The anorectic agents fenfluramine, dexfenfluramine, phentermine and amfepramone (diethylpropion) have been withdrawn in the European Community. Following a review of the risks and benefits of these drugs by the European Committee for Proprietary Medicinal Products (CPMP), the European Commission decided that the drugs' licences should be withdrawn. Licences were withdrawn in the UK on April 9. Safety concerns previously reported with these drugs have related to primary pulmonary hypertension and heart valve disorders.
This action follows the withdrawal of fenfluramine (Ponderax) and dexfenfluramine (Adifax) in the UK in 1997 after reports of adverse effects on heart valves. However, phentermine (Duromine, Ionamin) has remained on the market. Amfepramone (Tenuate Dospan) has not been actively marketed in recent years.
The withdrawal of the anorectic agents is to be reported in April's Current Problems in Pharmacovigilance from the Committee on Safety of Medicines (CSM) and Medicines Control Agency (MCA). However, an extract concerning the subject has been distributed to pharmacists and general practitioners in advance, along with an information sheet for patients. The CSM and MCA emphasise that there are no new safety problems but that the risks are seen to outweigh the benefits.
They recommend that no further patients should be initiated on phentermine or amfepramone. In patients currently taking them, the drugs should be withdrawn by dosage reduction over one to two weeks to reduce the risk of withdrawal symptoms.
Withdrawal symptoms are not expected in patients who have been taking the drugs for less than three months. However, the CSM and MCA say that abrupt discontinuation, particularly after long-term use, could produce withdrawal symptoms such as depression, irritability, dizziness and sleep disturbance. Such symptoms are, they say, usually most severe by the fourth day after stopping treatment but may occur later.
Stocks The manufacturers of Duromine (3M Health Care) and Ionamin (Cambridge Healthcare Supplies) say that pharmacists should return stocks of these drugs to their wholesalers.