Tirzepatide - Common brands: Mounjaro

What tirzepatide is for

Tirzepatide is a type of medicine called a GLP-1/GIP agonist. It can be used to manage type 2 diabetes or obesity by helping you lose weight, when combined with exercise and changes to your diet.

Tirzepatide works for weight loss by reducing your appetite and helping you feel fuller for longer. It's a dual agonist that activates the gut hormone receptors GLP-1 and GIP to increase the levels of these hormones in your body.

For type 2 diabetes it works by lowering your blood sugar and helps your body to make more insulin if it's needed. It also slows digestion which keeps your blood sugar levels stable after meals and can help prevent heart disease.

Your doctor may prescribe tirzepatide for type 2 diabetes to control your blood sugar. This is usually before they recommend you use insulin.

You'll usually only be prescribed tirzepatide for weight loss if your BMI meets the eligibility criteria. The criteria depend on whether you get tirzepatide through your doctor or a specialist weight management service.

If you decide to get a private prescription for tirzepatide, it's important to buy it from a registered pharmacy. There are some websites that sell fake weight loss medicines.

How to use tirzepatide

Tirzepatide comes as an injection that you use once a week.

Always check the packet or leaflet that comes with your medicine. It will tell you how to get the injection ready.

Keep your injection in the fridge until you're ready to use it.

Ask a pharmacist or doctor for advice if you're not sure how to use it or you have any problems using it.

When using tirzepatide:

• try to inject on the same day each week – you can change the day as long as it's been at least 3 days since your last injection
• you can have it any time of day
• inject into the fatty areas of your thigh, tummy or the back of your upper arm – ask someone to help you if you want to inject into the back of your upper arm
• change the place you inject each week – you can use the same area but do not use the exact same spot
• inject into a different place if you inject insulin as well

If you miss a tirzepatide injection

If you forget to give yourself a tirzepatide injection and:

• it's 4 days or less since you should have had it, give yourself the injection as soon as you remember
• it's more than 4 days since you should have had it, skip the missed injection

Then continue as usual and give yourself your next injection on your usual day.

Do not give yourself 2 injections at the same time to make up for a missed one.

If you use too much tirzepatide

It's important to get medical advice if you use too much tirzepatide because it can sometimes be dangerous.

How to stop using tirzepatide

Talk to your doctor if you want to stop using tirzepatide, and do not stop suddenly. If you have type 2 diabetes, it could affect your blood sugar.

Your doctor may suggest reducing your dose gradually.

Side effects of tirzepatide

Like all medicines, tirzepatide can cause side effects, but not everyone gets them.

Common side effects

Common side effects of tirzepatide include:

• feeling sick (nausea) or being sick (vomiting)
• constipation or diarrhoea
• stomach pain
• feeling tired
• itchy or red skin where you inject – redness maybe harder to see on brown or black skin
• hair loss

Serious side effects

Tirzepatide can sometimes cause serious side effects, but most of them are rare.

Possible serious side effects of tirzepatide include:

• an allergic reaction (anaphylaxis), which can cause symptoms such as a swollen throat or tongue, a raised, itchy rash or difficulty breathing
• low blood sugar (more likely if used with other diabetes medicines), which can cause headaches, vision problems, feeling dizzy, weak or confused, a fast heartbeat or sweating
• an inflamed pancreas (acute pancreatitis), which can cause severe pain in your stomach or back, which does not go away
• gallstones or swelling of the gallbladder (cholecystitis), which can cause severe tummy pain

If you feel dizzy or have vision problems after using tirzepatide, do not drive, ride a bike or use machinery until you no longer have these side effects.

Who can and cannot use tirzepatide

Most adults can use tirzepatide.

Tirzepatide is not suitable for some people. For example, it may not be suitable if:

• you've had an allergic reaction to tirzepatide or another GLP-1 agonist
• you have or have had an inflamed pancreas (acute pancreatitis)

Before using tirzepatide, tell your doctor or a pharmacist if you have any medical conditions.

Breastfeeding and tirzepatide

Tell your doctor if you're breastfeeding.

Tirzepatide is not used while breastfeeding as it's not known if the medicine passes into breast milk.

Pregnancy and tirzepatide

Tell your doctor if you're pregnant or get pregnant while using tirzepatide.

Tirzepatide is not used during pregnancy as there's not enough information to say it's safe for your baby.

If you want to become pregnant, you should stop using tirzepatide at least 4 weeks before you start trying.

Your doctor will recommend other medicines to treat type 2 diabetes while you’re pregnant.

Find out more about using GLP-1 agonists, including tirzepatide, during pregnancy on the Bumps (Best Use of Medicines in Pregnancy) website

Using tirzepatide with other medicines, food and drink

There are some medicines, herbal remedies and supplements that may not mix well with tirzepatide.

These include:

• other diabetes medicines, such as gliclazide,  glimepiride, metformin and tolbutamide
• some medicines to prevent blood clots, such as warfarin
• insulin – your doctor or specialist nurse may need to adjust your dose
• a general anaesthetic (which puts you to sleep) or a sedative (which relaxes you) for an operation or dental procedure – tell the healthcare professional that you're using tirzepatide

Before you use tirzepatide, tell your doctor or a pharmacist if you're taking any other medicines, herbal remedies, vitamins or supplements.

Tirzepatide and contraception

It’s important to use an additional barrier contraception, such as condoms, a diaphragm or cap for 4 weeks after starting tirzepatide, and for 4 weeks after each dose increase.

Find out more using contraception while taking a GLP-1 agonist on the College of Sexual & Reproductive Healthcare (CoSRH) website

Food, drink and alcohol with tirzepatide

It's best to avoid drinking alcohol while using tirzepatide because it can increase side effects like feeling or being sick (nausea or vomiting).

You’ll need to eat a healthy, balanced  diet while taking this medicine.

Find out more about eating a healthy, balanced diet