Mounjaro (tirzepatide)

What Mounjaro is licensed to treat

Tirzepatide acts on two gut hormone receptors, GIP and GLP-1. Together these actions slow stomach emptying, reduce appetite and help the body release insulin after meals. The current Summary of Product Characteristics (SmPC) on the EMC lists two licensed uses.

The first is type 2 diabetes. Mounjaro can be used alone when metformin is unsuitable, or added to other diabetes medicines. The current SmPC covers adults, adolescents and children aged 10 and over for this indication.

The second is weight management, including weight loss and weight maintenance. This applies to adults with a BMI of 30 or above, or a BMI from 27 up to 30 with at least one weight-related condition such as high blood pressure, raised cholesterol, sleep apnoea, heart disease, prediabetes or type 2 diabetes. The MHRA added this indication on 8 November 2023.

NHS access for weight management in England

NICE recommended tirzepatide for overweight and obesity in technology appraisal TA1026. NHS England then set out interim commissioning guidance with a phased rollout over three years. Specialist weight management services started prescribing from 24 March 2025. GP practices and other primary care services began on 23 June 2025.

The first primary care group (2025 to 2026) covers people with a BMI of 40 or more and at least four of five named conditions: high blood pressure, abnormal blood fats, obstructive sleep apnoea, cardiovascular disease and type 2 diabetes. Later years widen the BMI band. Every NHS patient on tirzepatide for weight management must also receive wraparound care, with diet and nutrition advice and support for behaviour change.

Wales, Scotland and Northern Ireland make their own commissioning decisions, so check the local health board or trust position before you tell a patient what the NHS offers where they live.

Safety points from the MHRA and NHS

The MHRA page on GLP-1 medicines and the NHS medicine guide set out the main points to cover in a consultation.

• Nausea, vomiting, diarrhoea and constipation are common. Severe vomiting or diarrhoea can cause dehydration serious enough to need hospital care.
• Acute pancreatitis is rare but can be serious. Severe stomach pain spreading to the back needs urgent medical help.
• Gallstones and an inflamed gallbladder are listed by the NHS as rare serious side effects.
• Low blood sugar is more likely when tirzepatide is used with insulin or a sulfonylurea.
• Tirzepatide can make the oral contraceptive pill less effective. The MHRA advises adding a barrier method for four weeks after starting and for four weeks after each dose increase, or switching to a non-oral method.
• Tirzepatide should not be used in pregnancy or while breastfeeding. The MHRA advises stopping at least one month before trying to conceive.
• The slower stomach emptying raises the risk of aspiration under general anaesthesia or deep sedation. Patients should tell the surgical team and anaesthetist.

The GLP-1 safety guide sets these points against the other medicines in the class.

Demand and consultation time at work

Since the weight-management licence, pharmacy teams, GP practices and online services have handled a large rise in requests. Each request still needs a proper assessment: a checked weight and height, a history which picks up pancreatitis, gallbladder disease, pregnancy plans and current medicines, and time for questions.

Say a pharmacist is booked for ten-minute slots and a patient raises contraception, an operation next month and a past eating disorder. Ten minutes is not enough for safe advice. Record what you covered, book a follow-up, and tell your manager which parts of the assessment the slot length squeezes out. The workload guide covers how to raise staffing and time limits in writing.

Pressure to prescribe or supply

Staff describe pressure from patients who want treatment the same day, from targets linked to new sign-ups, and from managers who see refusals as lost business. Your professional duty sits with the patient in front of you. If a request falls outside the licence or the assessment raises a concern, you are entitled to decline and document your reasons.

The guide to pressure to prescribe sets out what to say and how to record the decision. The commercial pressure guide covers sales targets and incentive schemes. UK law bans advertising prescription-only medicines to the public, and the MHRA warned businesses about weight-loss advertising again in June 2026.

Safe supply and fake pens

The MHRA warns about counterfeit pens which closely resemble genuine products, and about powder vials sold for mixing, which are not authorised. Supply only through legitimate wholesale channels. If a patient shows you a pen bought online or through social media, treat the product as suspect, advise against using the pen, and report the case.

Supply problems also hit diabetes patients when demand for weight loss rises. The shortages and demand guide covers how teams can share a fair response when stock runs short.

Reporting side effects and concerns

Report suspected side effects, and suspected fake or faulty products, to the MHRA Yellow Card scheme (opens another website). Healthcare staff and patients can both report, online or through the Yellow Card app. Report even when you are unsure the medicine caused the problem.

Concerns about how a service is run need a separate channel. The guide to raising patient-safety concerns and the speaking-up guide explain how to escalate inside your organisation and to a regulator.

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