Side Effect – Diarrhoea

Diarrhoea: Symptoms & Treatment 

Diarrhoea is a common side effect of GLP-1 medications (such as Wegovy and Mounjaro. This happens because these medicines slow down how quickly food moves through your digestive system. Most people find that symptoms improve as their body adjusts over time. Please do not stop your GLP-1 medication without speaking to your provider.

Symptoms of diarrhoea may include:

• Frequent, loose, or watery stools
• Abdominal cramping or pain
• An urgent need to have a bowel movement
• Bloating or discomfort
• Nausea
• Dehydration (which may cause dizziness, dry mouth, or fatigue)

The risk of developing these symptoms is generally highest during the initial weeks of treatment and following dose increases, with symptoms usually improving as your body adjusts to the medication.

If you experience diarrhoea, here are some practical tips you can try:

• Dietary recommendation:

• Drink plenty of clear fluids to prevent dehydration and stay well hydrated
• Eat as normally as possible. Try to include fruit juices and soups, which will provide sugar and salt, and also foods that are high in carbohydrate, like breads, pasta, potatoes or rice
• Avoid triggers such as spicy foods, caffeine, alcohol and fatty or fried foods
• Eat smaller, frequent meals rather than large portions
• Consume soluble fibre sources like oats and psyllium husk to add bulk to stools

• Supplements and Medical Interventions:

• Replenish electrolyte lost, with balanced supplements like ORS or Dioralyte sachets to prevent dehydration
• Over the counter medications like loperamide (Imodium) can be used and use should be limited to less than 3 days
• Bismuth subsalicylate (Pepto Bismol) used for mild to moderate gastrointestinal symptoms
• Probiotics can be tried specifically formulated for diarrhoea.

• Lifestyle Adjustments

• Maintain a food diary to identify specific food triggers
• Identify stress triggers that may worsen symptoms
• Ensure easy access to toilets when outside the home
• Consider timing activities around predictable bowel patterns

Follow the prescribed dosing schedule, as increasing doses too quickly may worsen side effects. If your symptoms become difficult to manage, a temporary pause in dose escalation or a reduction in dose may be appropriate. Please discuss any changes to your treatment with your provider before adjusting your medication.

For most patients, diarrhoea is a temporary side effect that improves as the body adapts to GLP-1 medication. Many people find that symptoms improve or resolve with appropriate dietary changes, identifying food triggers, and supportive self care measures.

GLP-1 related diarrhoea often develops after starting treatment or following a dose increase. It may follow a predictable pattern linked to these changes. Keeping a food diary can help identify contributing factors and support symptom management.

Diarrhoea does not affect the absorption or effectiveness of injected GLP-1 medications. However, if diarrhoea persists, it may impact your appetite, hydration, and overall wellbeing. If your symptoms continue or worsen, please seek advice from your healthcare provider.

When to Seek Urgent Medical Advice

Please contact your GP or your local Out of Hours service as soon as possible if you experience:

• Diarrhoea which lasts more than 2-3 days with no improvement
• Frequent or ongoing diarrhoea that is not improving with self care
• Signs of dehydration (increased thirst, dark urine, light headedness, dizziness)
• Blood or mucus in stools
• Severe abdominal pain
• Fever

Call 999 or go to your Nearest A&E Immediately if you experience:

• Severe signs of dehydration (confusion, collapse, or inability to keep fluids down)
• Large amounts of blood in your stool or have heavy rectal bleeding
• Black, tarry stools
• Unexplained weight loss
• Severe, constant abdominal pain or a rigid, tender abdomen
• Signs of severe illness such as high fever with worsening symptoms, confusion, or drowsiness
• Unable to keep any fluids down alongside ongoing vomiting and diarrhoea

Important Safety Advice

It is important to use GLP-1 medications safely and in line with clinical guidance. Side effects can often be managed effectively when identified early and addressed appropriately.

Maintaining open communication with your provider is key to ensuring safe and effective treatment.

Remember:

• Do not ignore persistent or worsening symptoms
• Do not increase your dose without clinical advice
• If you have had a break in treatment, restarting at a lower dose may reduce side effects
• Ensure your GP is informed of any new or unusual symptoms

Additional support

If you are experiencing side effects or have any questions about your treatment, our clinical team is here to help.

If your symptoms are severe, worsening, or you feel they require urgent medical attention, please seek immediate advice from your GP, NHS 111, or attend your nearest A&E department if appropriate.

For all other queries:

• Book a free video consultation with one of our trained clinicians through our website. Appointments are available throughout the week, including daytime and evening sessions.
• Send us your question online using our form: https://forms.medicinemarketplace.com/251345635207050 A member of our clinical team will respond by email.
• Speak to us by phone by calling 0330 175 5747, and selecting option 3.

We are here to answer your questions and provide support throughout your treatment journey.

Written by: Uzma Dala MPharm (2238839)

Approved by: Shameela Adam MPharm (2070113)