Definition: A pen needle is a small, single-use needle that screws or clicks onto the tip of an injection pen. It has a short needle on the outside for your skin and a back end that pierces the pen cartridge. Multi-dose pens need a new one for each injection; some pens include them and some do not.
The Ozempic pen comes with NovoFine Plus 32G 4 mm needles, and its instructions say other compatible needles up to 8 mm long can be used. The Mounjaro KwikPen carton says needles are not included. The KwikPen instructions say to keep the outer needle shield, which is used again to remove the needle, and to throw the inner shield in the household trash.
The Lantus label says not to reuse needles. Reuse raises the risk of a blocked needle, which can mean a wrong dose, and of infection. The Ozempic label says a blocked needle may mean you received no medicine even though the dose counter moved, and to change the needle and start again.
The Ozempic instructions say to remove the needle carefully, not to put the needle caps back on, and to put the needle in a sharps disposal container right away. The Lantus instructions say not to put the inner needle cap back on, and describe guiding the needle into the outer cap to unscrew it. The steps differ by product, so follow the one for your pen.
Both labels say to store the pen without a needle attached.
Pen needles run out faster than pens: one per injection, plus any spare used after a blocked needle. Counting them as a supply alongside the pen helps you avoid reusing one. Needle length and gauge are worth noting in your log if you change brands.
Read more on Dose Track: Tracking vials and supplies · Ozempic guide