Common side effects and when the leaflets say to seek help

Section 4 of every UK patient information leaflet is headed "Possible side effects". It lists the side effects that have been reported with the medicine, grouped by how often they were reported, and it separates the ones that need urgent help from the rest. This article points to what the Wegovy and Mounjaro leaflets say. It gives no frequencies, because those belong to the leaflet for your own medicine, and it is not a substitute for reading it.

What both leaflets list most often

Both leaflets list digestive effects among those reported most often: feeling sick (nausea), being sick (vomiting), diarrhoea and constipation. The Wegovy leaflet also lists headache, stomach pain and feeling weak or tired among the effects it lists most often. The leaflets describe these in plain words, and each gives its own frequency for each effect. Read yours for the full list.

Fluids

Both leaflets connect vomiting and diarrhoea with losing fluid. The Wegovy leaflet says: "It is important that you drink enough fluids to prevent dehydration. This is especially important if you have kidney problems." The Mounjaro leaflet says that when starting treatment, in some cases you may experience loss of fluids or dehydration, for example due to vomiting, nausea or diarrhoea, which may lead to a decrease in kidney function. If you cannot keep fluids down, the section below on who to contact applies.

When the leaflets say to get help straight away

Each leaflet has a short list of serious effects with an instruction to seek urgent or immediate medical help.

• The Wegovy leaflet says to stop using the medicine and seek urgent medical help for severe, persistent pain in the stomach area, which it says can be a sign of an inflamed pancreas.
• The Mounjaro leaflet lists an inflamed pancreas (acute pancreatitis), which it says could cause severe pain in the stomach and back that does not go away, among the effects that need immediate medical help.
• Both leaflets say to seek immediate medical help for signs of a serious allergic reaction, such as breathing problems or swelling of the face, lips or tongue.

The lists in the leaflets are longer than this, and they are the ones to read.

Who to contact

• 999, or the nearest emergency department, for anything life threatening, including the allergic reaction symptoms above.
• NHS 111, online or by phone, when you need medical help urgently and it is not an emergency.
• Your prescriber, or the pharmacy that dispensed the medicine, for anything about continuing treatment. The leaflets say not to stop using the medicine without talking to your doctor, and the prescriber is the person who can change anything about your treatment.
• Any doctor, pharmacist or nurse for general questions, which is the leaflets' standing advice.

Reporting a side effect

Both leaflets ask you to report any side effect, including one not listed in the leaflet. The Yellow Card scheme, run by the MHRA, takes reports from patients as well as from professionals, and the leaflet gives its web address. The leaflets explain that reporting helps provide more information on the safety of the medicine.

Keeping a record

The symptom log in the Dose Club app records each symptom with a severity from 0 to 3, an appetite score and a note, tagged with the day since your last dose. Dose Insights, in Dose Club Plus, count symptom days per dose period and show which days after a dose your logged symptoms fall on. Both are descriptions of what you logged. The app never interprets a symptom or says whether it is expected, and it never suggests what to do about it. The prescriber PDF puts the record in front of the person who can.

Sources

• Wegovy patient information leaflet, electronic medicines compendium: medicines.org.uk/emc
• Mounjaro patient information leaflet, electronic medicines compendium: medicines.org.uk/emc
• NHS, when to call 999 and when to use 111: nhs.uk
• MHRA Yellow Card scheme: gov.uk

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