Private prescribing for obesity drugs are on the rise - What do we need to be aware of?

We have entered a new era of effective medical management of obesity. The press and medical literature are full of stories about the current medications that are available. Semaglutide, which is available as Wegovy for obesity management and Tirzepatide, available as Mounjaro. The latter is only available privately for the management of obesity currently, but NICE has now released its consultation document (https://www.nice.org.uk/guidance/indevelopment/gid-ta11156/consultation/html-content-8) which suggests that Tirzepatide may be made available for prescription by GPs for the treatment of obesity. This BMJ Summary explains it further.

We are currently in a rather unfamiliar situation in the UK where we are used to the NHS providing medications. Patients who have money to spend, are able to access these very effective medications, whilst those who may desperately need them but are not able to fund them, are not accessing them at all. The government’s widely touted community provision of Wegovy for patients with obesity is yet to be implemented and very few patients are getting it via Tier 3 services, if they can even access those services.

Meanwhile, the private prescribing of these medications is booming – and fast. It isn’t possible to get data on how much is being prescribed and to whom, but I doubt I am alone in having many people I know personally, using them. 

This begs the question, what do I need to know if my patient is accessing this medicine privately? Do I need to do anything and what side effects or concerns might I need to have?

Some private prescribers will ask for GP details, others don’t. So you may not know until you see someone who seems to have lost a lot of weight, or they consult you about a problem. Some private prescribers make efforts to ensure a patient doesn’t have an eating disorder and that they do have obesity, others don’t. Very few ask for a face to face appointment or video appointment, so there will be patients who do not have overweight or obesity accessing these medications. If this is occurring, you almost certainly have an ethical duty, with patient consent, to let the private provider know. 

Serious side effects are luckily rare, but if someone develops signs of pancreatitis, we should be asking if they are taking these medications.

Common side effects are gastrointestinal, including delayed gastric emptying, one of the methods that these medications improve satiety. There has been anecdotal concern that this may affect the efficacy of oral contraceptives, but there is no published data on this yet. It may be however that you should advise women to be on a non-oral form of contraception until more is known and they should be on contraception whilst taking the medication and for two months after stopping. 

If patients are going to have surgery, they should advise the pre-operative assessment nurse that they are taking these medications. This study from the US explains that patients may need to fast for longer and may need gastric ultrasound pre-op.

Nutritional status and the development of sarcopenia have been two areas of developing interest. This recent study in JAMA (2024) seems to be reassuring with regards to sarcopenia, as the increased movement from weight loss makes activity more likely. It does however caution regarding its use in the elderly, who are more at risk of frailty and those who lose over 25% of their bodyweight. It is vital to encourage patients who can, to do weight bearing exercise to ensure they maintain their muscle mass whilst on these medications. 

There is yet to be much official research into the nutritional status of people who have used the drug for longer periods, does the decreased food intake make vitamin and mineral deficiencies more likely for example? Until more evidence becomes available, should we perhaps be advising people to take a good quality vitamin and mineral supplement, as we do for those who have had bariatric surgery and monitor iron, B12 and folate? There is no official guidance on this yet, but it may be a sensible precaution.

This area of medicine is moving fast and whilst the private prescribing market is unregulated and expanding rapidly, we need to remain professionally aware of the medications and ask patients directly if they are accessing them, in a non-judgemental fashion. Obesity stigma means many won’t volunteer the information, but we need to know so that we can then advise our patients of the above issues to ensure they come to no harm.