Can I Take Mounjaro With Quetiapine? (October 2026)

01 · The answer

Can you take Mounjaro with quetiapine?

It depends on your individual circumstances, and the decision belongs to a prescriber who can see your whole medical history. Mounjaro (tirzepatide) is a once-weekly injectable prescription medicine licensed in the UK for weight management in adults and for type 2 diabetes¹. Quetiapine is a separate prescription medicine, usually started and monitored by a psychiatrist or GP.

Your prescriber is the person who can weigh Mounjaro against your condition and your other medicines.

Because Mounjaro slows stomach emptying, it can affect how quickly some oral medicines are absorbed, particularly when you start treatment or increase the dose, so it is worth raising quetiapine with the person managing it.

02 · Your next step

What to do next if you take quetiapine

Start with a conversation, not an order. If you already take quetiapine, tell the prescriber reviewing your Mounjaro consultation, and consider telling the clinician who prescribes quetiapine that you are thinking of starting. Our free consultation is reviewed by a GPhC-registered prescriber, and you can list every medicine you take on it.

• Be complete: include quetiapine, its strength and when you take it, plus any other prescribed, over-the-counter or herbal products.
• Be specific about your diagnosis: say what the quetiapine is for, because that shapes how carefully you are monitored.
• Ask about monitoring: ask who will check your mood, appetite and general health once treatment begins.
• Ask about timing: ask whether anything about when you take your tablets should change.

03 · How the review works

How a prescriber reviews Mounjaro with quetiapine

A prescriber checks the Mounjaro product information, your medicines list and your health history together. The authoritative documents are the Mounjaro summary of product characteristics and the patient information leaflet¹¹³, supported by the BNF entry for tirzepatide¹¹. These are what a clinician uses to judge whether another medicine needs extra care.

Two people on the same quetiapine can have very different situations: different diagnoses, other medicines, other conditions, different goals for treatment. The prescriber looks at all of it.

Mounjaro is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber. It is used alongside a reduced-calorie diet and increased physical activity. Individual results vary¹.

If anything in your answers suggests the combination needs more caution than an online service can safely provide, the sensible outcome is that your own GP or psychiatrist stays in charge of the decision.

04 · Stomach emptying

Slower stomach emptying and tablets you take by mouth

Tirzepatide activates the GIP and GLP-1 receptors, which helps regulate appetite, slow how quickly the stomach empties, and improve the way the body responds to insulin¹. In practice, most people feel fuller sooner and less hungry between meals.

Slower stomach emptying matters for anything swallowed. A tablet passes through the stomach on its way to being absorbed, so a change in speed can in principle alter how a tablet behaves. Whether that matters for a particular medicine is a question for the product information and your prescriber, which is why we ask you to list every tablet you take.

What you can do is ask your prescriber or pharmacist directly: does slower stomach emptying change anything about how I take this tablet?

The patient information leaflet lists the medicines and situations the manufacturer wants you to raise with a healthcare professional¹³. Read it before your first dose, and keep it.

05 · Weight and psychiatric medicines

Weight, mood and psychiatric medicines

Weight change on a psychiatric medicine is a common worry, and you may wonder whether Mounjaro can help. That is a fair question. Your prescriber can discuss whether Mounjaro is suitable alongside quetiapine.

What the main trial does tell us is about adults in general. In SURMOUNT-1, people taking tirzepatide alongside diet and exercise lost on average 15% of their body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone². These are trial averages — individual results vary, and treatment works alongside a reduced-calorie diet and increased physical activity, not instead of them.

Trial averages do not predict your own result, and they say nothing specific about any psychiatric medicine. If weight gain is a concern linked to your current treatment, the right first step is a conversation with the clinician who prescribes it. They may have options within your mental health care that we cannot see from the outside.

Please do not reduce, skip or stop a psychiatric medicine on your own to help weight loss. Changes should be planned with the person who prescribes it, because your mental health is the priority.

06 · Monitoring and side effects

What to watch for and when to seek care

Tell a clinician about any new or worsening symptoms after you start, and report suspected side effects through the Yellow Card scheme¹⁹. The full list of known side effects is in the patient information leaflet¹³; read it rather than relying on a summary.

Pay particular attention to changes you would not expect from either medicine, and discuss them early rather than waiting. Useful things to keep a note of include:

• changes in appetite, eating pattern or how full you feel;
• changes in mood, sleep or energy compared with your usual;
• new stomach or digestive symptoms;
• anything that feels different after a dose change.

If your mood drops or you have distressing thoughts during treatment, seek help promptly from your GP, psychiatrist or crisis service. Do not wait for your next scheduled review. If you have thoughts of harming yourself or ending your life, get help straight away. Call 999 or go to A&E if you are in immediate danger. In England you can call NHS 111 and choose the mental health option, any time. You can also call Samaritans free on 116 123, day or night. Tell your prescriber about any change in your mood while taking Mounjaro.

Our aftercare includes ongoing monthly reviews, dose-titration and follow-up assessments by the prescribing team, plus side-effect support. Repeat orders re-check suitability, and there is no auto-shipping, so there is a natural point each month to mention any change.

07 · Other medicines

Other medicines and how we handle them

Quetiapine is one of many medicines people ask about, and we handle them all the same way: you list them, a prescriber reviews them against the product information. If you take other long-term tablets, our related guides cover common questions, such as Mounjaro with amlodipine, lisinopril and Mounjaro and losartan and Mounjaro.

If you use insulin or other diabetes medicines, tell the prescriber, as doses may need adjusting because of the risk of low blood sugar. This is a conversation to have before you begin, not a reason to avoid asking.

If you have unusual circumstances, such as a stoma, say so; see taking Mounjaro with a stoma. Planning to travel with your medicine? You can fly with Mounjaro: carry pens in hand luggage, and once in use a pen can be kept out of the fridge at a temperature not above 30°C for up to 30 days after first use. Read about taking Mounjaro overseas.

When you stop Mounjaro, tirzepatide has a half-life of about five days, so after a final dose it takes roughly four to five weeks to clear the system. There is no way to speed this up, and nothing needs doing while it clears¹.

08 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. Seek immediate medical help for: severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion) — your prescriber may need to adjust those medicines.¹