30 July 2007

It is still unclear whether rosiglitazone (Avandia) increases the risk of myocardial infarction.

However, the National Prescribing Service Limited (NPS) states that the possibility of a small increase in cardiovascular risk should be borne in mind until further evidence becomes available.

NPS drew this conclusion after reviewing a recent meta-analysis of clinical trials of the drug, which reported that rosiglitazone is responsible for a small but statistically significant increase in the risk of myocardial infarction.

The review and some recommendations around prescribing rosiglitazone are detailed in a fact sheet ‘Rosiglitazone and cardiovascular risk’ available from the NPS website www.nps.org.au/healthpro.

NPS CEO, Lynn Weekes, said it was difficult to draw firm conclusions from the meta-analysis as it had a number of methodological weaknesses.

“Many of the trials included in the meta-analysis were not designed to assess cardiovascular risk and the authors had to rely on summary information posted on a clinical trial register rather than published papers,” she said.

The absolute increase in risk was small (less than 1%). However, the finding of increased risk in the relatively short-term studies included in the meta-analysis raises the possibility that any increased rate of myocardial infarction could be more evident with longer term use.

It is unclear if the potential increase in myocardial infarction risk also applies to the alternative drug in this class, pioglitazone. However the NPS fact sheet states that both rosiglitazone (Avandia) and pioglitazone (Actos) are known to increase the risk of heart failure and reminds prescribers that use of these drugs in people at an increased risk of heart failure should be avoided.

It recommends that rosiglitazone should only be used as either a dual oral therapy in patients with an intolerance or contraindication to metformin or the sulfonylureas, or as a triple oral therapy combined with maximally tolerated doses of metformin and a sulfonylurea.

The NPS recommends that practitioners consider using insulin instead of rosiglitazone in these scenarios.

ENDS

National Prescribing Service Limited (NPS) is an independent, non-profit organisation for Quality Use of Medicines funded by the Australian Government Department of Health and Ageing.