4.5 Drugs used in the treatment of obesity

Obesity is associated with many health problems including cardiovascular disease, diabetes mellitus, gallstones and osteoarthritis. Factors that aggravate obesity may include depression, other psychological problems and some drugs.

The main treatment of the obese individual is a suitable diet, carefully explained to the individual, with appropriate support and encouragement; the individual should also be advised to increase physical activity.

Severe obesity should be managed in an appropriate setting by staff that have been trained in the management of obesity; the individual should receive advice on diet and lifestyle modification and be monitored for changes in weight as well as in blood pressure, blood lipids and other associated conditions. Drug therapy must only be offered as part of a package of care if there is demonstrated weight loss prior to treatment.

  • NICE TA494: Naltrexone-bupropion is not recommended for managing overweight and obesity in adults alongside a reduced-calorie diet and increased physical activity (December 2017)

Centrally acting appetite suppressants

Phentermine and diethylpropion are central stimulants; they are not recommended for the treatment of obesity. Phentermine has been associated with a risk of pulmonary hypertension.

Sibutramine, dexfenfluramine, and fenfluramine have been withdrawn from the market because the benefit of treatment does not outweigh the risk of serious adverse effects.

Lipase inhibitors

  • Capsules 120mg (£28.05 = 84 capsules)


  1. NICE CG43: (December 2006) recommends that orlistat should be prescribed under the following conditions:
    • Part of an overall plan for managing obesity in adults who have a body mass index (BMI) of 28kg/m2 or more with associated risk factors, or
    • a BMI of 30kg/m2 or more.
  2. Treatment should be continued beyond three months only if the person has lost at least 5% of their initial body weight since starting drug treatment (although less strict goals may be appropriate for people with type 2 diabetes).
  3. Therapy should only be continued beyond twelve months (usually for weight maintenance) only after discussing potential benefits and limitations with the patient.
  4. Co-prescribing with other drugs for weight reduction is not recommended.

Melanocortin 4 receptor agonist

  • Solution for injection 10mg in 1ml


  1. NICE HST21: Setmelanotide (Imcivree) is recommended, within its marketing authorisation, as an option for treating obesity and controlling hunger caused by pro-opiomelanocortin (POMC) deficiency, including proprotein convertase subtilisin/kexin type 1 or leptin receptor (LEPR) deficiency in people 6 years and over, only if the company provides setmelanotide according to the commercial arrangement (July 2022).


Home > Formulary > Chapters > 4. Central Nervous System > 4.5 Drugs used in the treatment of obesity


  • First line
  • Second line
  • Specialist
  • Hospital