How to Use Mounjaro: Step-by-Step Injection Guide
Mounjaro (tirzepatide) is a once-weekly injectable medicine licensed in the UK for type 2 diabetes and for weight management in eligible adults. If you are looking for how to prime a Mounjaro pen, the answer is that priming is a required step: the UK Instructions for Use covers it as steps 7 to 9, and its purpose is to clear air from the cartridge and confirm the pen is working. In the UK, Mounjaro is supplied as a KwikPen, a multi-dose pre-filled pen holding four fixed weekly doses, operated with a dose knob and a dose window, and used with a pen needle you attach yourself. This guide follows the UK Instructions for Use, patient leaflet and Summary of Product Characteristics, and is a summary rather than a replacement for the booklet supplied with your pen.
Summary: The Mounjaro KwikPen is primed before each injection. Turn the dose knob until you hear two clicks and the extended line shows in the dose window, hold the pen with the needle pointing up and tap the cartridge holder to collect air bubbles, then push the dose knob in and hold for five seconds, releasing medicine into the air rather than into your body.
- Priming is steps 7 to 9 of the UK Instructions for Use, and removes air from the cartridge while confirming the pen works.
- The pen has primed if a small amount of medicine appears at the needle tip; if not, repeat up to twice more, then change the needle and try once more.
- Always fit a new pen needle for each injection. Needles are not included in the pack.
- Each KwikPen holds four fixed doses, one weekly, and is discarded after the fourth dose or 30 days after first use, whichever comes first.
- Do not store the pen with the needle attached, because it lets air enter the cartridge.
Table of Contents
How to Prime a Mounjaro KwikPen
Yes, the Mounjaro KwikPen is primed before each injection. Priming is steps 7 to 9 of the Instructions for Use supplied with your pen, and the leaflet states its purpose plainly: priming removes air from the cartridge and makes sure the pen is working correctly.
The three steps, once you have attached a new pen needle and removed both needle shields:
- Find the prime position. Slowly turn the dose knob until you hear two clicks and the extended line shows in the dose window. That is the prime position. If you overshoot, you can turn the dose knob in either direction until the prime position lines up with the dose indicator.
- Collect the air bubbles. Hold the pen with the needle pointing up and tap the cartridge holder gently, so any air collects at the top.
- Release medicine into the air. Push the dose knob in until it stops, then slowly count to five while still holding the knob. Do not inject this into your body. The pen has primed successfully if a small amount of medicine appears at the tip of the pen needle.
If no medicine appears. The Instructions for Use gives a specific, bounded sequence rather than leaving you to keep trying: repeat steps 7 to 9 no more than two further times. If you still see no medicine, fit a new pen needle and repeat steps 7 to 9 once more. If there is still nothing, stop and contact your local Lilly affiliate, or speak to your doctor, pharmacist or nurse.
The Instructions for Use booklet in your carton is the authority on this, and the leaflet asks you to read it before your first injection and again each time you start a new pen, because the information can change. The summary here does not replace it.
Preparing Your Mounjaro KwikPen Before Priming
Priming comes after preparation, not before it. The Instructions for Use lists what you need: your Mounjaro KwikPen, a KwikPen compatible pen needle, a swab, gauze or a cotton ball, and a sharps disposal container. Needles are not included in the pack, so check with your doctor, pharmacist or nurse which needle to use with your pen.
Wash your hands with soap and water.
Pull the pen cap straight off, then inspect the pen and its label. Do not use the pen if the medicine name or dose strength does not match your prescription, if the pen is past its expiry date or looks damaged, or if the medicine has been frozen, has particles in it, or is cloudy or discoloured. Mounjaro should be colourless to slightly yellow.
Wipe the red inner seal with a swab.
Fit a new pen needle. Always use a new pen needle for each injection, which the Instructions for Use explains is to help prevent infections and blocked needles. Pull the paper tab off the outer needle shield, push the capped needle straight onto the pen, and twist it on until it is tight.
Remove both needle shields. Pull off the outer needle shield and keep it, because it is reused later to cap the needle safely. Pull off the inner needle shield and put it in your household bin.
The pen is now ready to prime.
Injecting Your Dose and Confirming You Received It
Choose and rotate the site. You or someone else can inject into the thigh or the stomach area, at least 5 centimetres from the belly button. For the back of the upper arm, another person should give the injection. Change the injection site each week; you may use the same area of your body, but choose a different site within it.
Dial the dose. Turn the dose knob until it stops and the end-of-dose icon shows in the dose window. That is one full 0.6 ml dose. The pen delivers a fixed dose, so there is no dose to calculate.
Inject. Insert the needle into your skin, then push the dose knob in until it stops and slowly count to five while holding it. The icon must show in the dose window before you remove the needle.
Check the dose went in. Pull the needle out of your skin. A drop of medicine on the needle tip is normal and does not affect your dose. Confirm the icon is in the dose window: if it is, you have had the full dose. If it is not, insert the needle back into your skin and finish the injection. Do not redial the dose. If you still do not think you received a full dose, do not start over and do not repeat the injection; speak to your doctor, pharmacist or nurse.
Do not use the markings on the cartridge as a dose indicator. The dose window is the only reliable readout.
