Rosiglitazone and pioglitazone: new preparations. Two new oral antidiabetics both poorly assessed.Prescrire Int. 2002 Dec; 11(62):170-6.PI
(1) Treatment of type 2 (non insulin-dependent) diabetes is based on lifestyle measures and management of cardiovascular risk. (2) The reference first-line drug therapy for type 2 diabetes, when drug therapy is needed, is single-agent treatment with metformin (a biguanide) for overweight patients, or with glibenclamide (a glucose-lowering sulphonylurea) for other patients. (3) If monotherapy fails to control blood glucose levels adequately, most clinical guidelines then recommend a combination of metformin with a glucose-lowering sulphonylurea, although the few available comparative clinical data raise the possibility of excess mortality with this treatment. (4) Rosiglitazone and pioglitazone (glitazones that reduce insulin resistance) have been authorized in the European Union for combination with a glucose-lowering sulphonylurea (for patients in whom metformin is ineffective or poorly tolerated) or with metformin (for obese patients). (5) None of the available trials of rosiglitazone and pioglitazone include data on mortality or morbidity. (6) There are fewer data on pioglitazone than on rosiglitazone. (7) According to short-term comparative trials, rosiglitazone and pioglitazone are more effective than placebo on blood glucose levels. Combinations of rosiglitazone or pioglitazone with metformin or with glucose-lowering sulphonylureas have not been compared with the metformin + glucose-lowering sulphonylurea combination or with insulin. (8) Rosiglitazone and pioglitazone frequently cause weight gain. (9) Pioglitazone has a slightly favourable effect on lipid profiles, unlike rosiglitazone, which increases LDL-cholesterol levels. (10) The main side effect of rosiglitazone and pioglitazone is sodium and water retention, which can provoke oedema, anaemia (by haemodilution), and even heart failure. Rosiglitazone and pioglitazone are also hepatotoxic. (11) Combining rosiglitazone with insulin is contraindicated, owing to the increased risk of heart failure. The same applies to pioglitazone. (12) In practice, neither rosiglitazone nor pioglitazone has a place in the management of type 2 diabetes, except in the context of strictly controlled long-term comparative clinical trials.