Problems and pitfalls of sulphonylurea therapy in older patients

The prevalence of non-insulin-dependent diabetes mellitus (type II) increases with age, so that approximately half of all known patients in English-speaking countries are over 65 years of age. There is no reason to believe that the criteria for blood glucose control should be any less stringent for elderly patients unless they have a limited life expectancy. Sulphonylurea drugs remain an effective means of achieving blood glucose control after failure of dietary therapy alone in older patients. However, changes in normal metabolism of drugs with age and the development of other pathologies in elderly patients make it important that these drugs are prescribed with care. Severe symptomatic hypoglycaemia is the most serious adverse effect of sulphonylurea drugs and this becomes progressively more likely with increasing age, depending primarily on the substantial reduction of renal function with normal aging. Other adverse effects are much less commonly of clinical importance. To minimise the risk of hypoglycaemia, it is important that patients receive closely supervised dietary management with education about their disease for at least 3 months before sulphonylurea drugs are prescribed. In elderly patients a short-acting agent with no active metabolites should be used. As patients become older, those receiving long-acting agents can be changed to short-acting agents before problems arise. If blood glucose control appears satisfactory on treatment, then symptoms of hypoglycaemia should be sought. If control is poor, then the criteria for introduction of insulin, with appropriate education, do not differ from those in younger patients.