How to Inject Mounjaro: Using the KwikPen Step by Step

Mounjaro is injected once a week with a KwikPen. Each pen holds four fixed doses of one strength, and you prime the pen before every injection. This guide walks through each step as the UK instructions for use describe them, plus where to inject and what to do if something does not go to plan.

Before You Start

Check the pen and label, and have a new needle, swab and sharps container ready.

The Mounjaro KwikPen is a multi-dose, single-patient pen with 4 fixed doses, one a week, each of 0.6 ml. Pen needles are not included in the pack: ask your pharmacist which needle to use. You will also need a swab, gauze or cotton wool and a sharps container.

• Wash your hands with soap and water.

• Pull the pen cap straight off and check the label: the medicine name and dose must match your prescription.

• Do not use the pen if it is past its expiry date, looks damaged, has been frozen, or the medicine is cloudy, discoloured or has particles. It should be colourless to slightly yellow.

Read the instructions in the pack before your first injection and with each new pen.

Step 1: Attach a New Needle

Wipe the seal, attach a new needle and remove both needle shields.

• Wipe the red inner seal with a swab.

• Take a new pen needle, pull off its paper tab, push it straight onto the pen and twist until tight.

• Pull off the outer needle shield and keep it, then pull off the inner needle shield and throw it away.

Always use a new needle for each injection, to help prevent infection and blocked needles.

Step 2: Prime the Pen Before Every Injection

Before every injection: turn to the prime position, tap, push and look for a drop.

Priming removes air and checks the pen is working. With the KwikPen you do it before each injection:

• Slowly turn the dose knob until you hear 2 clicks and the extended line shows in the dose window. This is the prime position.

• Hold the pen with the needle pointing up and tap the cartridge holder gently to bring air bubbles to the top.

• Push the dose knob in until it stops and slowly count to 5. Do not inject this into your body.

A small amount of medicine should come out of the needle tip. If not, repeat the priming steps up to 2 more times; if there is still nothing, change the needle and try once more. If there is still no medicine, do not use the pen: contact your pharmacy, or Lilly, the manufacturer, as the instructions advise.

Step 3: Set Your Dose

Turn the dose knob until it stops at the full-dose symbol.

Turn the dose knob until it stops and the full-dose symbol shows in the dose window. That is one full 0.6 ml dose: the KwikPen gives a fixed dose, so there is nothing to measure. Do not use the marks on the pen body as dose indicators.

Step 4: Choose Where to Inject

Thigh or stomach, 5 cm from the belly button; back of upper arm only by another person.

• You or another person can inject into your thigh or stomach (abdomen), at least 5 cm from your belly button.

• The back of your upper arm should only be used if another person gives the injection.

Mounjaro is injected under the skin (subcutaneously). Change the injection site each week. You can use the same area of the body, but choose a different spot in that area. For more on injection sites, see where to inject Mounjaro.

Step 5: Inject Your Dose

Push the knob until it stops, count slowly to 5, then remove the needle.

• Insert the needle into your skin.

• Push the dose knob in until it stops, then slowly count to 5 while holding it.

• Pull the needle out. A drop of medicine on the needle tip is normal and does not affect your dose.

Check the dose window shows that the full dose has been given. If it does not, put the needle back into your skin and finish the injection. Do not redial the dose. If you still think you did not get the full dose, do not start over or repeat the injection; speak to your pharmacist or prescriber.

Step 6: After Your Injection

Recap and remove the needle into a sharps container; replace the pen cap.

• If there is a little blood, press lightly with gauze or cotton wool. Do not rub.

• Carefully replace the outer needle shield, unscrew the needle and put it in a sharps container.

• Do not store the pen with the needle attached, to prevent leaking, blocked needles and air getting in.

• Put the pen cap back on.

Never share your pen, even with a new needle, because of the risk of serious infection.

Storage, Missed Doses and the Fourth Dose

Fridge before first use, 30 days after; missed dose within 4 days; dispose after 4 doses.

• Storage: keep unused pens in the fridge. After first use, a pen can be kept at up to 30°C for up to 30 days. See how to store Mounjaro.

• Missed dose: take it within 4 days; after 4 days, skip it and take the next one on your usual day.

• After 4 doses: dispose of the pen. Do not try to inject any medicine left in it; see the Mounjaro "golden dose".

For the dose schedule, see Mounjaro dosage. Report suspected side effects to the MHRA Yellow Card scheme.

Frequently Asked Questions