It’s pretty straightforward to use Mounjaro weight loss injections: you take one per week, using a new injector pen each month. But there are certain other medications you shouldn’t use at the same time.
Don’t worry, a qualified clinician will check this with you before they prescribe Mounjaro (we certainly will!).
Generally, Mounjaro is safe for most people. But if you are curious about trying it, it’s important to know which other medicines it could interact with—and which you might have to avoid.
Medications that might interact with Mounjaro
What can you not take with Mounjaro? A few medicines are off limits, while there are others that should be used with caution because they could potentially interact with Mounjaro. Always follow your provider’s advice on what you should and shouldn’t take.
Diabetes medications
Mounjaro works by making you feel full, and one way it does that is by simulating the release of insulin when you eat. This also keeps your blood sugar in check.
But some diabetes medicines, like gliclazide and insulin injections, also increase your insulin levels. If you use them alongside Mounjaro, there’s a risk your insulin levels would climb too high and your blood sugar would drop too low (hypoglycaemia).
Birth control pills
Another thing Mounjaro does is slow down your digestion, which keeps you feeling fuller for longer. This might also impact how well oral medications, including birth control pills, can be absorbed once they reach the gut—which means that they might not work as well.
So, the advice is to use a barrier method, like a condom or dental dam, if you’re taking Mounjaro. You could also switch to a long-acting method like the Mirena or copper coil.
Blood pressure medication
There’s evidence that Mounjaro can lower your blood pressure, mostly via the effects of weight loss. For some people, this is good news—but it means that if you’re already taking medication to manage your blood pressure, these effects might overlap. If you fall into that camp, inform your GP that you are starting Mounjaro so they can review your blood pressure plan and increase monitoring until you are stable on treatment.
Thyroid medications
What about Mounjaro and thyroid medication? Mounjaro’s effect on the gut could potentially also affect how well levothyroxine, a tablet for an underactive thyroid, is absorbed. With levothyroxine, even small differences in how much is absorbed can impact its efficacy. So if you’re taking Mounjaro as well, your doctor might want to monitor your thyroid health to make sure that levothyroxine is working as it’s supposed to.
By the way: you shouldn’t use Mounjaro if you or anyone in your family has a history of medullary thyroid carcinoma or if you have multiple endocrine neoplasia syndrome.
Other weight loss medications
Mounjaro should be the only weight loss medicine you’re using at one time.
This is because many of these medicines work in similar ways —for example, by suppressing your appetite—so if you use more than one, their actions can overlap and increase your risk of getting side effects.
Mounjaro and Antidepressants
You can take antidepressants like sertraline, citalopram, or mirtazapine while using Mounjaro. Because Mounjaro slows digestion, it may slightly delay how quickly these medications are absorbed—though this can vary depending on your antidepressant dose, Mounjaro dose, what you’ve eaten that day, and other individual factors.The effect is typically minimal, but if you notice any changes in mood or a decline in mental wellbeing, it’s important to speak to both your Mounjaro provider and your GP.
It’s worth noting that Mounjaro and these antidepressants can share similar side effects—like nausea, diarrhoea and headaches—especially early on, as they all affect gut function and the central nervous system. If symptoms become bothersome, check in with your clinician.
Antidepressants can also increase appetite, so Mounjaro’s appetite-suppressing effects may be especially helpful. By supporting weight loss, it can also contribute to better physical and mental wellbeing.
Herbal medicines and Mounjaro
Here’s the thing: while supplements are herbal medicines, they can still interact with medications like Mounjaro.
There’s no advice to avoid any specific supplements while taking Mounjaro, though the manufacturer’s label notes that Mounjaro-herb interactions haven’t been studied.
Supplements that may affect blood sugar levels include:
• Ginseng: Has been shown to sometimes lower blood sugar in diabetic patients in some studies
• Fenugreek: May help reduce blood glucose levels
If you’re taking either of those to help with your diabetes, it’s best to be safe and tell your provider before trying Mounjaro. Here's a guide if you're wondering which supplements are safe (or even helpful) with Mounjaro.
Antibiotics and Mounjaro
There are no specific antibiotics that you absolutely shouldn’t take with Mounjaro. But since some antibiotics require specific timing with meals or should be taken on an empty stomach, it may be more challenging to manage when taking Mounjaro (since it slows gastric emptying).
If you're prescribed antibiotics while taking Mounjaro, it's best to take them at different times of day. This can help minimise any potential interactions and ensure both medications work as intended.
Both Mounjaro and many antibiotics can cause gastrointestinal side effects, such as diarrhoea. Taking them together may increase the likelihood or severity of these symptoms.
To help manage this:
- Stay well hydrated throughout the day.
- Consider taking a probiotic to support gut health.
- Temporarily reduce high-fibre foods, which may worsen diarrhoea or bloating during this time.
If you experience vomiting or severe diarrhoea, it could affect how your body absorbs Mounjaro. Speak to your healthcare provider; they might recommend adjusting the timing of your doses or temporarily pausing Mounjaro if you're on a short course of antibiotics.
Always check in with your medical team for tailored advice.
Can you take painkillers with Mounjaro?
Yep—you’re fine to take most common painkillers with Mounjaro. There are no warnings against it on the product label. In fact, it says that you can take paracetamol as normal.
Foods to avoid on Mounjaro
Again, there are no rules against eating specific foods while using Mounjaro. Though it is a good idea to avoid those that might hamper your progress (instead, opt for those that are nutritionally rich and will keep you feeling full!)
Foods to avoid include processed foods that are high in sugar, calories, and saturated fats: think crisps, fast food, fizzy drinks, cakes, and other sweets. These foods might give you a rush of energy but you’ll feel hungry again soon after. And they generally don’t offer any real nutritional benefits.
What about alcohol and Mounjaro? It’s a good shout to drink alcohol in moderation, if at all. Alcoholic drinks tend to be high in calories and, if you have a few too many, they can bring on cravings for late-night comfort food.
Always check with your clinician
Mounjaro is a prescription medicine and you should only try to get it from qualified providers.
Online providers like us should be registered as a pharmacy (this information should be on their website—check the footer of this page to see ours), while online doctor services should be registered with the Care Quality Commission (CQC) and General Medical Council (GMC).
Your provider should ask you questions about your current health and medical history, including about any medications you’re taking. Don’t forget to tell them about any supplements you’re using, too.
They’ll weigh all this up when deciding whether you’d benefit from Mounjaro. And if they do write you a prescription, they’ll also tell you how to take the medicine. It is super important that you follow their instructions and stick to the dose they recommended, otherwise you might be more likely to experience side effects.
Starting your journey with Mounjaro
Ready to take the next step in your weight loss journey? Weight loss medications can be a great option if you’ve tried to lose weight another way, but didn’t see the results you hoped for.
Or perhaps you’re already using another one of these medicines, but want to switch to Mounjaro.
We’d be delighted to help in either case. Our clinicians can advise on which medication is best when you sign up to our weight loss programme—or help you safely switch to Mounjaro. Plus, you’ll get one-to-one support from our team of expert coaches, who will help you forge healthy lifestyle habits that last.
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