medications available for treating type 2 diabetes. In my next series of posts, I will discuss each medication individually, and give you the most important "need to know" information. As a reminder, every diabetic is different. I will continue to present information in a general format, but always consult with your personal physician and pharmacist before making any changes in your medications. I invite you to feel free to ask me any questions you might have regarding diabetes and medications. Eventually we might have a section of "frequently asked pharmacy questions" in which I answer your questions or address things that I've read about or been asked within my practice recently. I'm here for you, as a part of your virtual care "team." Feel free to help me customize my posts to help your needs.
Dr. K, PharmD
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