Slimming pills don't work. Obese people regain any weight they lose as soon as they come off the pills, the US national task force on the Prevention and Treatment of Obesity has concluded.
As such, they shouldn't be recommended for routine use, but should be reserved only for patients who have been carefully selected, the task force recommends.
The other problem is the potential risks linked to the drugs, especially if they are taken for over a year. There is virtually no data that has monitored the drugs over a longer period, but the task force is aware of the risks of pulmonary hypertension (high blood pressure in the lungs), which has been documented with two of the most popular slimming drugs, fenfluramine and dexfenfluramine (N E J Med, 1996; 335: 609-16).
When the task force studied the clinical trials that have investigated these drugs, they found that most people regained much of their weight within two months after coming off the treatment. They were no better off than those who had been given a placebo, or sugar pill (The Lancet, 1996; 348: 1724).