Managing Mounjaro, Saxenda and Wegovy side effects
As with all medicines, Mounjaro, Wegovy and Saxenda may cause some side effects. Mostly, these should be mild and are likely to lessen or even disappear after a few weeks of starting treatment. We’ve prepared a list of the most common side effects for each medicine on our Mounjaro, Saxenda and Wegovy pages.
We understand how tough it can be to live with these discomforts as your body is getting used to the medicine. That’s why we’ve put together our top tips for managing these possible side effects to hopefully help ease any discomfort.
If you have any more questions or are concerned about the side effects you’re experiencing, please contact us through your online patient record.
All Mounjaro and Wegovy side effects should be reported via the Yellow Card Scheme.
For Saxenda, only side effects not already listed in the patient information leaflet need to be reported.
Click below for tips on how to manage some of these side effects.
Nausea and/or heartburn
Nausea and heartburn are common side effects affecting around 1 in 10 users, and are seen with increasing doses of Mounjaro, Wegovy and Saxenda.
To help with heartburn, nausea or vomiting we advise you to:
- drink plenty of clear fluids such as water and herbal teas
- eat small amounts regularly
- drink or sip ginger, peppermint or fennel teas
- reduce sugar intake and high fat foods
- get plenty of fresh air
- distract yourself by listening to music or watching a film
- avoid cooking or eating strong smelling food
An over the counter antacid medicine can also help as your body adjusts to the higher dose. Your Boots or local pharmacist can help you with these.
Constipation
Constipation is a very common side effect affecting more than 1 in 10 people using Mounjaro, Wegovy and Saxenda.
To help with constipation we advise you to:
- drink plenty of clear fluids such as water and herbal teas
- try to eat small fruits such as prunes, figs or grapes
- increase the fibre in your diet
- add some wheat bran, oats or linseed to your diet
- ensure you are having regular walks
You may wish to try a mild laxative to help, which your Boots or local pharmacist can help you with. Visit the NHS website for more information on dealing with constipation.
Headache
Headache is a very common side effect of Wegovy and Saxenda affecting more than 1 in 10 users. This tends to settle within a few days, but may last a few weeks.
Our tips to help with headaches:
- drink plenty of clear fluids
- eat small amounts
- a simple pain medicine, such as paracetamol, taken for a few days can help as your body gets used to Wegovy and Saxenda
- rest in a quiet place with dim lighting
- relaxation strategies such as meditation, focussing on your breathing and on relaxing different muscle groups at a time
- DIY scalp/temple massage
- exercise
- applying hot or cold compresses to your head and/or neck
- sipping on warm herbal teas such as ginger, chamomile and peppermint
- ensure you are getting enough sleep
If your headache symptoms persist, become worse or you remain worried please contact your GP or NHS 111 for further advice.
Vomiting
More than 1 in 10 people who use Mounjaro, Wegovy and Saxenda experience vomiting.
A key to managing this, and most other side effects, is good hydration. Make sure you are drinking plenty of water.
In addition:
- eat small amounts regularly
- drink ginger, peppermint or fennel teas
An over the counter antacid medicine can help as your body adjusts to the higher dose. Your Boots or local pharmacist can help you with these.
Vomiting more than 3 times a day may suggest that Mounjaro, Wegovy and Saxenda are not suited to you. Please keep an eye on your symptoms.
If your urine turns a dark colour, or you feel light-headed, this may be a sign that you are dehydrated and need to drink more fluids. If this is not possible, or you are becoming more unwell, you need to call NHS 111 for further advice.
Diarrhoea
This is a very common side effect experienced by more than 1 in 10 people who use Mounjaro, Wegovy and Saxenda.
The key thing to managing this is to keep hydrated. Make sure you are drinking plenty of clear fluids (such as water or squash).
In addition:
- make sure you rest
- eat small amounts regularly; there isn’t anything in particular that you should avoid
- a simple pain reliever like paracetamol can help if you are in discomfort
- consider oral rehydration salts. Speak with your Boots or local pharmacist about these
If diarrhoea persists over a few days, you are unable to tolerate any fluids, you have bloody diarrhoea or there is bleeding from your bottom, you must call NHS 111 for further advice.
Injection site reactions
Up to 1 in 10 people who use Mounjaro, Wegovy and Saxenda experience injection site reactions. These include redness, bruising, itching, swelling and pain. These tend to settle as your body gets used to the drug. Until then you may wish to try a non-drowsy antihistamine tablet or a local antihistamine cream. Your Boots or local pharmacist can help you with this.
