[Drug interactions in diabetic patients]

Many diabetic patients take medications which can interfere with the effect of insulin or oral antidiabetic agents. Glucocorticoid administration is not contraindicated in diabetic subjects, but it usually necessitates a pharmacotherapic adjustment. Most of the other potential diabetogenic drugs do not show evidence of any significant changes in glycaemic control in diabetic individuals; however, their prescription does require appropriate monitoring of blood glucose. Low dose combined oral contraceptives have little or no effect on blood glucose level; however, their prescription is not recommended in diabetic patients because of modifications in haemostasis and lipid metabolism. Oestrogen replacement therapy in post-menopausal women does not reduce glucose tolerance and it may reduce the risk of cardiovascular disease. Drug interactions which induce hypoglycaemia affect mostly non-insulin-dependent diabetic patients who take sulphonylureas. Combined insulin and sulphonylurea therapy is sometimes prescribed in poorly controlled type II diabetes. The efficacy of this combination is modest compared to insulin therapy alone. The influence of human insulin on symptoms and awareness of hypoglycaemia has been debated for several years. Today, the literature survey does not really support the hypothesis that the risk of severe hypoglycaemia is increased after transferring diabetic patients from animal insulin to human insulin. Many medications induce other side effects (e.g. orthostatic hypotension, hyperkaliemia, impotence...) in patients with diabetic complications.