Related guidance:

Obesity: identification, assessment and management Clinical guideline (CG189 November 2014, updated September 2022)

Obesity prevention Clinical guideline (CG43 December 2006, updated March 2015)

Therapeutic AreaFormulary ChoicesCost for 28
(unless otherwise stated)
Rationale for decision / comments
Lipase inhibitorsOrlistat120mg capsule: £25.58 (84)


Do not prescribe as Alli® as not cost effective.
Only to be prescribed in line with NICE guidance:

• BMI > 30kg/m2 or > 28kg/m2 where other risk factors e.g. type 2 DM, hypertension or hypercholesterolaemia

• for patients who have lost ≥ 2.5kg by dietary control and increased physical activity during previous month

• only for individuals between 18 and 75 years

• arrangements should exist for primary care staff (mostly practice nurses) supported by community dieticians to offer advice, support and counselling on diet, physical activity and behavioural strategies

• treatment should continue beyond 3 months only if weight loss of >5% from start of treatment

• discontinue treatment with orlistat after 12 weeks if the person has not lost at least 5% of their body weight (as measured at the start of drug treatment). Rates of weight loss may be slower in people with type 2 diabetes, so less strict goals (for example a loss of more than 3% of their body weight in 12 weeks) may be appropriate.
These goals should be agreed with the person and reviewed regularly.

• for people who have lost the recommended amount of weight, there is no restriction on how long orlistat may be prescribed. The decision to continue treatment should be made on an individual basis, taking into account the benefits, risks, and cost of treatment. This should be reviewed at regular intervals.
Antidepressants, serotonin and noradrenaline re-uptake inhibitorsAdvise patients that naltrexone/bupropion has been associated with adverse reactions such as dizziness or somnolence, which can affect ability to drive, operate machinery, or perform dangerous tasks. Advise patients not to drive if they suspect their ability may be impaired. See MHRA (August 2019) for Naltrexone/bupropion: risk of adverse reactions that could affect ability to drive.
NHS Somerset classify Naltrexone / Bupropion as not recommended for managing overweight and obesity as per Traffic light guidance.