Work out what has changed
Note when the loose stools started, how often you go and whether they began after a dose increase, a new medicine, travel or illness in someone close to you. Blood, fever, significant pain and recent antibiotics are the details a clinician most wants to hear.
A short symptom diary stops everyone assuming semaglutide caused every episode. Food poisoning, a viral infection, inflammatory bowel disease or another condition may need different treatment. If diarrhoea returns after each injection, get it assessed. Do not put up with the pattern.
Replace lost fluid in small, regular amounts
Drink regularly. If you also feel sick, take small amounts often. A pharmacist may suggest an oral rehydration product when you have lost fluid and salts. Make it up exactly as the pack says. A stronger mix does not rehydrate you any better.
Get individual advice if you have kidney disease, heart failure or a fluid restriction. Sugary drinks, large amounts of fruit juice and alcohol tend to make things harder to manage. Keep eating as you can tolerate. An ordinary bout of diarrhoea is no reason for a long fast.
Take care with anti-diarrhoeal medicines
An anti-diarrhoeal medicine helps some adults for a short spell, but suits only some causes. Ask a pharmacist first if you have fever, blood in your stool, severe pain, recent antibiotics or a long-term bowel condition. Do not keep damping down symptoms while you get worse.
Check laxatives, magnesium-containing products and other medicines that may add to the problem. Do not stop prescribed medicines on your own. If you have diabetes, illness and eating less may mean you need the sick-day plan agreed with your diabetes team.
When to get help
Contact NHS 111 or an urgent service if you cannot keep fluids down, still show signs of dehydration after rehydrating, have bloody diarrhoea or feel significantly unwell. Sudden severe tummy pain, confusion, collapse or difficulty breathing may need emergency care.
Persistent diarrhoea needs review too. NHS guidance says to get help when diarrhoea lasts more than seven days. Frailty, kidney disease or other risk factors are reasons to be seen sooner. If your symptoms are severe, do not wait for the seven days to pass.
Contraception and your next dose
Severe diarrhoea can stop the contraceptive pill being absorbed properly. Follow the instructions for your own pill. Ask a pharmacist or sexual health service whether you need extra protection or emergency contraception. This applies whether or not semaglutide interacts with the pill directly.
Contact your Wegovy prescriber before you step up the dose if diarrhoea is ongoing or has cut what you eat and drink. Tell them your last dose and your current symptoms. If an infection is possible, wash your hands well and follow local infection-control advice. People around you may be at risk too, so do not assume a side effect.
Sources
Your own medicine leaflet and prescriber come first. A source from another country does not mean the same rule applies in the UK.
- Wegovy FlexTouch UK prescribing information medicines.org.uk
- Wegovy FlexTouch patient leaflet medicines.org.uk
- NHS: diarrhoea and vomiting nhs.uk
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