What the leaflets say about a missed dose

Every patient information leaflet has a section headed "If you forget to use" the medicine. For Wegovy and Mounjaro the UK leaflets give different rules, the US prescribing information for Wegovy gives a third, and that is the reason the Dose Club app shows you the words of the leaflet for your region and does not work out an answer for you.

The Wegovy leaflet

The UK Wegovy leaflet, published on the electronic medicines compendium, says:

If you forgot to inject a dose and it is 5 days or less since you should have used Wegovy, use it as soon as you remember. Then inject your next dose as usual on your scheduled day. If it is more than 5 days since you should have used Wegovy, skip the missed dose. Then inject your next dose as usual on your next scheduled day.

The Mounjaro leaflet

The UK Mounjaro leaflet, also on the electronic medicines compendium, says:

If it has been 4 days or less since you should have used Mounjaro, use it as soon as you remember. Then inject your next dose as usual on your scheduled day. If it has been more than 4 days since you should have used Mounjaro, skip the missed dose.

If your situation does not fit the rule neatly, the leaflets' standing advice applies to it as to any other question about using the medicine: ask your doctor, pharmacist or nurse.

The regional difference

The two medicines have different rules, and the same medicine can have a different rule in a different country. The US prescribing information for Wegovy frames its rule around the next scheduled dose, using a 48 hour threshold, where the UK leaflet counts the days since the dose was due. A rule copied from a forum or from a friend abroad may be the wrong one for the leaflet in your box.

Why the app shows wording and never a verdict

The missed dose screen in the app shows three things: how many days have passed since the scheduled dose, the leaflet's wording for your region and a link to the leaflet. It does not say "use it" or "skip it". There are two reasons.

The first is accuracy. The leaflet is the document the regulator approved, and it changes from time to time. The app stores the wording per region and links to the source so that you read the current text and not a paraphrase of it.

The second is the line the app does not cross. Software that turns your dates into a dosing instruction is giving dose advice, which the Dose Club app never does. The leaflet gives you the rule, and your prescriber or pharmacist answers anything the rule leaves open.

What the level chart shows

If you log a dose late, the level chart redraws. The estimated amount in your system dips further before the late dose and then climbs, and the curve shows the shape of what happened. That is a description of the doses you logged, built from published figures, and it carries the same reminder as every estimate in the app: "Estimate based on published data. Check with your prescriber before making decisions."

Read your own leaflet

The leaflet in your box is the one that applies to the pen you hold. The electronic medicines compendium carries the current UK version for each strength and shows the date it was last revised. If the wording in the box and the wording online differ, the text has been updated since your box was packed, and your pharmacist can tell you what changed.

Sources

• Wegovy patient information leaflet, electronic medicines compendium: medicines.org.uk/emc
• Mounjaro patient information leaflet, electronic medicines compendium: medicines.org.uk/emc
• Wegovy US prescribing information, Novo Nordisk

This article is information, not medical advice. Talk to your prescriber about your treatment.