Metformin

Medically Reviewed by Dr. Harshi Dhingra, M.D.

Last Reviewed: Nov 10, 2023

Warnings


What are the risks of taking metformin?


Metformin can cause serious health problems, especially in certain high-risk patients. Rarely, Metformin can cause a life-threatening condition called lactic acidosis. The symptoms of lactic acidosis appear quickly and suddenly. You should seek immediate medical care if you experience extreme tiredness, weakness, nausea, vomiting, stomachache, reduced appetite, shortness of breath or rapid, deep breathing, lightheadedness, dizziness, slow or fast heartbeat, skin flushing, feeling cold, and/or muscle pain. The risk of lactic acidosis is higher in people over 65 years of age, those with kidney disease, liver disease, and heart disease, and patients who have had a heart attack, stroke, or diabetic ketoacidosis in the past.

  • The use of certain medications with metformin can increase the risk of lactic acidosis. Be sure to give your health care providers a complete list of medications, including prescription and non-prescription drugs, dietary supplements, vitamins, and herbal products. 

  • Inform your doctor if you have severe diarrhea, vomiting, fever, or serious infections. Also, tell your doctor if you are drinking very little fluid for some reason. Your metformin treatment may need to be temporarily stopped until you recover.

  • Before any surgery or dental procedure, tell your doctors that you take metformin. Also, tell your health care providers if you’re going to have an X-ray procedure involving a dye injection. This is especially true for people who drink large amounts of alcohol and those with liver disease or heart failure history. Your health care providers may need to stop metformin for a few days before and after the imaging.

  • Routine serum Vitamin B12 levels should be measured at two- to three-year intervals as the drug has been observed to cause subnormal B12 levels in certain individuals


What should I tell my doctor before starting metformin (metformin)?

Tell your health care professional about all your medical conditions - Metformin tablets may not be suitable for people with kidney disease and some other medical conditions.

Also, tell your doctor about all your medications, including prescription and over-the-counter medications, dietary supplements, and herbal remedies. This can help avoid serious drug interactions.

Tell your doctor if you drink alcohol on a regular basis. Binge drinking (drinking large amounts of alcohol in a short period) increases the risk of developing lactic acidosis and can lead to a dangerous drop in blood sugar levels. Ask your healthcare provider how much alcohol is safe to drink while on metformin treatment.

Be sure to tell your doctor if you have previously had an allergic reaction to metformin or any of the other ingredients in metformin.

Metformin is safe to take before and during pregnancy and while breastfeeding your baby. Please contact your doctor if you become pregnant while on metformin. Follow your doctor’s instructions on metformin use during pregnancy. Metformin can help control diabetes during pregnancy and prevent the complications of high blood sugar in both mother and baby.

What precautions should I take while on metformin?

Keep all your doctors’ and laboratory appointments. Your health care professional may order certain tests during metformin treatment to check if your kidneys are working well and assess your body’s response to the medicine.

What are metformin interactions?

Taking certain other medications with metformin can affect its efficacy. Drug interactions can also increase the risk of serious side effects and complications such as lactic acidosis. Your physician may choose a different anti-diabetic medication for you or change the dose or frequency of one or both medicines if there are known drug interactions.

Tell your doctor if you are taking the following medications

  • acetazolamide (Diamox)
  • methazolamide 
  • dichlorphenamide (Keveyis)
  • zonisamide (Zonegran)
  • topiramate (Topamax)

This list does not describe all possible metformin interactions. Give your health care provider a complete list of your medications, including prescription drugs, over-the-counter medicines, dietary supplements, and herbal remedies. Also, tell your health care provider if you smoke, drink alcohol, or use illegal drugs because some of these substances can cause serious health complications when used with metformin.