What should I do if I experience severe side effects?

Contact your prescriber, GP, or call NHS 111. For serious symptoms such as severe abdominal pain, allergic reactions, or thoughts of self-harm, seek immediate medical attention or call 999.

Safety & Side Effects

Quick Answer

Contact your prescriber, GP, or call NHS 111. For serious symptoms such as severe abdominal pain, allergic reactions, or thoughts of self-harm, seek immediate medical attention or call 999.

Detailed Answer

If you experience side effects that concern you, the first step is to contact your prescriber or GP for advice. Most side effects of GLP-1 medications are mild and manageable, but some symptoms require urgent attention.

You should seek immediate medical attention (call 999 or go to A&E) if you experience: severe, persistent abdominal pain (possible sign of pancreatitis); severe allergic reaction including swelling of the face, lips, tongue, or throat, difficulty breathing, or widespread rash; signs of severe dehydration from persistent vomiting or diarrhoea (dark urine, dizziness, rapid heartbeat, confusion); thoughts of self-harm or suicide.

You should contact your prescriber urgently or call NHS 111 if you experience: persistent vomiting preventing you from keeping fluids down for more than 24 hours; significant changes in mood, anxiety, or emotional state; yellowing of the skin or eyes (jaundice); unusual fatigue or malaise that persists.

You can also report suspected side effects directly to the MHRA through the Yellow Card scheme at yellowcard.mhra.gov.uk. Reporting helps the MHRA monitor the safety of all medicines and identify emerging concerns.

Remember: never stop taking a prescribed medication without discussing it with your prescriber first, unless you are experiencing a medical emergency.

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Important Medical Information

This website provides general information about weight loss medications for educational purposes only. It is not intended as medical advice, diagnosis, or treatment. Always consult your GP or qualified healthcare professional before starting any weight loss medication. Individual results may vary.

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Sources & References

  1. 1
    Yellow Card Scheme — Report a side effectMHRA (Accessed February 2026)View source
  2. 2
    GLP-1 medicines for weight loss — what you need to knowMHRA (Accessed February 2026)View source