What medicines should you not take with Wegovy?

You open the medicine cabinet before your first injection

Picture the scene: your Wegovy pen has arrived, it is sitting in the fridge door, and you are reading the leaflet. You glance at the shelf of other medicines you take every morning (a blood pressure tablet, a contraceptive pill, maybe a statin) and wonder whether any of them are a problem. It is a good instinct. Semaglutide, the active ingredient in Wegovy, slows the rate at which the stomach passes food and liquids into the small intestine. That same mechanism can delay or reduce the absorption of oral medicines taken around the same time, meaning plasma concentrations may be lower or reach their peak later than expected. This is not a reason to panic; it is a reason to have a proper conversation with your prescriber before starting, and our guide covering what not to take with Wegovy is a good place to begin that preparation. The NHS medicines page for semaglutide lists the most common interaction groups clearly, and it is a useful starting point.

The interaction concern is not unique to Wegovy. It applies across the GLP-1 medicine class, though the degree varies. Wegovy's 2.4 mg weekly dose sits at the upper end of the semaglutide range, which is worth bearing in mind when your prescriber weighs the risks.

Diabetes medicines: the interaction that matters most clinically

If you already take medication for type 2 diabetes (particularly insulin or a sulfonylurea such as glibenclamide or gliclazide) adding Wegovy raises the risk of hypoglycaemia (blood sugar falling too low). Semaglutide reduces appetite and lowers blood glucose independently; stacked on top of medicines that already reduce glucose, the combined effect can push levels further than intended. Your diabetes team or prescriber will usually reduce the dose of the existing medicine before or shortly after Wegovy begins, rather than leaving both at their original levels. Signs of hypoglycaemia (shakiness, sweating, confusion, a racing pulse) need prompt attention. The British National Formulary entry for semaglutide lists these interaction signals in clinical terms; your prescriber works from exactly this kind of reference. It is also worth reading about the conditions that make Wegovy unsuitable for some people, which overlaps with the interaction picture.

Metformin, by contrast, does not carry the same low-blood-sugar risk when combined with semaglutide, because metformin on its own rarely causes hypoglycaemia. Still, any change to a diabetes regimen should go through the prescriber managing that condition.

Oral contraceptives and narrow-therapeutic-window medicines

Because Wegovy slows gastric emptying, it can delay how quickly an oral contraceptive tablet is absorbed. The practical upshot is that hormonal contraception taken by mouth may be slightly less reliably absorbed in the early weeks of treatment, particularly at the start of treatment and after each dose increase. NHS England's guidance on weight-management injections suggests women using the pill add a non-oral contraceptive method during this period, condoms are the simplest backup. The tirzepatide SmPC makes this explicit with a four-week rule; semaglutide guidance is more cautious but less prescriptive, so a direct conversation with your GP or prescriber is the right call. You can read more about Wegovy alongside blood pressure medicines in a separate guide, but the short version is that antihypertensives generally do not carry a direct pharmacological clash, the main watch-point is monitoring blood pressure as weight falls, because the medicine's dose requirement may change.

Medicines with a narrow therapeutic window are the other group requiring real attention. These include warfarin (the anticoagulant), certain antiepileptics such as phenytoin, and some thyroid medicines. A small shift in absorption timing can push the drug's level outside its target range. If you take warfarin, your INR should be monitored more frequently at the start of Wegovy treatment. The same logic applies to levothyroxine: many people take it first thing in the morning on an empty stomach, which is already optimal for absorption, but noting the timing matters more once semaglutide is in the mix.

The broader rule: bring the full list

There is no single banned-medicine list for Wegovy, most interactions are about timing and dose adjustment rather than absolute incompatibility. What that means practically is that the interaction check is only as good as the information provided. At nume, every consultation is reviewed by a GPhC-registered Independent Prescriber who reads your answers the same day, including your current medicines. Nothing is rubber-stamped by software. If your prescriber identifies a potential interaction, they may ask for more detail, recommend a timing adjustment, or suggest speaking to your GP before proceeding. That is the process working as it should. You can explore how semaglutide works as a medicine for broader background, or read our guide to deciding whether Wegovy is right for you if you are still at the weighing-it-up stage. Supplements, herbal remedies and over-the-counter NSAIDs like ibuprofen are worth mentioning too, they are commonly forgotten but part of a complete picture. If you have questions about a specific combination not covered here, our team is reachable through the contact page. Once you are ready to take the next step, a free consultation is the place to start, no commitment, no hidden fees.