Mounjaro Side Effects and How To Manage Them
In the UK, it is estimated that at least 1 in 4 adults are currently living with obesity or excess weight. Obesity is a complex chronic condition that can progressively worsen, leading to severe health complications such as type 2 diabetes, heart disease, high blood pressure, and stroke.
For many, weight loss is a difficult journey that may require prescribed weight loss treatments. One such treatment is Mounjaro (tirzepatide), a prescription medication used to treat those with obesity and type 2 diabetes.
As with all medications, Mounjaro can cause side effects such as diarrhoea, appetite loss, nausea, and headaches. In this article, we discuss reported side effects of Mounjaro, how to manage them, and how to report side effects not listed.
What are the side effects of Mounjaro?
Mounjaro, like any medication, can cause side effects. These may not affect everyone. Some side effects of Mounjaro are more common than others and may only be temporary, lasting a few days or weeks. Some side effects may last longer than others and may cause more severe symptoms.
Common side effects of Mounjaro
Very common side effects of Mounjaro may affect more than 1 in 10 people.
Very common side effects of Mounjaro Include:
- Hypoglycemia (low blood sugar), in patients with type 2 diabetes taking medications that contain insulin
- and/or sulphonylurea
- Constipation
- Vomiting
- Nausea
- Diarrhoea
Constipation and vomiting are very common side effects in weight management patients, but only common side effects in type 2 diabetes patients.
Common side effects of Mounjaro include:
- Allergic reaction (e.g., eczema, rash, itching)
- Hypoglycemia (low blood sugar)
- Nausea
- Constipation
- Diarrhoea
- Vomiting
- Decreased appetite
- Stomach pain
- Bloating
- Burping
- Indigestion
- Dizziness
- Flatulence (gas)
- Heartburn or acid reflux
- Fatigue
- Increased levels of pancreatic enzymes
- Fast pulse (common side effect when used for type 2 diabetes patients)
These UK Mounjaro side effects are typically not severe and normally occur when first starting Mounjaro but decrease over time. When Mounjaro is used for weight management, vomiting and constipation are very common side effects.
Uncommon common side effects of Mounjaro
Less common or uncommon side effects of Mounjaro may affect up to 1 in 100 people.
Uncommon side effects of Mounjaro:
- Gallstones
- Increased calcitonin levels in the blood
- Weight loss in type 2 diabetes patients
- Hypoglycemia (when used for patients with type 2 diabetes)
- Fast pulse (in weight loss management patients)
- Cholecystitis (infection of the gallbladder)
- Injection site pain
Rare and severe side effects of Mounjaro
Uncommon serious side effects of Mounjaro may affect up to 1 in 100 people:
- Acute pancreatitis (inflamed pancreas), which causes severe and persistent pain in the back or stomach
If you experience acute pancreatitis, seek a healthcare professional immediately.
Rare serious side effects of Mounjaro may affect up to 1 in 1,000 people:
- Severe allergic reaction (e.g., angioedema, anaphylactic reaction). If you experience allergic reaction symptoms such as struggling to breathe, rapid swelling of the lips, throat or tongue with difficulty swallowing, and a fast heartbeat, seek emergency medical attention by going to A&E or calling 999.
Mounjaro side effects for non-diabetics
As of 2023, Mounjaro can be prescribed as a treatment for obesity (BMI of 30kg/m2 or more) and for adults with excess weight (a BMI between 27-30kg/m2) who have weight-related health conditions.
Mounjaro side effects for non-diabetic weight loss patients may include:
- Injection site reactions
- Vomiting
- Nausea
- Abdominal pain
- Diarrhoea
- Constipation
- Indigestion
- Loss of appetite
Mounjaro side effects: cancer
Mounjaro (tirzepatide) has a precaution and warning for the risk of thyroid C-cell cancer.
During a two year animal study, the active ingredient tirzepatide caused an increase in the occurrence of thyroid C-cell tumours (carcinomas and adenomas). However, animal studies do not always predict how medications affect humans.
It is not currently known if tirzepatide increases the risk of certain types of thyroid cancer in humans. Symptoms of thyroid cancer include:
- Unusual growth or lump in your neck
- Difficulty swallowing
- Shortness of breath
- Hoarseness
Your pharmacist or health care provider will not prescribe Mounjaro for you if you have a family or personal history of medullary thyroid cancer (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2).
Reporting side effects
Side effects of Mounjaro not listed in the PIL can be reported directly via the Yellow Card Scheme, a government system for recording medicine side effects. This helps provide more information on the safety of Mounjaro and its side effects in the UK.
How long after a Mounjaro injection do side effects start?
When side effects start after injecting Mounjaro depends on the person. Side effects may begin after the first injection of Mounjaro or after every dose increase. In most cases, you are more likely to start experiencing side effects in the first few days after beginning Mounjaro.
The severity of side effects typically depends on factors such as the dose strength and overall health status.
How long do Mounjaro side effects last?
How long Mounjaro's side effects last depends on the person and the severity of the side effects. Some common and mild side effects, such as nausea and diarrhoea, may last only a few days or weeks as the body gets used to the medication.
If side effects are serious, such as severe digestive problems and pancreatitis, they may last longer and require long-term treatment.
Talk to your pharmacist or healthcare provider about the possible side effects of Mounjaro and which ones are more likely to affect you. If you experience unpleasant side effects when taking Mounjaro that are not worth the benefits, talk to your pharmacist or healthcare provider about alternative treatment options, such as Saxenda.
Managing side effects of Mounjaro
Below are some tips for managing common side effects of Mounjaro.
