Your Mounjaro pen is finished — here's what to do next

Step 1, Remove the needle and place the pen in a sharps container

The instant your fourth and final dose is given, remove the needle from the pen body using the outer needle cap and place it directly into a sharps container. The pen itself goes in too, it is a single-use medical device and neither the barrel nor the cartridge is refillable. Do not recap the needle with your fingers, and do not place either the needle or the pen into your kitchen bin, bathroom bin or recycling. Tirzepatide cartridges contain residual medicine and a needlestick injury from a used Mounjaro pen carries real risk.

Once your sharps container is around two-thirds full, most local councils and some GP surgeries will accept it for collection or provide a drop-off point, check your local council website for the nearest clinical waste service. The pen's job is done; the container's is just beginning.

If you want a closer look at the mechanics before that final click, the guide on how to take apart a Mounjaro pen walks through the components clearly.

Step 2, Note the date and plan your next injection

Mounjaro is a once-weekly injection, and consistency matters. Missing a dose (or letting days slip between pens) can mean a bumpier return when you restart. The general guidance from the patient information leaflet is that if more than four days have passed since a missed dose, skip it and resume on the next scheduled day. If fewer than four days have passed, take it as soon as you remember. For the exact timing rules that apply to your specific situation, the Mounjaro SmPC on the eMC is the authoritative reference, and your prescriber is always the right person to call if you are uncertain.

A practical detail worth building into your routine: many people keep their current pen in the fridge door so the end of the fourth dose coincides with their weekly shop or a standing calendar reminder. When the pen is empty, the reminder fires and ordering feels routine rather than urgent. Read more about the full injection process on the how to administer your Mounjaro KwikPen page.

Step 3, Arrange your next supply before the gap opens

A finished Mounjaro pen is also a prompt to check your supply. Private prescriptions for tirzepatide require a clinical review before each repeat, that is not a bureaucratic hurdle, it is how safe prescribing works. At nume, a GPhC-registered Independent Prescriber reads your repeat request the same day it arrives; no automated decision, no algorithm standing in. Orders placed before 12pm Monday to Friday are dispatched the same day once clinically approved, arriving free the next working day in plain, unbranded packaging via DPD.

If you are new to treatment and wondering whether tirzepatide is right for you, the Mounjaro overview covers how the medicine works, what the clinical trial evidence shows and who it is licensed for. Already treating elsewhere and thinking of transferring? The process for getting Mounjaro online explains what transfer patients need to provide. And if you have a question about your current prescription before your next pen arrives, the contact and aftercare page is the quickest route to our clinical team.

What the finished pen tells you about your dose and progress

A pen running out on schedule (four doses, four weeks) is the normal pattern. If you are reaching the end of a pen sooner, or if doses seem to be missing, it is worth revisiting the guide to using a Mounjaro pen correctly to make sure the injection technique is right. A common reason doses appear to run out is a failed injection: if the pen did not click fully or was held at the wrong angle, the dose may not have been delivered.

It is also worth raising with your prescriber whether your current strength is still the right one. NICE's guidance on tirzepatide (TA1026) notes that if less than five per cent of body weight has been lost after six months at the highest tolerated dose, continuing treatment should be clinically reviewed. That conversation belongs with your prescriber, not with a finished pen in your hand, but an empty KwikPen is a reasonable prompt to check in on how things are going. Our weight-loss treatment overview sets out the broader context if it helps frame that discussion. When you are ready to arrange your next supply, checking your eligibility with our prescribers is the first step.