After Your Injection: Needles, Storage and Disposal
If the site bleeds, press it lightly with gauze or a cotton ball. Do not rub it.
Cap and remove the needle. Carefully replace the outer needle shield you kept earlier, then unscrew the capped needle and put it straight into a sharps container. Do not store the pen with the needle attached. The Instructions for Use gives three reasons: it prevents leaking, a blocked needle, and air entering the pen. That last one connects directly back to priming, which exists to clear air from the cartridge.
Replace the pen cap. Do not store the pen without its cap attached.
Storing an unused pen. Keep it in the refrigerator between 2°C and 8°C, where it may be used until the expiry date printed on the label. Do not freeze it, and discard the pen if it has been frozen.
Storing a pen you have started. After your injection you may keep the pen at room temperature up to 30°C, away from heat, and out of the sight and reach of children.
When to throw the pen away. Two limits apply and whichever comes first ends the pen's life: dispose of it 30 days after first use, and dispose of it after the fourth weekly dose. Put used needles in a sharps container immediately after use rather than loose in household waste, dispose of the pen as your healthcare professional instructs, and do not recycle a used sharps container.
Safety Checks and When Not to Use Your Pen
Each pen holds four fixed doses, one taken weekly, so a KwikPen covers four weeks at a single strength. Do not throw a pen away after one injection, and do not try to use any medicine left in it after the fourth dose.
Do not share your pen with anyone, even if the needle has been changed. The Instructions for Use is explicit about why: you may pass on or acquire a serious infection.
If you are blind or have vision problems, do not use the pen without help from someone trained to use it.
Before each injection, confirm: the name and strength on the label match your prescription, which matters most just after a dose increase when two strengths may be in the house; the expiry date has not passed; the pen is undamaged and has not been frozen; and the medicine is colourless to slightly yellow, not cloudy, discoloured or full of particles.
If the pen cap will not come off, gently twist it back and forth and then pull. If the dose knob is hard to push, pushing more slowly makes it easier; the needle may also be blocked, in which case fit a new needle and prime the pen again. If you suspect dust, food or liquid has got inside the pen, do not use it.
Reporting a problem. If you get any side effects, talk to your doctor, pharmacist or nurse, and you can report suspected side effects directly via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk. Reporting helps provide more information on the safety of this medicine. If the pen itself appears faulty, tell the pharmacy that supplied it.
Mounjaro is a prescription-only medicine. It is one option a prescriber may consider following a consultation with Bolt Pharmacy, and is only prescribed where it is clinically appropriate.
Scientific References
- Mounjaro 2.5 mg KwikPen solution for injection in pre-filled pen. Summary of Product Characteristics.
- Yellow Card – Report a problem with a medicine or medical device. Medicines and Healthcare products Regulatory Agency..
- Tirzepatide, a dual GIP/GLP-1 receptor co-agonist for the treatment of type 2 diabetes with unmatched effectiveness regarding glycaemic control and body weight reduction. Cardiovascular Diabetology..
- Clinical Potential of GIP in Type 2 Diabetes and Obesity. Diabetes Care..
- Early worsening of diabetic retinopathy in individuals with type 2 diabetes treated with tirzepatide: a real-world cohort study. Diabetologia..
- Translating the research in insulin injection technique: implications for practice. The Diabetes Educator..
- Skin-related complications of insulin therapy: epidemiology and emerging management strategies. American Journal of Clinical Dermatology..
- A New Medical Device for Improved Rotation of Insulin Injections in Type 1 Diabetes Mellitus: A Proof-of-Concept Study. Journal of Diabetes Science and Technology..
- Mounjaro KwikPen. Instructions for Use (User Manual).
- Mounjaro KwikPen. Package leaflet: Information for the patient.
Frequently Asked Questions
Do I need to prime my Mounjaro KwikPen?
Yes. Priming is steps 7 to 9 of the UK Instructions for Use supplied with the pen, and it removes air from the cartridge while confirming the pen is working correctly. Turn the dose knob until you hear two clicks and the extended line shows in the dose window, tap the cartridge holder with the needle pointing up, then push the dose knob in and hold for five seconds, releasing the medicine into the air rather than into your body.
What if no medicine comes out when I prime my Mounjaro pen?
The Instructions for Use gives a bounded sequence. Repeat the priming steps no more than two further times. If you still see no medicine, fit a new pen needle and repeat once more. If there is still nothing, stop and contact your local Lilly affiliate, or speak to your doctor, pharmacist or nurse. Do not keep repeating beyond that.
How many doses are in a Mounjaro KwikPen?
Four fixed doses of 0.6 ml, one taken each week, all at the pen's single strength. Do not discard the pen after one injection. Dispose of it after the fourth weekly dose, or 30 days after first use, whichever comes first, and do not try to use any medicine remaining in it.
Do I have to attach a needle to a Mounjaro KwikPen?
Yes. The KwikPen uses a compatible pen needle that you attach yourself, and needles are not included in the pack, so ask your doctor, pharmacist or nurse which to use. Fit a new needle for every injection to help prevent infections and blocked needles, and unscrew it into a sharps container afterwards. Do not store the pen with the needle attached.
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