Metformin hydrochoride (Glucophage / Glucophage SR)

Metformin hydrochoride (Glucophage / Glucophage SR) is an anti-diabetes drug. It is particularly useful in treating diabetes in patients with insulin resistance and obesity.

Metformin can be taken alone, or if this is not effective, in combination with other drugs such as rosiglitazone (Avandia). Metformin and rosiglitazone are available in a combination tablet called Avandamet, manufactured by GlaxoSmithKline.

The way in which metformin works is uncertain, although it is thought to reduce the body’s rate of glucose production in the liver. It also reduces the rate of glucose absorption from the gut.

Metformin can reduce the insulin resistance that can occur as a side-effect of HIV treatment, notably with protease inhibitors. The drug can also improve perturbations of blood fat and sugar levels that can occur with HIV treatment, particularly by reducing triglyceride levels. These improvements can reduce the chance that a patient will suffer a stroke or heart attack.

Metformin also reduces fat accumulation around the internal organs. However, it can worsen fat loss from under the skin, a more worrying aspect of fat redistribution for most HIV-positive patients.1 2 3 4 5

Side-effects of metformin include diarrhoea, stomach pain, nausea and vomiting. These can be reduced by taking the drug with or after food.

Metformin can also cause elevated levels of lactic acid in the blood, although this is usually only seen in patients with liver, heart or kidney problems. However, lactic acidosis is also a side-effect of some nucleoside reverse transcriptase inhibitors (NRTIs), notably ddI (didanosine, Videx / VidexEC) and d4T (stavudine, Zerit). Patients taking these drugs with metformin may be at an elevated risk of lactic acidosis: one case report has identified this interaction as causing fatal lactic acid elevations.6 For more information on lactic acidosis, see Lactic aidosis.

Metformin does not interact with any currently available protease inhibitors or non-nucleoside reverse transcriptase inhibitors (NNRTIs).


  1. Hadigan C et al. Metformin in the treatment of HIV lipodystrophy syndrome: a randomized controlled trial. JAMA 284: 472-477, 2000
  2. Saint-Marc T et al. Effects of metformin on insulin resistance and central adiposity in patients receiving effective protease inhibitor therapy. AIDS 13: 1000-1002, 1999a
  3. Van Wijk JPH et al. Comparison of rosiglitazone and metformin for treating HIV lipodystrophy: a randomized controlled trial. Ann Intern Med 143: 337-346, 2005
  4. Tomazic J et al. Effect of metformin and rosiglitazone on lipid metabolism in HIV infected patients receiving protease inhibitor containing HAART. Acta Dermatovenerol Alp Panonica Adriat 14: 99-105, 2005
  5. Hadigan C et al. Sustained benefits of metformin therapy on markers of cardiovascular risk in human immunodeficiency virus-infected patients with fat redistribution and insulin resistance. J Clin Endocrinol Metab 87: 4611-4615, 2002
  6. Worth L et al. A cautionary tale: fatal lactic acidosis complicating nucleoside analogue and metformin therapy. Clin Infect Dis 37: 315-316, 2003

Community Consensus Statement on Access to HIV Treatment and its Use for Prevention

Together, we can make it happen

We can end HIV soon if people have equal access to HIV drugs as treatment and as PrEP, and have free choice over whether to take them.

Launched today, the Community Consensus Statement is a basic set of principles aimed at making sure that happens.

The Community Consensus Statement is a joint initiative of AVAC, EATG, MSMGF, GNP+, HIV i-Base, the International HIV/AIDS Alliance, ITPC and NAM/aidsmap

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.

NAM’s information is intended to support, rather than replace, consultation with a healthcare professional. Talk to your doctor or another member of your healthcare team for advice tailored to your situation.