Metformin has also been associated with a reduction in heart and circulatory problems, which makes it the drug of choice for people with Type 2 diabetes, particularly in those who are overweight. Unfortunately, gastrointestinal side effects are a common occurrence in people taking metformin. Problems often include bloating, flatulence, nausea, stomach cramps and diarrhoea. However, these can be minimised by starting on a very low dose, gradually increasing the dose over a number of weeks. Taking metformin with or after food can also help to reduce these effects.
Many people report that the unpleasant side effects start to subside after a few months.
A less common side effect of metformin is a strange metallic taste in the mouth. Metformin should not be used in pregnancy, or in breast-feeding. It should be used with care in the over-65s. It should not be prescribed for anyone with kidney or liver damage, nor for anyone who has recently suffered a heart attack or with severe chest and heart trouble who may have a lower blood oxygen level. Metformin should be avoided in heavy drinkers.