Mounjaro Interactions: Medicines and Supplements to Discuss With Your Doctor, Onlinepharmaustralia Mounjaro (tirzepatide) can be prescribed for chronic weight management and type 2 diabetes in appropriate patients. Like any prescription medicine, it is important to tell your doctor or pharmacist about everything you take before starting treatment.
This includes prescription medicines, over-the-counter medicines, vitamins, herbal products and supplements.
Mounjaro can affect blood glucose levels and slows the rate at which food leaves the stomach. As a result, it can affect some medicines or change the way certain medicines work.
Most people do not need to stop their existing medicines when starting Mounjaro. However, some combinations require additional monitoring or a change in treatment.
Which medicines can interact with Mounjaro?
The most important combinations to discuss with your healthcare professional include:
- Insulin
- Sulfonylureas
- Oral contraceptives
- Oral medicines that require careful monitoring
- Other diabetes or weight-management medicines
- Medicines taken before surgery or deep sedation
- Vitamins, herbal products and supplements
The type of interaction depends on the medicine involved.
Mounjaro and insulin
Mounjaro can be used in people with type 2 diabetes who also use insulin, but the combination can increase the risk of hypoglycaemia, or low blood sugar.
Your doctor may need to adjust the insulin dose, particularly when starting Mounjaro or increasing the dose.
Symptoms of low blood sugar can include:
- Shaking
- Sweating
- Hunger
- Dizziness
- Weakness
- Confusion
- A fast heartbeat
If you use insulin and are prescribed Mounjaro, do not change your insulin dose yourself. Follow the treatment plan provided by your healthcare professional.
Mounjaro and sulfonylureas
Sulfonylureas are another group of medicines used to lower blood glucose. Examples include gliclazide and glimepiride.
Taking Mounjaro with a sulfonylurea can increase the risk of hypoglycaemia. Your prescriber may consider reducing the sulfonylurea dose and may recommend closer blood glucose monitoring.
This does not mean that Mounjaro and sulfonylureas can never be used together. The combination simply requires appropriate medical supervision.
Mounjaro and metformin
Metformin is commonly used to treat type 2 diabetes and may be prescribed alongside other diabetes medicines.
There is not a general rule that metformin must be stopped when someone starts Mounjaro. Whether the combination is appropriate depends on the individual’s diabetes treatment plan, blood glucose levels, kidney function and other factors.
If you already take metformin, tell your prescriber before starting tirzepatide.
Do not stop or reduce metformin without medical advice.
Mounjaro and oral contraceptives
This is an important interaction to understand.
Mounjaro slows gastric emptying, which can affect the absorption of medicines taken by mouth. The Australian Product Information specifically includes a warning about oral hormonal contraceptives.
The TGA advises people taking oral hormonal contraceptives to switch to a non-oral contraceptive method or add a barrier method for 4 weeks after starting Mounjaro and for 4 weeks after each dose escalation.
If you take the contraceptive pill, discuss your options with your doctor or pharmacist before starting tirzepatide.
Do not assume that your usual oral contraceptive provides the same level of protection during these periods.
Mounjaro and other oral medicines
Mounjaro delays gastric emptying. This effect is strongest around treatment initiation and can also be relevant following dose increases.
For many oral medicines, this is not expected to cause a clinically meaningful problem. However, extra care may be needed with medicines that:
- Have a narrow therapeutic index
- Need precise blood concentrations
- Depend on rapid absorption
- Are modified-release or slow-release medicines
- Require close monitoring
The Australian Product Information specifically identifies medicines with a narrow therapeutic index, such as warfarin and digoxin, as examples where monitoring may be appropriate, particularly when starting tirzepatide or increasing the dose.
If you take an important long-term medicine by mouth, give your doctor or pharmacist the exact name and dose.
Mounjaro and warfarin
Warfarin is an example of a medicine with a narrow therapeutic index.
Because tirzepatide can affect gastric emptying, the Australian Product Information recommends monitoring people taking oral medicines with a narrow therapeutic index, particularly during the early stages of treatment and after dose increases.
