The British Heart Foundation (BHF) has warned that people using weight loss jabs should contact NHS 111 if they experience sudden severe abdominal pain, a symptom of acute pancreatitis. This serious side effect may affect up to one in 100 patients, according to patient data.
Weight loss medications, known as GLP-1 inhibitors, work by mimicking a hormone that regulates blood sugar and suppresses appetite. While effective for diabetes management and weight loss, the BHF highlights that acute pancreatitis—a sudden inflammation of the pancreas—is a potential risk. Symptoms include intense pain in the middle of the abdomen, fever, nausea, and vomiting.
Common side effects, affecting one in 10 users, include digestive issues such as nausea, diarrhoea, constipation, and abdominal discomfort. The BHF advises speaking to a doctor if these occur, as dose adjustments may be needed. Other reported effects include tiredness, dizziness, hair loss, low blood sugar, and rapid heart rate.
The Medicines and Healthcare products Regulatory Agency (MHRA) has also flagged rare cases of vision loss linked to semaglutide (Wegovy), requiring urgent specialist referral. Additionally, Mounjaro may reduce the effectiveness of contraceptive pills; the MHRA recommends using non-oral contraception instead. Weight loss injections should not be used during pregnancy, when trying to conceive, or while breastfeeding.
Poor nutrition is another concern due to reduced food intake. The BHF emphasises maintaining a balanced diet with adequate protein, calcium, and vitamin D, alongside regular exercise to protect muscle and bone health. Anyone experiencing adverse effects should consult their GP promptly.
