Mounjaro: what it is used for, dosage and side effects

What Mounjaro is and which active substance it contains

Mounjaro contains the active substance tirzepatide. Unlike the medicines in the older group, tirzepatide acts on two receptors: the GLP-1 receptor and the GIP receptor. Both belong to hormones released by the gut after a meal and both take part in regulating blood sugar and appetite.

In the European Medicines Agency data for the Maltese market the medicine is listed with the active substance tirzepatide and the route of administration: subcutaneous. It comes as a pen for injection under the skin; on the Maltese list it also appears in a pen version under the name Mounjaro KwikPen. It is not a tablet and it is not insulin.

Because the same name covers two authorised situations, it matters which one your own treatment is about. Medicines with a single receptor action are described on /medicines/ozempic/, /medicines/wegovy/ and /medicines/saxenda/, and the group as a whole is set out in /weight-loss-injections/. Comparing them is a medical decision, not a matter of preference.

The strengths, the schedule for stepping up and the storage rules are in the patient information leaflet in your pack. The list of medicines authorised in Malta is kept by the Medicines Authority.

The two authorised situations

In type 2 diabetes the medicine is used in adults when diet and physical activity have not brought blood sugar under satisfactory control. It can be used alone or together with other diabetes medicines, and that combination is what a doctor decides on.

In weight management it is used in adults with obesity, and in adults who are overweight and have at least one weight related condition. There too it is used together with a reduced calorie diet and increased physical activity, not instead of them. What the numbers used to describe weight mean is explained in /health-guide/obesity-and-bmi/, and the symptoms that point to disturbed blood sugar are in /health-guide/type-2-diabetes-symptoms/.

The two situations differ in what a doctor monitors, in which other medicines need adjusting and in what counts as success. Type 1 diabetes and diabetic ketoacidosis are not what this medicine is intended for.

Where a doctor prescribes any medicine outside its authorised use, that is a decision that has to be justified and supervised, and no questionnaire can substitute for it.

How tirzepatide works

Tirzepatide binds to two receptors at once. Through the GLP-1 receptor it increases the release of insulin when blood sugar is raised and reduces the release of glucagon, the hormone that pushes blood sugar up. Through the GIP receptor it acts on the same system from another direction and on the regulation of appetite.

Because the insulin effect depends on the blood sugar level, low blood sugar is not typical when the medicine is used on its own. The risk rises where it is combined with insulin or with a sulfonylurea, and in those combinations a doctor usually lowers the doses of those medicines.

The substance also slows the emptying of the stomach and reduces appetite, so most people eat less during treatment. Slower stomach emptying is at the same time the reason for the digestive complaints that are most common at the start and after each step up.

The action is long lasting, so the medicine is not injected every day. The interval is in the leaflet and is set by a doctor. The full effect builds up while the dose is stepped up, and the result is judged by a doctor from laboratory results and measurements over a longer period.

Dosage and use: what the doctor decides

The starting dose, the pace of stepping up and the dose to aim for are all set by a doctor, and they are not the same in every case. Treatment starts low and rises in steps, which is what makes nausea and the other digestive complaints manageable.

We do not quote strengths, quantities or intervals on this page. They depend on the pack and on the doctor's decision, and they are stated in the patient information leaflet in your pack.

The medicine is injected under the skin and the injection site is changed between doses. Do not share a pen with anyone else, even after changing the needle. Follow the storage and refrigeration rules on the pack.

If an injection is missed, follow the leaflet for your own pack instead of doubling up. After a longer break a doctor may go back to a lower strength, because tolerance falls. In diabetes, stopping treatment on your own means losing control of blood sugar, so a stop or a change of dose is something to agree with a doctor.

Side effects and when to contact a doctor

The most common side effects are digestive: nausea, diarrhoea, vomiting, constipation, indigestion and a feeling of bloating. They are strongest after a step up and settle for most people. Smaller meals, eating slowly and avoiding very fatty food help.

Reduced appetite, tiredness, dizziness, hair thinning and reactions at the injection site are also described. Gallstones and inflammation of the gallbladder are recognised risks, and rapid weight loss adds to them, so pain in the right upper abdomen is a reason to contact a doctor.

