Sulphonylureas Rosiglitazone

Rosiglitazone is a thiazolidinedione that can be used in combination with metformin or a sulphonylurea such as gliclazide. Rosiglitazone should be administered with caution in patients with cardiovascular disease. 

Avandia (rosiglitazone) as with other thiazolidinediones is used either as monotherapy or in combination with either metformin or a sulphonylurea. A disadvantage of rosiglitazone is the risk of heart failure as a side-effect. This risk is increased when rosiglitazone is used in patients with cardiovascular disease and when used in combination with insulin. Blood-glucose control may deteriorate temporarily when a thiazolidinedione is substituted for an oral antidiabetic agent. 

Wolffenbuttel BH, Gomis R, Squatrito S, Jones NP, Patwardhan RN. Addition of low-dose rosiglitazone to sulphonylurea therapy improves glycaemic control in Type 2 diabetic patients. Diabet Med 2000 17(l) 40-7. 

No clinically relevant adverse interactions appear to have been reported between the statins and the sulphonylureas. One study reported an increased incidence of adverse effects with repaglinide and simvastatin, the clinical relevance of which is unclear. Most studies have shown no pharmacokinetic interaction or increased incidence of adverse effects when pioglitazone or rosiglitazone were used with atorvastatin or simvastatin. Subcutaneous exenatide modestly decreased the AUC of lovastatin, but no clear pattern of altered efficacy of statins was noted in exenatide clinical trials. 

The more modest increase in AUC of rosiglitazone is less likely to be clinically important, but, until more experience is gained, some caution is warranted. No interaction would be expeeted between trimethoprim and tolbutamide, although note that co-trimoxazole has rarely caused hypogly-caemia alone or combined with various sulphonylureas, see Antidiabetics + Sulfonamides , p.506. 

UK Prospective Diabetes Study (UKPDS) Group (1998) Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). Lancet 352 837-853 Kahn SE, Haffner SM, Heise MA et al (2006) Glycemic durability of rosiglitazone, metformin, or glyburide monotherapy. N Engl J Med 355 2427-2443... 

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