Hesperian Health Guides
Diabetes: Medicines
Contents
Oral Medicines for Type 2 Diabetes
Metformin
Metformin is a diabetes drug that helps the body’s insulin work better and decreases sugar production in the liver. It works well for people with Type 2 diabetes who cannot control their diabetes enough with changes in eating and physical activity but is not used for people with Type 1 diabetes. It is less expensive than other diabetes medicines, will not cause blood sugar to drop too low (hypoglycemia), and does not cause weight gain. Metformin is sometimes given along with other diabetes medications (sulfonylureas or insulin).
Diarrhea, nausea, stomach cramping, gas, and a metallic taste in the mouth. Taking metformin with food will help prevent these side effects. They are usually mild and go away after 1 or 2 weeks after the medicine is started or the dose is increased. If side effects continue, try a lower dose or different medicine.
Someone who is dehydrated or has a severe infection should stop taking metformin until they are better.
- People with kidney problems should have a blood test to check kidney function before starting metformin.
- People with mild kidney disease should be on a low dose of metformin (no more than 1000 mg per day).
- People with severe kidney disease should not take metformin.
People with severe heart problems, liver disease, or who have more than one alcohol drink most days, should not take metformin.
A person with Type 2 diabetes having surgery or x-rays that use dye might be told to stop taking metformin for 1 day before and 2 days after. This is done to prevent a rare but dangerous condition called lactic acidosis.
For anyone taking diabetes medicines, testing a drop of blood to measure blood sugar can show how well the medicine, or a specific dose of the medicine, is working. Usually, a person starts with a low dose and then the dose is increased little by little. So more tests than usual are done when starting a new diabetes drug to help find the dose that works best.
Metformin comes in 500, 850, or 1000 mg tablets, and should be taken with meals.
If blood sugar levels are still high, the dose can be increased starting the following week by using a tablet with more medicine or by taking it more than 1 time a day.
For example:
Take ½ of a 850 mg tablet every night
To take 1000 mg each day, take 500 mg with the morning meal and 500 mg with the evening meal each day
For most adults, metformin works well when they take 1000 to 2000 mg total each day, half with the morning meal and half with the evening meal.
It is also possible to take metformin 3 times a day (with the morning, midday, and evening meals).
For example:
Other medicines that may work
Sulfonylureas and insulin are medicines that are sometimes used instead of or together with metformin.
Sulfonylureas
Sulfonylureas are a varied group of drugs for people with Type 2 diabetes. They help the pancreas make more insulin and help the body use insulin better. Short-acting sulfonylureas lower blood sugar quickly but need to be taken two times each day. Long-acting sulfonylureas work more slowly but last longer in the body, so unless you need a higher dose, it is usually taken 1 time each day.
Sulfonylureas can be used alone or combined with other diabetes medications (metformin or insulin) to better control blood sugar levels. They may become less effective when someone has had Type 2 diabetes for a long time.
Sulfonylureas can make the blood sugar go too low too quickly (see Hypoglycemia), especially if someone does not eat after taking this medicine or is more active than usual. This danger is more likely with long-acting sulfonylureas like glibenclamide (glyburide) and chlorpropamide since they last longer in the body.
- Increased appetite and weight gain are possible side effects. Eating well and getting enough activity can help prevent this.
- Drinking alcohol when using sulfonylureas, especially chlorpropamide, can sometimes cause vomiting.
- For some people, sulfonylureas causes skin rash or increased sensitivity to sun.
People with kidney or liver disease, or who have more than one alcohol drink most days should use sulfonylureas with caution.
For older people (over 65 years old) or people with kidney disease, it is safer to use short-acting sulfonylureas, such as glipizide, and start at the lowest dose, to prevent blood sugars from going too low.
Sulfonylureas cannot be used by people with Type 1 diabetes or by people with allergies to sulfa drugs.
Except for glibenclamide (glyburide), pregnant women should avoid using sulfonylureas unless there is no other diabetes medicine available.
Children with Type 2 diabetes usually are not given sulfonylureas.
Signs of taking too much
The danger signs of low blood sugar include difficulty walking, feeling weak, difficulty seeing, confusion, loss of consciousness, or seizures. If the person is conscious, give them something sweet quickly and a full meal as soon as possible. If unconscious, place a pinch of sugar or honey under his tongue and keep giving small amounts until he wakes up and can eat by himself.
