Rosiglitazone (Avandia, Avandamet ) and Pioglitazone ( Actos, Competact ) are treatments for patients with type 2 diabetes and belong to a class of drugs called thiazolidinediones ( also called glitazones ).

Concerns have arisen about the cardiovascular safety of thiazolidinediones: heart failure is a recognised risk, and more recently analyses have suggested that Rosiglitazone might be associated with a small increased risk of myocardial infarction.

These concerns have led to a Europe-wide review of available data for the safety and efficacy of thiazolidinediones, including cardiovascular safety.

Revised prescribing information emphasises that the benefits of Rosiglitazone and Pioglitazone for treatment of type 2 diabetes continue to outweigh the risks.
However, the prescribing information will be updated to include a warning that Rosiglitazone should be used in patients with ischaemic heart disease only after careful evaluation of every patient¡¦s individual risk.
Furthermore, Rosiglitazone combined with Insulin should be used only in exceptional cases and under close supervision.

Fluid retention and cardiac failure

Rosiglitazone and Pioglitazone can cause fluid retention, which may exacerbate or precipitate heart failure. Patients at particular risk are: those who receive concurrent Insulin or sulphonylurea; those at risk of heart failure ( eg, previous myocardial infarction or symptomatic coronary artery disease ); and those with reduced cardiac reserve.

Myocardial ischaemia

A meta-analysis of data from clinical trials showed that the overall incidence of cardiac ischaemic events was higher for rosiglitazone than for comparators ( 1.99% vs 1.51%; hazard ratio 1.31 ); however, there was no increase in overall mortality.
The risk of cardiac ischaemic events seems to be particularly marked when Rosiglitazone is combined with insulin, or in patients with a previous or current ischaemic heart disease.
Analysis of Pioglitazone trials did not suggest an increased risk of cardiac ischaemia.
However, comparative data do not provide good evidence of a difference between Rosiglitazone and Pioglitazone for risk of cardiac ischaemia events.

Source: MHRA – Drug Safety Update, 2007

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