Independent UK medicine guidance
When to contact your Mounjaro prescriber, and when it is 111 or 999
Most online pharmacies that prescribe Mounjaro (tirzepatide) have a messaging service and a clinical team, and most people never use it. This page sets out what the prescriber is for, what belongs with your GP, what needs NHS 111, and the short list of symptoms that need 999 or A&E. It is built from the UK leaflet, so the urgent lines are the manufacturer’s, not ours.
Who does what
Your prescriber (the pharmacy or clinic that issued the Mounjaro) is responsible for the prescription. They decide dose, titration timing, whether to hold a dose, and whether treatment is still appropriate. Side effects, dose questions and anything that makes you reluctant to inject go to them first.
Your GP holds your full record. Anything that could be another condition, that needs a blood test, an examination or a referral, or that concerns your mood, belongs with your GP. Tell your GP you are taking Mounjaro if you have not already; our guide to informing your GP explains why.
NHS 111 is for urgent problems that are not emergencies, and for anything worrying when your prescriber is closed. Most online pharmacies close at weekends.
999 or A&E is for the emergencies the leaflet names, listed above and detailed below.
Symptom by symptom
The table follows the UK leaflet’s own escalation wording where it exists. It cannot diagnose anything; if a symptom is not here, or you are unsure, use 111.
| What you notice | Contact | Why |
|---|---|---|
| Severe, persistent pain in the stomach area, with or without nausea and vomiting | Stop Mounjaro and seek urgent help: 999 or A&E | Leaflet wording for possible acute pancreatitis.[1] Pancreatitis guide |
| Swelling of face, lips, tongue or throat; difficulty breathing or swallowing; very fast heartbeat with rash | 999 | Serious allergic reaction.[1] Allergic reaction guide |
| Severe pain in the upper right abdomen, fever, yellowing of skin or eyes | 999 or A&E | Possible gallbladder problem; the leaflet asks you to tell a doctor.[1] Gallstones guide |
| Cannot keep fluids down, repeated vomiting, dark urine, dizziness, very little urine | NHS 111 (999 if collapsing or confused) | Dehydration can affect the kidneys.[1] Kidneys guide |
| Stomach pain lasting more than 30 minutes, or returning | NHS 111 | Stomach pain guide |
| Shaking, sweating, confusion (if you also take insulin or a sulphonylurea) | Treat the low then tell your prescriber; 999 if unconscious | Low blood sugar risk with those medicines.[1] Low blood sugar guide |
| Thoughts of harming yourself | 999 if you may act; otherwise 111 mental health option, GP, or Samaritans 116 123 | Mood guide |
| Nausea, constipation, diarrhoea, reflux, tiredness that is persistent, worsening or stopping you eating or drinking | Prescriber | They can review dose and titration. Nausea guide |
| Side effects got noticeably worse after a dose increase | Prescriber, before your next step up | Dose changes are the prescriber’s decision.[1] |
| Feeling sick at the thought of injecting, or reluctant to take the next dose | Prescriber | Sick at the thought of injecting |
| Missed a dose and unsure what to do | Check the leaflet rule, then prescriber if still unsure | The leaflet gives a time window for a late dose.[1] KwikPen guide |
| Planned surgery or a procedure under sedation | Tell the surgical team and your prescriber in advance | Surgery guide |
| Pregnant, planning pregnancy or breastfeeding | Prescriber and GP now | Not for use in pregnancy; stop at least a month before trying to conceive. Breastfeeding is a prescriber judgement.[1] Pregnancy guide |
| Low mood, flatness, poor sleep, hair shedding, headaches, period changes | GP (and tell your prescriber) | Often not the medicine; needs a wider look. Symptom map |
| Any side effect you want on the record | Yellow Card | MHRA scheme for reporting suspected side effects.[3] |
How to message your prescriber so you get a useful answer
Clinical teams answer faster and better when the message has the facts they need. Include: your current dose and how many weeks you have been on it, when the symptom started, how bad it is out of 10, whether it is before, after or between doses, any vomiting, how much fluid you are managing, and any other medicines. Ask a specific question: should I take my next dose on time, stay at this dose, or be seen?
Template: “I am on [dose] mg, week [n]. Since [date] I have had [symptom], about [n]/10, mainly [before/after/between] doses. I [have/have not] vomited and am managing [fluid]. My next dose is due [day]. Should I take it as planned, and is there anything you want to change?”
What your prescriber can and cannot do
- They can hold your next dose, keep you at a dose for longer, or slow the titration. The leaflet leaves dose changes to the prescriber, not the patient.[1]
- They can review whether another medicine or condition is contributing.
- They cannot examine you or run tests remotely. Anything that needs hands or bloods goes to your GP or 111.
- They cannot advise on emergencies in real time. Do not message about severe stomach pain; call.
Common questions
Should I contact my GP or my Mounjaro pharmacy?
The pharmacy that prescribed it for anything about the prescription itself: dose, side effects, whether to take the next dose. Your GP for anything that could be another condition, needs a test, or concerns your mood.
My online pharmacy is closed and I feel unwell. What do I do?
Use NHS 111 online or by phone. If you have any of the 999 symptoms above, call 999. Do not wait for Monday.
When should I stop taking Mounjaro?
The leaflet tells you to stop and seek urgent help for severe, persistent stomach pain that may signal pancreatitis. Otherwise, stopping or pausing is a decision to make with your prescriber, not something to do on your own after reading a webpage.
Should I report side effects to the MHRA?
Yes if you suspect a side effect, especially one that is not in the leaflet. The Yellow Card scheme is how the regulator spots new safety signals, and it takes a few minutes online.
All side-effect guides
About this page. Monj is an independent information and price comparison service run by Medstack Ltd. It is not a pharmacy and does not prescribe, dispense or sell medicines. This page provides general information, not diagnosis or individual medical advice. It has not been clinically reviewed; a named clinical reviewer will be added when one has approved it. Read our editorial and review policy and independence statement.
References
- Eli Lilly. Mounjaro KwikPen: Package leaflet, information for the patient (UK), revised August 2026. electronic medicines compendium. medicines.org.uk/emc/product/15481/pil. Accessed 6 September 2026.
- NHS. When to use NHS 111. nhs.uk. Accessed 6 September 2026.
- MHRA. Yellow Card scheme. yellowcard.mhra.gov.uk. Accessed 6 September 2026.
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© 2026 Medstack Ltd. Written and published by Monj (monj.co.uk). You are welcome to link to this page or quote a short extract with a credit and a link. Republishing the text, page structure, safety-routing design or price data, in whole or in part, including to train or ground an automated system, is not permitted without written permission. See our independence statement and editorial and review policy.
