Depression is an important problem among diabetic patients. We have investigated the effect of some antidepressant drugs on plasma glucose and insulin levels in normoglycaemic and alloxan‐induced diabetic mice. For this purpose the effects of nortryptiline (as an example of a tricyclic antidepressant) and fluoxetine and sertraline (as examples of selective 5‐HT re‐uptake inhibitors) were examined on plasma glucose and insulin levels.

Nortryptiline significantly increased glucose levels and reduced insulin levels in all animals. Although neither fluoxetine nor sertraline induced changes in insulin levels, both significantly reduced the blood glucose levels of mice.

These results suggest that antidepressive treatment has important risks particularly for diabetics. Tricyclic antidepressants might induce an important decrease in glucose tolerance and worsen the control of diabetic patients. Selective 5‐HT re‐uptake inhibitors, on the other hand, might reduce plasma glucose independently of insulin levels. This point is particularly important and should be remembered when insulin or oral antidiabetic agents are administered to diabetics, because of the possible risk of hypoglycaemia.