22 January 2010
The MHRA has announced that the licence for sibutramine has been suspended throughout Europe. This follows a review which considered the increased risk of non-fatal heart attacks and strokes seen in a recent study.
Prescribers should not issue any new prescriptions for sibutramine and should review the treatment of those who are currently taking this medicine. Pharmacists should not dispense any prescriptions for sibutramine and should advise patients to make an appointment to see their doctor at the next convenient time. Patients who are currently being treated with sibutramine should be advised to schedule an appointment at the next convenient time with their doctor to discuss alternative measures to lose weight, including use of diet and exercise regimens. Patients may stop treatment before their appointment if they wish.
Why has sibutramine’s licence been suspended?
According to a ‘Dear Healthcare Professional’ letter from the MHRA, this follows a review based on new safety information from a large clinical trial, the Sibutramine Cardiovascular OUTcomes (SCOUT) study. The review concluded that the cardiovascular risks of sibutramine outweigh its benefits.
The SCOUT study was a randomised, double-blind, placebo controlled study in approximately 10,000 obese and overweight patients with cardiovascular disease and/or type 2 diabetes treated over a six year period. The results of the study showed that patients treated with sibutramine experienced a 16% increased risk of cardiovascular events such as myocardial infarction and stroke compared with placebo-treated patients (hazard ratio [HR] 1.161, 95% confidence interval [CI] 1.029 to 1.311, P=0.016).
The Committee for Medicinal Products for Human Use (CHMP) of the EMEA, which conducted the review, noted that the mean weight loss achieved with sibutramine in all clinical trials is modest, with sibutramine decreasing body weight by approximately 2kg to 4kg more than placebo.
Although most of the patients enrolled within SCOUT are contraindicated from being treated with sibutramine under normal conditions of use, the CHMP considered the cardiovascular risk to be relevant to normal clinical use because it is not always possible to identify underlying cardiovascular disease in patients who are obese or overweight. Further restrictions on the use of sibutramine would be therefore be unlikely to reduce the risk to an acceptable level.
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