The modern pen needles are very thin, finely polished and covered with a sliding film. After each use, the needle becomes dull or gets small deformations and loses its lubricity by wear of the sliding film. The deformed needle tip can therefore additionally cause the smallest injuries in the fatty tissue and hardening. In addition, sterility is no longer guaranteed after use. Examinations show that multiple use of the pen needle creates various health risks for patients.
What happens if a pen needle is used multiple times?
- The wear on the needle tip can cause minor injuries and bleeding (bruises) in addition to the actual puncture. Not only will the injections become increasingly painful, it will also increase the risk of lipohypertrophy. This change in subcutaneous fatty tissue (adipose tissue growth) changes the absorption (uptake) of insulin at these sites. The result is an incalculable onset of insulin and thus the risk of blood sugar fluctuations.
- The pen needle is no longer sterile after the first use. In addition, tissue remnants may adhere to the pen needle. Not only is this unhygienic, it also increases the risk of infection.
- Crystallized insulin and adhering tissue residues can lead to blockage of the pen needle and thus to an underdose of insulin.
- Air bubbles in the insulin cartridge may continue to expand or re-form with the needle attached, depending on the temperature. As a result, insulin drops out of the needle after injection and there is a risk of inaccurate dosing by air injection.