Stop the medicine and seek medical help in the case of severe and persistent abdominal pain, especially spreading to the back and with vomiting, or signs of an allergic reaction such as swelling of the face, lips or throat and difficulty breathing. In an emergency in Malta, call 112.

If you have diabetic eye disease, any change in vision during treatment is a reason to contact your doctor rather than to wait. Information on how often each effect occurs is in the patient information leaflet for your pack.

Interactions, alcohol and when the medicine is not suitable

Slower stomach emptying can change how medicines taken by mouth are absorbed. For most of them this has no practical meaning, but a doctor takes it into account for medicines with a narrow margin of safety. Bring a complete list of what you take, including products bought without a prescription, supplements and herbal preparations.

The combination needing most attention is insulin or a sulfonylurea at the same time, because the risk of low blood sugar is then higher and doses often need lowering. Oral contraceptives are worth raising in the assessment as well, since severe vomiting and diarrhoea can reduce how well they are absorbed.

Alcohol changes blood sugar in a delayed way, loads the pancreas and makes worse exactly the complaints that are most common with this treatment. There is no direct incompatibility, but the combination is not neutral, and in diabetes the fall in blood sugar after alcohol often comes during the night.

Before prescribing, a doctor checks for a past inflammation of the pancreas, serious disease of the digestive system, gallbladder disease, advanced diabetic eye disease and a family history of rare thyroid and endocrine disease. Pregnancy, planning a pregnancy and breastfeeding are circumstances to discuss before use.

Prescription status, cover and the price at the pharmacy

Mounjaro is prescription only, so a pharmacy does not supply it without a prescription. The decision to prescribe belongs to a doctor after an assessment of your medical information. We do not sell medicines and we do not ship them.

Whether the medicine is covered by the public health service in Malta, and on what terms, is decided by the health authorities and depends on the situation it is used in. Our service is private and is not covered by them, so the pharmacy price and our fee are two separate items.

The price depends on the pack and on the strength reached and changes over time, so we do not quote it here. A pharmacy will tell you the current amount, and a pharmacy is the only lawful source of supply. Demand for this group of medicines has led to falsified pens being offered outside pharmacies, which is a real risk and not a theoretical one. The relationship between the fee for an assessment and the price of a medicine is explained in /blog/online-prescription-cost-malta/.

What we can do and what the fee covers

Our model is a medical questionnaire that a doctor reviews asynchronously, from your answers and any records you attach. There is no video call, no phone call and no live chat with a doctor. A questionnaire cannot replace a physical examination, so a first prescription for this kind of treatment needs a doctor who examines you and follows you up.

If treatment has already been started by a doctor and this is a continuation, the service depends on which situation your treatment concerns. For continuing treatment of type 2 diabetes the matching service is /repeat-prescription/ for 24,90 €; for continuing treatment authorised in weight management it is /weight-loss/ for 29,90 €. Priority handling is available for an extra 9,90 €, which is not a promise of a deadline.

If the doctor issues a prescription, you receive the document by email as a PDF in the standard EU cross-border format set out in Directive 2012/52/EU; its recognition in another member state is governed by Directive 2011/24/EU. There is no code and the document is not entered in any Maltese state health record, so you go to the pharmacy with a printout or with the PDF on screen, together with photo identification. A pharmacy in Malta may dispense it; the decision rests with the pharmacist, who can refuse, for example where the medicine is not available locally. What a pharmacy checks is set out in /blog/eu-prescription-maltese-pharmacy/, and what to do when a pack runs out in /blog/ran-out-of-medication-in-malta/.

The fee covers the doctor's assessment, not the issuing of a document. If the doctor declines on medical or legal grounds, we refund the fee. If we ask you for medical records, you have at least 7 days to reply. We then send a reminder and extend the deadline on request, and where the assessment still cannot be completed we close the request and refund the fee. The assessment is carried out by Damian Wojno, a doctor registered in Poland, licence no. 3211301, MEDINOW Sp. z o.o. He is not registered with the Medical Council of Malta, which keeps the register of doctors practising here. Narcotic and psychotropic substances are excluded from cross-border prescriptions under Article 11(6) of Directive 2011/24/EU, and tirzepatide is not in that group.