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Mounjaro ® ▼ (tirzepatide)
This information is intended for UK registered healthcare professionals only in response to your search for information. For current information for all Lilly products, including Summaries of Product Characteristics, Patient Information Leaflets and Instructions for Use, please visit: www.medicines.org.uk
Modified Mounjaro® (tirzepatide) KwikPen® design
The modified Mounjaro KwikPen presentations will be gradually introduced into the market. Until stock of the initial Mounjaro KwikPen has been exhausted, patients may receive the initial or the modified pen when filling their prescription.
What are the differences between the modified design and initial design?
The initial Mounjaro KwikPen and the modified Mounjaro KwikPen are both disposable multi-dose single-patient-use prefilled pens available in 6 dosages, containing the volume of solution necessary for priming before each injection and the delivery of 4 fixed 0.6mL doses (one dose given weekly).1,2
There are no differences in the functionality of the initial and modified pens. The Instructions for Use for both the initial and modified KwikPens outline identical steps for administering a dose.1
The plunger position in an unused modified Mounjaro KwikPen appears further down in the cartridge than what is seen in the initial device. This is because a new component has been added behind the plunger as depicted in the Mounjaro KwikPen Guide to Parts section of the product’s Instructions For Use (IFU).1,2
The modified KwikPen has a reduced amount of leftover medicine after the delivery of 4 complete doses compared with the initial KwikPen device. In the modified Mounjaro KwikPen, the plunger will appear near the bottom of the cartridge, making it clear to the user that the pen has been completely used and should be discarded.1
Figure 1 description: The modified tirzepatide KwikPen contains a component behind the plunger.
How does the additional component affect the plunger position in an unused pen and after each dose?
The plunger in the modified Mounjaro KwikPen appears further down in the cartridge than in the initial device.1
Following the completion of the 4 fixed 0.6mL doses, the plunger will appear near the bottom of the cartridge, and the amount of leftover medicine will be minimal. This is a normal and the intended outcome of the modified design.1
Figure 3 description: Following the completion of the 4 fixed doses, the plunger positions are approximately as shown in the illustration above.
Is there sufficient medication in the pen to allow for priming before each use?
The initial Mounjaro KwikPen and the modified Mounjaro KwikPen both contain the volume of solution necessary for priming before each injection and the delivery of 4 fixed 0.6mL doses (one dose given weekly).1
References
1Data on file, Eli Lilly and Company and/or one of its subsidiaries.
2Mounjaro [summary of product characteristics]. Eli Lilly Nederland B.V., The Netherlands. (UK)
▼ This medicinal product is subject to additional monitoring. This will allow quick identification of new safety information. Healthcare professionals are asked to report any suspected adverse reactions.
Date of Last Review: 14 October 2025