Nausea and vomiting
Nausea and vomiting are two of the most common side effects of Mounjaro. These symptoms should pass as you get used to the medication. To help manage the symptoms of nausea and vomiting, you can try:
- Eating smaller and more frequent meals
- Drinking peppermint or ginger tea
- Eating foods that contain ginger
- Reducing rich meals (lots of spices, oily foods, or calorie-rich)
Your pharmacist can help you with treatments to help alleviate nausea and vomiting symptoms if they continue to persist.
Flatulence, burping, and gas
Tirzepatide slows gastric emptying, which may cause gas produced in the intestines to stay longer than normal.
To reduce the build-up of gas in the intestines, try eating smaller meals that do not contain lots of spices or are strongly flavoured.
Dizziness
Dizziness and lightheadedness may be experienced early in Mounjaro treatment while your body is still getting used to the medication. These symptoms may become worse if you are dehydrated, so drinking water can help. If you feel dizzy or lightheaded, you can also try lying down until the sensation passes — be sure to get up slowly.
Headaches
Headaches are most commonly caused by dehydration and may pass quickly once fluids are consumed. If headaches become severe or continue to persist, talk to your pharmacist or health care provider.
Try to maintain good fluid intake. You can also take paracetamol to ease symptoms.
Abdominal pain
There can be many reasons for getting abdominal pain, such as a change in diet or while you adjust to Mounjaro. Abdominal pain typically passes quickly without any further block.
To help avoid stomach pain, try to eat smaller meals that are bland. You can also talk to your pharmacist about over-the-counter treatments.
However, if abdominal pain or constipation becomes severe or does not go away, this may be a sign of something more serious. Talk to your doctor or call 999 immediately.
How to reduce the risk of adverse reactions
Many common side effects of Mounjaro should be resolved in a few days or weeks. To reduce the risk of side effects, follow the dosage and usage instructions exactly as prescribed. The increase in lower dosages to the maintenance dose is designed to allow the body to get used to the medication gradually.
When to seek medical advice
While Mounjaro does have reported side effects, the benefits of the medication are determined to outweigh the side effects. In most cases, the side effects of Mounjaro are mild and go away in a couple of days or weeks.
If the side effects persist and start impacting your quality of life, seek medical advice, as there may be more suitable alternative treatments.
If you experience severe or rare side effects of Mounjaro, seek emergency medical attention by either calling 999 or going straight to A&E.
When in doubt, ask your pharmacist or healthcare provider; they can help answer some questions about Mounjaro's side effects. This also includes any UK Mounjaro side effects not mentioned in the Patient Information Leaflet (PIL) in the box of your Mounjaro KwikPen.
These resources may also help you understand more about Mounjaro and its side effects:
- Mounjaro Patient Information Leaflet
- NHS - Obesity Treatment
- Mounjaro Vs Ozempic: Dosing, Price & Which Is Better?
- Mounjaro Vs Wegovy: The Differences Between Weight Loss Pens
- Mounjaro Vs Saxenda: Side Effects, Differences & Similarities
- Mounjaro Reviews: What Our Customers Think & More
Learn more about Mounjaro side effects and more
While the list of possible Mounjaro side effects may seem concerning, it is important to remember not everyone may experience them, and not all at once. If you have any concerns about Mounjaro’s side effects, talk to your healthcare provider or start a free online consultation with a pharmacist from Cloud Pharmacy.
If we determine Mounjaro is the most suitable weight loss medication for you, we discreetly send it to your UK address. Cloud Pharmacy also provides patient follow-ups and support during their weight loss journeys.
We also stock a range of over-the-counter treatments that can be recommended to help manage the side effects of Mounjaro, if required.
Click here to book a consultation with Cloud Pharmacy.
FAQs
What does Mounjaro do to your body?
Mounjaro works by slowing digestion, reducing appetite, increasing insulin after food, and lowering blood sugar levels.
What can you not take with Mounjaro?
Before taking Mounjaro, talk to your pharmacist or doctor if:
- You have problems with your eyes, such as diabetic retinopathy or macular oedema.
- You have severe problems with food digestion, such as severe gastroparesis.
- You are taking diabetes medication such as sulphonylurea or insulin, as low blood sugar can occur.
- You have had inflammation of the pancreas (pancreatitis).
- You are taking any oral medications. Mounjaro delays gastric emptying, which may impact the absorption of oral medications.
Do not take Mounjaro if you are allergic to tirzepatide or any ingredients listed in the Patient Information Leaflet.
Sources & method
- https://www.nhs.uk/conditions/obesity/
- https://www.cloudpharmacy.co.uk/online-doctor/weight-loss-treatments/#section-treatments
- https://www.cloudpharmacy.co.uk/online-doctor/weight-loss-treatments/mounjaro-weight-loss-injection/
- https://www.medicines.org.uk/emc/files/pil.15481.pdf
- https://www.nhs.uk/conditions/acute-pancreatitis/
- https://www.nhs.uk/conditions/anaphylaxis/
- https://yellowcard.mhra.gov.uk/
- https://www.gov.uk/government/news/mhra-authorises-diabetes-drug-mounjaro-tirzepatide-for-weight-management-and-weight-loss
- https://pi.lilly.com/us/mounjaro-uspi.pdf?s=pi
- https://www.nhs.uk/conditions/thyroid-cancer/symptoms/
- https://uspl.lilly.com/mounjaro/mounjaro.html
- https://www.cloudpharmacy.co.uk/guides/mounjaro-vs-saxenda/
- https://www.nhs.uk/conditions/obesity/treatment/
- https://www.cloudpharmacy.co.uk/guides/mounjaro-reviews/
- https://www.nhs.uk/conditions/dehydration/
