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Metformin Patient Tips

How it works

Metformin improves how our body responds to insulin and decreases absorption of glucose from our intestine. It is used in the treatment of Type 2 diabetes.


  • Metformin is the preferred therapy for people with Type 2 diabetes. May be used in combination with other medications for Type 2 diabetes.
  • May be used in polycystic overay syndrome (off-label); decreases androgen hormone levels, improves menstrual cycles, ovulation and insulin sensitivity.


If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include:

  • Diarrhea, nausea, flatulence, indigestion, headache, lack of energy, taste disturbance.
  • Rarely, can cause lactic acidosis, a condition that can be fatal. Risk is higher in older people or those with other medical conditions.
  • May impair vitamin B12 absorption but rarely results in anemia.
  • Avoid excessive alcohol intake.

Notes: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. For a complete list of all side effects, click here.

Bottom Line

Metformin improves how the body responds to insulin and is effective for the treatment of type 2 diabetes; diarrhea and other stomach-related side effects are common.


  • Take with a meal to reduce the risk of stomach upset. Once daily doses should be taken with the evening meal.
  • Low dosages are usually used initially before being titrated up. Dosages may vary between individuals.
  • Splitting dosages throughout the day (rather than taking as a single dose) may improve gastric side effects such as nausea, diarrhea and indigestion.
  • Swallow slow-release tablets whole; do not crush, break, or chew. Monitoring of blood sugars and other regular laboratory tests are needed.
  • May need to be temporarily discontinued before undergoing investigations requiring contrast media.
  • The outer case of some slow release metformin tablets may be visible in the stools; this does not mean the drug has not been absorbed.
  • Ensure you are educated about the importance of diet and exercise in the management of type 2 diabetes.

Response and Effectiveness

Peak effects seen within 2-3 hours for immediate release forms, or 4 to 8 hours with slow release forms. May take up to 2 weeks of regular dosing for maximum effects to be seen.


Metformin [package insert]. Revised 01/2016 Ingenus Pharmaceuticals, LLC Accessed 03/2016

  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use metformin only for the indication prescribed.

  • Disclaimer: Every effort has been made to ensure that this information is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. This drug information does not endorse drugs, diagnose patients or recommend therapy. It is an informational resource designed as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of this information. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2017 Revision Date: 2016-03-01 00:00:00