Metformin

💊 What is Metformin used for?

• •The label says it is used, along with diet and exercise, to improve blood sugar (glycemic) control in adults and children aged 10 and older with type 2 diabetes. The label says it is not for people with type 1 diabetes or diabetic ketoacidosis.

How it works

The label says metformin helps the body respond better to the insulin it makes naturally, reduces the amount of sugar the liver makes, and reduces the amount of sugar the intestines absorb. The label says it does not cause the body to make more insulin.

How it is usually taken

• •The label says to swallow the tablets whole and never crush, cut, or chew them. The label says the usual starting schedule is once a day with the evening meal, and the dose may be increased slowly over time based on blood sugar control and how well the medicine is tolerated. Follow the instructions from your prescriber or pharmacist.

Comes as

• •500 mg extended-release tablets: white to off-white, uncoated, capsule-shaped, marked 'G7' on one side

⚠️ Metformin side effects

🛑 Who should not take Metformin, and who should be careful

The label says not to take it if

• 🚨You have severe kidney problems (the label says eGFR below 30 mL/min/1.73 m²).
• 🚨You are allergic to metformin or any ingredient in the tablets.
• 🚨You have acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma.
• 🚨The patient leaflet says not to take it if you have kidney problems.
• 🚨The patient leaflet says that if you are 80 or older, you should not take it unless your kidneys have been checked and are normal.
• 🚨The label says it should not be used for people with type 1 diabetes.

Tell your doctor before taking it if

• •Tell your provider if you have type 1 diabetes or a history of diabetic ketoacidosis, since the label says this medicine should not be used for either.
• •Tell your provider about kidney problems, liver problems, or heart problems, including congestive heart failure.
• •Tell your provider if you are over 80, drink alcohol often, or have episodes of heavy 'binge' drinking.
• •Tell your provider if you take insulin, since the label says combining them may increase the risk of low blood sugar (hypoglycemia).
• •Tell your provider if you are pregnant, plan to become pregnant, or are breastfeeding.
• •Tell your provider about any planned x-ray with injected dye, or planned surgery, because the label says the medicine may need to be stopped for a short time.
• •The label says your blood tests will include regular kidney function checks and periodic checks of vitamin B12 levels.

🔀 Metformin with other medicines, food and alcohol

The label says to discuss these with your doctor or pharmacist

• •Carbonic anhydrase inhibitors such as topiramate, zonisamide, acetazolamide, or dichlorphenamide may increase the risk of lactic acidosis. The label says these may need more frequent monitoring.
• •Drugs that reduce how the kidneys clear metformin, such as ranolazine, vandetanib, dolutegravir, and cimetidine, may increase its effects. The label says benefits and risks should be weighed.
• •Alcohol can increase the effect of metformin on lactate, so the label says to avoid excessive alcohol.
• •Insulin or insulin secretagogues (such as sulfonylureas) may increase the risk of low blood sugar. The label says lower doses of those medicines may be needed.
• •Some medicines can raise blood sugar, such as thiazide and other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, and oral contraceptives. Your pharmacist can give you the full list.

Alcohol and food

The label says excessive alcohol intake, including frequent or heavy binge drinking, raises the risk of lactic acidosis. The label says the usual schedule is with the evening meal.

🤰 Metformin in pregnancy and breastfeeding

Pregnancy

The label says it is not known whether this medicine will harm an unborn baby, and that there is limited data in pregnant women. It also says poorly controlled diabetes during pregnancy carries risks for both mother and baby. If you are pregnant, the label says to talk with your healthcare provider about the best way to control your blood sugar. The label also advises premenopausal women about the possibility of an unintended pregnancy.

Breastfeeding

The label lists breastfeeding as something to tell your healthcare provider about before taking this medicine. The breastfeeding section of the label text provided is cut off, so ask your provider or pharmacist for the full guidance.

🗓️ Storage, missed doses and taking too much

Storage

The label says to store at 20° to 25°C (68° to 77°F), with short excursions allowed between 15° and 30°C (59° to 86°F). It says to dispense in a light-resistant container.

If a dose is missed

The label says not to take two doses on the same day. If a dose is missed, take your usual dose with the next scheduled dose. Ask your pharmacist if you have questions.

If too much is taken

The label says to contact the Poison Help line at 1-800-222-1222 or a medical toxicologist if an overdose is suspected. It notes that overdoses have included amounts greater than 50 grams, with reports of low blood sugar and lactic acidosis. The label says hemodialysis may be useful to remove the medicine from the body.

🗒️ Questions to ask about Metformin

• Is my kidney function healthy enough for this medicine, and how often will it be checked?
• What signs of lactic acidosis should I watch for, and who should I call right away?
• Should I stop this medicine before any x-ray with dye or before surgery, and when can I restart it?
• How much alcohol is too much while I take this medicine?
• Will I need blood tests for vitamin B12 while I take this medicine?
• Could this medicine cause low blood sugar with my other diabetes medicines, such as insulin?
• What should I do if I miss a dose?

❓ Metformin: frequently asked questions