Interactions with other medicines
Other medicines may not work as well when a person is taking sulfonylureas. And if someone is taking insulin, some sulfonylureas may stop being useful for her. Talk to a health worker about all the medicines you are taking.
For anyone taking diabetes medicines, testing a drop of blood to measure blood sugar can show how well the medicine, or a specific dose of the medicine, is working. Usually, a person starts with a low dose and then the dose is increased little by little. So more tests than usual are done when starting a new drug to help find the dose that works best.
Sulfonylureas medicines are used for adults with Type 2 diabetes.
- Take sulfonylureas 30 minutes before you eat. It is important to always eat after you take this medicine because if you are not taking food, your blood sugar could become dangerously low.
- If you are eating well and taking the medicine normally but your blood sugar remains high, talk to your health worker. A change in dose or a different medicine may be needed.
- Sulfonylureas are usually started at the lowest dose and taken 1 time per day before breakfast. The dose is raised very slowly over several weeks if the blood sugar is still high.
Each of the sulfonylurea medicines for adults has different doses. A person starts with a low dose and is tested several days later to see if her blood sugar levels have fallen enough. If she needs a stronger dose, her dose is increased a little.
After another week, she is tested again and the dose is adjusted again, if needed. Too high a dose of sulfonylurea is dangerous, so the dose is changed only a small amount each time.
GLIBENCLAMIDE (GLYBURIDE)
Glibenclamide is a long-acting sulfonylurea and usually comes in 1.25 mg, 2.5 mg, and 5 mg tablets.
If necessary, the dose can be increased. Most people do well with a dose between 2.5 mg and 10 mg each day. If taking 10 mg or more each day, it is common to divide the daily amount in half and take it 2 times a day, once before the morning meal and once before the evening meal.
For example:
GLIMEPIRIDE
Glimepiride is a long-acting sulfonylurea and usually comes in 1 mg, 2 mg, and 4 mg tablets.
If necessary, the dose can be increased. Most people do well with a dose between 1 mg and 4 mg each day, taken 1 time each day. Do not take more than 8 mg in one day.
GLIPIZIDE
Glipizide is a short-acting sulfonylurea and usually comes in 5 mg, and 10 mg tablets.
If necessary, the dose can be increased. Most people do well with a dose between 2.5 mg and 20 mg each day. If taking 10 mg or more each day, it is common to divide the daily amount in half and take it 2 times a day, once before the morning meal and once before the evening meal.
For example:
Do not take more than 20 mg in one day.
GLICLAZIDE and GLICLAZIDE MR
Gliclazide comes in 2 forms.
Regular gliclazide usually comes in 80 mg tablets.
If necessary, the dose can be increased. Most people do well with a dose between 40 mg and 240 mg each day. If taking 160 mg or more per day, then it is common to divide the daily amount in half and take it 2 times a day, once before the morning meal and once before the evening meal.
For example:
Do not take more than 320 mg in one day.
Gliclazide MR (modified release) comes in 30 mg tablets and has a different dose than regular gliclazide. Usually the person starts with 30 mg of gliclazide MR each day.
If necessary, the dose can be increased. Most people do well with a dose between 30 mg and 120 mg each day, 1 time each day, before the morning meal. If using gliclazide MR , do not take more than 120 mg in one day.
CHLORPROPAMIDE
Chlorpropamide is a long-acting sulfonylurea and usually comes in 100 mg and 250 mg tablets.
If necessary, the dose can be increased. Most people do well with a dose between 100 mg and 500 mg each day, 1 time each day, before the morning meal.
Do not take more than 750 mg in one day.
TOLAZAMIDE
Tolazamide is a short-acting sulfonylurea and usually comes in 100 mg, 250 mg, and 500 mg tablets.
If necessary, the dose can be increased. Most people do well with a dose between 100 mg and 1000 mg each day. If taking 500 mg or more each day, it is common to divide the daily amount in half and take it 2 times a day, once before the morning meal and once before the evening meal.
For example:
Do not take more than 1000 mg in one day.
TOLBUTAMIDE
Tolbutamide is a short-acting sulfonylurea and usually comes in 500 mg tablets.
For example:
If necessary, the dose can be increased.
Do not take more than 3000 mg in one day.