If you take warfarin, your healthcare professional can determine whether additional monitoring is necessary.
Do not change your warfarin dose without medical advice.
Mounjaro and digoxin
Digoxin is another medicine with a narrow therapeutic index.
People taking digoxin should tell their doctor before starting Mounjaro. Because tirzepatide can alter the rate at which oral medicines are absorbed, your healthcare professional may decide that monitoring is appropriate, particularly when treatment begins or the Mounjaro dose is increased.
Mounjaro and other GLP-1 medicines
Mounjaro should not be combined with another GLP-1 receptor agonist or another medicine containing tirzepatide unless specifically directed by a healthcare professional.
For example, do not switch between Mounjaro, Ozempic, Wegovy or another GLP-1 medicine on your own.
Although these medicines are used for related conditions, they contain different active ingredients and have different prescribing considerations.
If your doctor recommends changing from one medicine to another, they can tell you when to stop the existing treatment and when to start the new one.
Mounjaro and other weight-loss medicines
Weight-management medicines should not automatically be combined with Mounjaro.
Some combinations may increase side effects or may not have been adequately studied. Your doctor should review your complete treatment plan before another weight-loss medicine is added.
This is particularly important if the other medicine also affects appetite, blood glucose, gastrointestinal function or body weight.
Mounjaro and vitamins or supplements
There is no blanket rule that vitamins or dietary supplements must be avoided with Mounjaro.
However, you should still tell your doctor or pharmacist about all supplements you take.
This includes:
- Multivitamins
- Protein supplements
- Herbal products
- Traditional medicines
- Weight-loss supplements
- Sports supplements
- Products purchased online
The Australian Consumer Medicine Information advises patients to tell their doctor or pharmacist about medicines, vitamins and supplements purchased without a prescription.
The fact that a supplement is described as “natural” does not automatically mean it is safe to combine with prescription medicine.
Mounjaro and alcohol
Alcohol is not simply a standard drug interaction with tirzepatide, but drinking alcohol while taking Mounjaro can be relevant to your treatment.
Alcohol can contribute to dehydration and may make gastrointestinal symptoms such as nausea or vomiting harder to manage. For people taking insulin or certain diabetes medicines, alcohol can also affect blood glucose control.
If you drink alcohol regularly, discuss this with your healthcare professional.
Mounjaro and medicines before surgery
Mounjaro slows gastric emptying. This is important before general anaesthesia or deep sedation because food may remain in the stomach for longer than expected.
The TGA has required warnings for GLP-1 and related medicines about the potential risk of stomach contents entering the airway during general anaesthesia or deep sedation. Patients taking Mounjaro should tell their healthcare professionals, including their anaesthetist, before surgery or a procedure involving deep sedation.
Do not stop Mounjaro before a procedure unless your healthcare team tells you to do so.
What about antibiotics?
There is no general rule that antibiotics cannot be taken with Mounjaro.
Whether an antibiotic is suitable depends on the specific medicine, your health condition and your other treatments.
If you are prescribed an antibiotic while taking Mounjaro, tell the prescriber that you use tirzepatide and provide your complete medication list.
What about antidepressants?
Many people take more than one prescription medicine, and there is no blanket rule that antidepressants cannot be used with Mounjaro.
However, individual medicines can have their own precautions and interactions. Your doctor or pharmacist should review the exact antidepressant, dose and other medicines you take.
Do not stop an antidepressant suddenly simply because you have started Mounjaro.
What about blood pressure medicines?
Blood pressure medicines are not automatically incompatible with Mounjaro.
However, weight loss, reduced food intake, vomiting, diarrhoea or dehydration can affect blood pressure and fluid balance.
If you experience dizziness, fainting, unusually low blood pressure or significant dehydration, contact your healthcare professional.
Your doctor may need to review your treatment if your health or weight changes significantly.
Does Mounjaro interact with every medicine?
No.
Mounjaro does not mean that every medicine you take will interact with tirzepatide.
The Australian Product Information states that the effect on the absorption of oral medicines is generally not expected to be clinically meaningful for medicines without a narrow therapeutic index. However, medicines with a narrow therapeutic index and medicines requiring rapid absorption deserve particular attention.
