Can diabetic insulin needles be reused?

Once is never

Dr. Hans-Peter Weinschenck, King. Priv. Pharmacy Satrup / Mittelangeln

To be thrifty is a virtue - of course, nowadays too. And because that is the case, many diabetics save on having to change the insulin cannula regularly. I often hear: "I only change the cannula when the puncture hurts." Many diabetics even use the same cannula for months! That is certainly well-intentioned, but it does exactly the opposite and is harmful for the person concerned. In a Europe-wide study, the consequences of reusing insulin needles were examined on 1000 diabetics. While Italians and French use the needle an average of 1.5 times, we thrifty Germans use the needle an impressive 4.5 times; - Many users even use the needle until the insulin cartridge is empty! The other findings also make you sit up and take notice:

What happens if the insulin needle is reused?

  • The needle is no longer sterile. The risk of infection is low, however, because the preservative in the insulin disinfects the cannula
  • The tip becomes blunt and can bend. In the worst case, it can even break off and get stuck in the patient's skin or subcutaneous fatty tissue. (A person affected told me of such a mishap; the fragment was not found again despite an intensive search in the hospital. Since then, the area in question has been painful when lying down.
  • The silicone lubricant film is completely rubbed off when it is reused. Due to the lack of a sliding layer and the deformed needle tip, the injections become increasingly painful.
  • Bleeding and bruising may occur at the injection site.

What are the medical risks?

  • When reusing a needle, the tip bends (see above).
  • Injection with such a deformed needle damages the tissue and causes the smallest injuries.
  • These injuries promote the release of growth factors that, in conjunction with insulin, lead to the formation of fat growths. People who change the needle less often are much more likely to suffer from this so-called lipodystrophy.
  • If you inject into these fat growths (which is convenient because it is very painless), the insulin is not reliably and traceably released from the tissue to the blood, and the insulin effect cannot be predicted. The blood sugar control worsens.

And what do air bubbles in the cartridge have to do with reusing pen needles?

  • If you leave the needle on the pen between injections, air can enter the pen cartridge if the temperature fluctuates.
  • If you inject insulin from a cartridge like this, your pen will drip while the insulin is delivered and it will take longer than normal to inject the full dose.
  • If you stop using the pen too soon after the injection (even if it has been in the tissue for 10 seconds), there is a risk that you will inject an incomplete dose. The result: blood sugar fluctuations can occur, the cause of which is not recognized.

So it would be wise to always change the cannula after each injection. (This is also the recommendation of the Robert Koch Institute, the central institution of the federal government in the field of disease monitoring and prevention). In addition, the injection area must be varied regularly and systematically according to the plan (!). Ask your doctor or pharmacist about an injection schedule. Those who cannot get used to single use should at least renew the cannula daily (remove the cannula from the pen overnight!). With this procedure, however, the liability of the cannula manufacturer expires, so I cannot agree with this recommendation here. Incidentally, the needle of the lancing device should also be changed frequently and regularly, as this results in significant scarring on the fingers. Whoever saves sometimes pays twice.

Dr. Hans Peter Weinschenck