Mounjaro weight loss jab side effects as GPs issue prescriptions from Monday

A mass rollout of weight loss jabs on the NHS in England begins today as GPs are now allowed to prescribe the drugs for the first time.

Around 220,000 people with the “greatest need” are expected to receive Mounjaro, also known as tirzepatide, through the NHS over the next three years to manage obesity. Mounjaro is a weight loss drug that makes you feel fuller for longer, and therefore less hungry, and comes in the form of an injection that patients can administer themselves once a week. The drug works by lowering blood sugar levels and slowing down how quickly food is digested.

In the first year of its rollout, the drug will be offered through the NHS only to patients with a body mass index (BMI) score of 40 and at least four other health problems linked to obesity. Previously, the drug was only accessible to patients through a special weight loss service.

The NHS says those who are using the jab will need to eat a balanced, reduced-calorie diet and do regular exercise while taking it. But while the drug can help to aid weight loss, like all medications, it can also cause some side effects. The NHS says these can include:

• nausea
• vomiting
• indigestion
• constipation
• diarrhoea

There can also be some more serious – although less common side effects – such as low blood sugar, gallstones, kidney failure, vision changes and pancreatitis.

If you do experience any side effects and are concerned you should speak to your GP and report these symptoms through the Yellow Card Scheme, which is run by the Medicines and Healthcare products Regulatory Agency (MHRA).

The NHS says: “Like all medications, Tirzepatide can have side effects, and healthcare professionals should discuss these with you.

“The medication comes with a patient information leaflet listing common side effects, including feeling sick, indigestion, constipation, and diarrhoea. There can be some more serious side effects, such as low blood sugar, gallstones and inflammation of the pancreas (pancreatitis).

“Tirzepatide is a new medication, and any side effects should be reported through the Yellow Card Scheme, the Government’s system for tracking medicine-related side effects.”

Additionally, the drug is not recommended for people who are pregnant, planning to get pregnant or who are breastfeeding. Anyone taking the contraceptive pill and using Mounjaro is advised to use an additional non-oral method of contraception for the first four weeks of treatment, and for four weeks after each dose increase, as the pill may not be properly absorbed by the body.