Risks of multiple use Reuse of a pen needle can lead to the following risks:

The pen needle is somewhat blunted after single use, the lubricant film can show signs of wear and the tip of the pen needle can be deformed:
- Injections become more painful.
- This can lead to small injuries or bruising.
The pen needle is no longer sterile after initial use:
- Re-use is not hygienic.
- Increased risk of infections.
Insulin can crystallise in the pen needle:
- The pen needle may become clogged and a safe insulin injection is therefore no longer guaranteed.
- This can lead to dosage errors and unexpectedly high blood glucose levels.
Presence or increase in size of air bubbles in the cartridge:
- Insulin may drip out of pen needle (during storage).
- Insulin dose becomes inaccurate.