Cardiac fears over obesity drug
By Mark Pownall
Drug regulators have warned GPs about a potential safety risk with the obesity treatment sibutramine after a study that found an excess of serious cardiovascular events in high-risk patients on the treatment.
Both the European Medicines Agency and the US Food and Drug Administration have announced reviews into sibutramine, a centrally acting serotonin and noradrenaline reuptake inhibitor that suppresses appetite.
The UK drugs regulator, the Medicines and Healthcare products Regulatory Agency, said: ‘Patients with existing cardiovascular diseases should not be prescribed sibutramine and blood pressure and heart rate should be carefully monitored during treatment.'
The MHRA called on GPs to ensure they followed safety advice in the drug's prescribing information.
Preliminary results from the Sibutramine Cardiovascular Morbidity/Mortality Outcomes (SCOUT) study given to the FDA showed that 11.4% of patients taking sibutramine had a heart attack, stroke, resuscitated cardiac arrest or death compared with 10% of those taking placebo.
Patients taking part in SCOUT were aged over 55, overweight or obese, and had a history of heart disease or type 2 diabetes with an additional cardiovascular risk factor so they were at high risk of heart disease. The study was designed to see whether effective weight reduction in overweight and obese patients at high cardiovascular risk could reduce the incidence of cardiovascular outcomes.
The FDA said the findings emphasised the importance of avoiding sibutramine in patients with heart disease, heart failure, arrhythmias and stroke, all contraindicated in prescribing advice (see box below).
A statement from Abbott, which markets sibutramine in the UK, said: ‘Abbott is reviewing and evaluating the SCOUT study, and discussing the data with regulatory authorities. At the current time we do not think the data indicates a change in the safety profile of sibutramine when used according to the approved prescribing information.'
The MHRA said it had been informed in late October of preliminary data on cardiac deaths and cardiovascular problems that raised concerns regarding the long-term safety, efficacy and benefit of sibutramine.
‘Doctors are advised to carefully note the safety advice contained in the product information' it said.
Dr Ian Campbell, a GP in Nottingham and medical director of the charity Weight Concern, said: 'The results from SCOUT are disappointing - as it shows sibutramine does increase the risk of CV events in these patients - but not a surprise.'
'When balanced against the increased risk of CV events through being obese, prescribing sibutramine can be justified as long as their blood pressure and pulse are closely checked. As a weight loss drug, sibutramine does still have a role to play but lifestyle changes remain the fundamental approach to weight loss.'Current advice on sibutramine use
Contra-indicated if there is a history of
• Coronary artery disease
• Congestive heart failure
• Peripheral arterial disease
• Cerebrovascular disease
• Uncontrolled hypertension
Monitor blood pressure and pulse rate every 2 weeks for first 3 months then monthly for 3 months then at least every 3 months
Source: www.bnf.orgGPs are being warned to follow sibutramine prescribing advice carefully GPs are being warned to follow sibutramine prescribing advice carefully