In a few patients redness and itching remains while using Mounjaro, Wegovy and Saxenda.
If your rash is getting worse, spreading, becoming more red or the pain is not tolerable please stop using Mounjaro, Wegovy or Saxenda and seek further help from your GP, NHS 111 or A&E. Please also let us know this happened from your patient account.
Gallstones and inflammation of the gallbladder
Gallstones are common in the general population, and many people don't even know they have them.
Up to 1 in 10 users of Wegovy and Saxenda develop gallstones (up to 1 in 100 for Mounjaro users), and up to 1 in 100 get an inflamed gallbladder. The main reason for this is rapid weight loss of around 1.5kg (over 3 pounds) a week. Inflammation of the gallbladder (cholecystitis) is seen more in those that use Mounjaro, Wegovy or Saxenda.
You can use Mounjaro, Wegovy and Saxenda if you are have gallstones. We’ll consider this and other factors to assess whether weight loss medicine is suitable for you in your consultation.
If you develop abdominal pain, especially on the right side under your ribs you must seek medical attention.
If you develop severe pain/ vomiting/ any blood in your urine or a high temperature, please call NHS 111 for advice, or attend A&E. We encourage you to continue to eat small meals throughout the day, so that weight loss doesn’t occur too quickly. Aim to stay well hydrated.
Changing your dose if you experience side effects
Unpleasant side effects
These usually go away within a few days or weeks. If you’re taking Saxenda, you should stay on your current dose for up to another week before increasing the dose as described in the dosing schedule. If you’re taking Mounjaro or Wegovy, get in touch with us for advice through your patient account. You can also report any side effects you experience with Mounjaro or Wegovy through the Yellow Card Scheme.
Strong side effects
If you’re taking Saxenda, drop down to the previous lower dose for up to another 7 days before increasing again. If you’re taking Mounjaro or Wegovy, get in touch with us for advice through your patient account.
Please note, if your side effect symptoms persist on the lowest dose, then Mounjaro, Saxenda or Wegovy may not be suited to you.
Severe and intolerable side effects
You should immediately stop the medication. If you have very severe abdominal pain contact your GP, NHS 111 or attend A & E as pancreatitis is a rare but serious side effect.
Some people find they cannot tolerate Mounjaro, Saxenda or Wegovy.
Serious side effects
In rare cases, serious side effects may be experienced. You should be aware of these and make sure you stop treatment and seek medical attention.
Pancreatitis
This is an uncommon but serious side effect. Most patients feel very unwell with it.
If you have severe abdominal pain which might reach through to your back, as well as nausea or vomiting call 111 for advice, or attend A & E.
Anaphylaxis
This is a rare severe allergic reaction. If you have difficulty breathing, or there is swelling of your face, tongue or throat, call 999 or attend A & E.
Lumps and cancer concerns while using Saxenda, Wegovy and Mounjaro
There have been some theoretical links discussed about using Saxenda, Wegovy or Mounjaro and thyroid lumps and cancer. These are based on studies in rodents, but have not been seen in primate or human studies.
A thyroid goitre is a swelling in the thyroid gland. About 15% of the UK population have thyroid goitres or nodules, and the lifetime risk of developing a thyroid nodule is around 5 to 10%.
Saxenda, Wegovy and Mounjaro clinical studies showed an increased risk of developing thyroid swellings, like goitres, particularly in patients with pre-existing thyroid disease.
If you have thyroid disease and develop a swelling in your neck or thyroid whilst using Saxenda, Wegovy or Mounjaro, you must tell your doctor.
Thyroid cancer is the 20th most common cancer in the UK, accounting for 1% of all new cancer cases. 8% of thyroid cancers are caused by being overweight or obese. Find out more on the Cancer Research UK website.
Clinical trials carried out on rats and mice showed an increase in thyroid cancer. In particular, this was medullary cancer of the thyroid. This increase was not seen in studies carried out on primates, and importantly has not been seen in human studies on many thousands of patients.
Pancreatic cancer is the 10th most common cancer in the UK. Almost half of all new cases are diagnosed in people aged 75 and over. A person’s risk of developing cancer depends on many factors. To put this into context, 22% of pancreatic cancers are caused by smoking, and 12% by being overweight or obese. Find out more on the Cancer Research UK website.
Saxenda, Wegovy and Mounjaro clinical studies have not shown a link with pancreatic cancer.
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Last reviewed on: 06/02/2024