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Who needs to know you are on it
Surgery, contraception, other medicines, and the situations where not mentioning it causes an actual problem.
The short version
The situation
You are on a GLP-1 and something else is happening: an operation, a new prescription, a trip.
The short answer
Three things genuinely matter: anaesthetists need to know before any procedure, the contraceptive pill may be affected, and other medicines you take may need adjusting.
The catch
These drugs slow how fast your stomach empties, and that is what links all three. It is not a general 'tell everyone' warning, it is specific and mechanical.
This is a reference, not medical advice. Anything about your own treatment is a conversation with whoever prescribes for you.
01Surgery and anything with sedation
Tell the anaesthetist, and tell them early. A stomach that empties slowly may still contain food after the usual fasting period, and under sedation stomach contents can enter the lungs. That is a serious complication and it is why guidance exists on pausing these medicines before procedures.
This applies to planned operations, and also to endoscopy, dental work under sedation, and anything else where you will be sedated. Say it at the pre-assessment rather than on the day, so there is time to plan. Do not stop the medicine on your own on the assumption that helps: the timing matters and it is a clinical decision.
02Contraception and HRT
NHS England advises using an additional method of contraception, such as condoms, alongside the oral contraceptive pill while taking tirzepatide, because slowed gastric emptying may affect how the pill is absorbed. Similar caution has been advised around HRT, where patches or gels may be preferred over tablets.
This is a genuinely under-communicated point and the consequences of missing it are obvious. If nobody mentioned it when you were prescribed, that is worth a conversation with your pharmacist, who can advise without an appointment.
03Other medicines
- Insulin and sulfonylureas. Combined with a GLP-1 drug, the risk of low blood sugar rises and doses of those may need adjusting by a prescriber. This is the interaction most likely to put someone in hospital.
- Anything where the exact level matters. Slowed gastric emptying can change how oral medicines are absorbed. If you take something with a narrow margin, raise it.
- New prescriptions from anyone. Make sure the GLP-1 is on your record and mention it, " including at walk-in centres and out-of-hours.
Your pharmacist is the most accessible person for this and does not require an appointment. They can check your full list against what you have been given.
04Travel, storage and practicalities
These are prescription medicines and they travel as such. Keep them in the original labelled packaging, carry your prescription or a letter, and check storage requirements in the patient information leaflet, since the injectables have specific temperature requirements and the tablet does not.
Worth knowing that different countries treat these medicines very differently, and something licensed here may not be available or lawful elsewhere. If you are travelling with any medicine, checking the destination country's rules is sensible.
05Who does not need to know
Nobody is entitled to this information because they are curious. Your employer, your relatives and people on the internet are not on the list. There has been a lot of judgemental noise about people using these medicines, and none of it is a reason to tell anyone anything.
The list of people who genuinely need to know is short: anyone prescribing for you, your pharmacist, and anyone about to sedate you.
06Questions worth asking
Take these to your GP, practice nurse, pharmacist or specialist team. The answers are specific to you in a way nothing on this page can be.
- Does anything else I take need adjusting now I am on this?
- Does this affect my contraception, and what should I use alongside it?
- I have a procedure booked. What should I do about this medicine and when?
- Is it on my record so anyone treating me can see it?
07Common questions
Do I need to tell my dentist I am on Mounjaro?
If any sedation is involved, yes, for the same reason as surgery. For routine treatment it is still worth having on your medical history, as it is for anything you take regularly.
Does Mounjaro or Wegovy stop the pill working?
NHS England advises using an additional method such as condoms alongside the oral contraceptive pill, because slowed stomach emptying may affect absorption. Speak to your pharmacist or prescriber, who can advise on your specific situation.
Should I stop before an operation?
That is a decision for the clinical team, and guidance on pausing before procedures exists. Tell them at pre-assessment rather than deciding yourself, because the timing matters.
Can I take it abroad?
It is a prescription medicine, so travel with it in labelled packaging and with evidence of the prescription. Check storage requirements in the leaflet and the destination country's rules on bringing medicines in.
08Sources
- NHS England guidance on tirzepatideNHS England
- Summary of Product Characteristicselectronic medicines compendium
- Drug Safety Update on GLP-1 medicinesMHRA, January 2026
- Medicines and travelNHS
Told when guidance changes
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