This is why giving your doctor a complete medication list is more useful than assuming that a particular category of medicine is always safe or unsafe.
What should you tell your doctor before starting Mounjaro?
Before your first dose, provide a complete list of everything you take.
Include:
Prescription medicines
Give the name, strength and how often you take each medicine.
Over-the-counter medicines
Include painkillers, cold medicines, antacids and other pharmacy products.
Vitamins and supplements
Include herbal and traditional medicines.
Contraception
Tell your healthcare professional if you use an oral contraceptive.
Diabetes medicines
Especially tell your doctor if you use insulin or a sulfonylurea.
Medicines requiring regular blood tests
Examples include medicines such as warfarin where monitoring may be required.
Upcoming procedures
Tell your healthcare team if you are scheduled for surgery, general anaesthesia or deep sedation.
Can I stop a medicine when I start Mounjaro?
No.
Do not stop prescription medicines simply because you have started Mounjaro.
Some medicines may need their doses adjusted, but this should be decided by your doctor or pharmacist. Mounjaro interactions
This is particularly important for insulin, sulfonylureas, anticoagulants and medicines used to manage chronic conditions.
When should you contact a healthcare professional?
Contact your healthcare professional if you:
- Start taking a new prescription medicine
- Start an over-the-counter medicine or supplement
- Are prescribed insulin or a sulfonylurea
- Take an oral contraceptive
- Are scheduled for surgery or deep sedation
- Experience repeated low blood sugar
- Have persistent vomiting or diarrhoea
- Become significantly dehydrated
- Notice unexpected changes in the effect of another important medicine
Seek urgent medical attention for severe symptoms, including severe allergic reactions, severe or persistent abdominal pain, severe dehydration or sudden loss of vision. Mounjaro interactions
The TGA has also updated tirzepatide safety information concerning rare non-arteritic anterior ischaemic optic neuropathy (NAION). Sudden loss of vision should prompt urgent ophthalmological assessment. Mounjaro interactions
Frequently Asked Questions
Can I take Mounjaro with my other medicines?
Possibly. Many medicines can be used alongside Mounjaro, but your doctor or pharmacist should review your complete medication list before treatment begins.
Does Mounjaro interact with metformin?
Mounjaro and metformin may be used together in appropriate people with type 2 diabetes. Your prescriber should determine whether the combination is suitable for you. Mounjaro interactions
Can I take Mounjaro with insulin?
Yes, but the combination can increase the risk of low blood sugar. Your healthcare professional may need to adjust your insulin dose.
Does Mounjaro affect birth control?
Mounjaro may reduce the effectiveness of oral hormonal contraception during treatment initiation and dose escalation. The TGA recommends a non-oral contraceptive or an additional barrier method for 4 weeks after starting Mounjaro and for 4 weeks after each dose increase. Mounjaro interactions
Can I take vitamins with Mounjaro?
There is no general requirement to avoid all vitamins, but tell your doctor or pharmacist about every vitamin, supplement and herbal product you use.
Can I take Ozempic and Mounjaro together?
Do not combine or switch between these medicines without medical advice. Your prescriber should determine the appropriate treatment plan.
Should I tell my anaesthetist that I take Mounjaro?
Yes. Tell your anaesthetist and other healthcare professionals before general anaesthesia or deep sedation because Mounjaro can delay gastric emptying.
The Bottom Line
Mounjaro does not automatically conflict with every medicine, but certain combinations require particular attention.
The most important points are to tell your healthcare professional about all prescription medicines, over-the-counter products, vitamins and supplements you use. Mounjaro interactions
Insulin and sulfonylureas can increase the risk of low blood sugar when combined with Mounjaro. Tirzepatide can also affect the absorption of some oral medicines because it slows gastric emptying. Oral contraception requires special attention during treatment initiation and dose escalation. Mounjaro interactions
If you are unsure whether Mounjaro is compatible with something you take, do not guess. Ask your doctor or pharmacist before making changes to your medication.