Incorrect use of Mounjaro pens in obesity treatment
Incorrect use of Mounjaro pens in obesity treatment
The Belgian Federal Agency for Medicines and Health Products (FAMHP) has received reports of incorrect use of pre-filled tirzepatide pens in the treatment of obesity.
In some cases, one pre-filled pen containing 4 doses of tirzepatide is being used to administer 8 half-doses, for example 8 doses of 2.5 mg instead of the intended 4 doses of 5 mg.
In addition, some patients attempt to recover the residual liquid remaining in the pen as an “extra” dose, also referred to on social media as the “golden dose.” Patients recover this “extra” dose by, for example, opening the pen and using an insulin syringe.
One explanation for this misuse is that patients are trying to reduce costs, since tirzepatide is not reimbursed for the indication of obesity. Similar practices are also suspected with other GLP-1 analogues used for obesity treatment, where some patients attempt to obtain more doses in order to save money.
The FAMHP strongly advises against these practices. Dose accuracy cannot be guaranteed, creating a risk of underdosing or overdosing. Furthermore, there is a potential risk of infection when needles are reused multiple times, when the pen is opened and another syringe is used to recover residual liquid, and when the maximum storage or usage period is exceeded.
The SmPCs (Summaries of Product Characteristics) provide clear instructions:
SmPCs for tirzepatide and semaglutide:
Do not recover residual liquid: there is not enough remaining for an additional dose.
Respect the storage conditions and shelf life:Mounjaro: after first use, the pen may be used for a maximum of 30 days and stored at room temperature.Wegovy: after first use, the pen may be used for a maximum of 6 weeks and stored either at room temperature or in the refrigerator.
Always use a new needle for each injection (to prevent infections and needle blockage).
SmPC for liraglutide:
Respect the storage conditions and shelf life:Saxenda: after first use, the pen may be used for a maximum of 1 month and stored either at room temperature or in the refrigerator.
Always use a new needle for each injection (to prevent infections and needle blockage).
Which products are concerned?
Tirzepatide product indicated for obesity:Mounjaro (4 doses per pre-filled pen)
Semaglutide product indicated for obesity:Wegovy (4 doses per pre-filled pen)