Despite the availability of evaluated and approved obesity drugs—and even though some patients will have failed to lose weight after non-drug treatment—doctors have been reluctant to prescribe drugs. The reasons for this may include memories of the adverse events with amphetamine, and amphetamine-like drugs, and the serious complications from combining phentermine and fenfluramine. Current drugs recommended for treating obesity have all been evaluated and approved by regulatory standards that apply to all drug treatments. The use of obesity drugs should follow the principles of any other therapeutic area—that is, they may be prescribed after assessment of the potential benefits and risks (both clinical and economic), with appropriately informed patients, and with medical monitoring of the results of treatment.

Obese patients are at increased risk from cardiovascular disease: it is imperative that risk factors are treated early and optimally. Effective treatment to prevent the underlying cause (body fat accumulation) would make better clinical and economic sense and is now accepted as a reasonable target for drug development

Many people, including doctors, still believe that a short course of drug treatment might “cure” obesity or that efficacy is measured only by ever-continuing weight loss. These misconceptions are at odds with biology: people who become obese have a lifelong tendency both to defend their excess weight and to continue to gain extra body fat. Effective management, including drugs when needed, must be life long and focused on weight loss maintenance in a similar fashion to the effective treatment for hypertension or diabetes. Drug efficacy can be considered in terms of the impact on measures such as body mass index or fat distribution, risk factors, disease improvement, or reduction in clinical end points. Starting drug treatment should always be regarded as a therapeutic trial and stopped if weight loss is not apparent after one …