A prospective study of the hazards of multiple use of disposable syringes and needles in intensified insulin therapy.

The aim of the present study was to evaluate the potential hazards of multiple use of disposable syringes and needles for insulin injections over a long period of time. A special syringe container (pen-case) was developed to carry the syringe with insulin. In the microbial trial 24 patients, each injecting insulin for 1 week with one disposable needle, were studied for 201 patient-weeks with 5829 injections. Cultures of 154 needles, 155 syringe rinses, 154 pen-case rinses and the remains of insulin in 201 vials revealed no relevant contamination. In the clinical trial 100 diabetic patients were followed up for up to 7 years. Each syringe was reused for 1 to 12 weeks and each needle for 1 to 40 days (4 to 200 injections). Only sporadic redness not exceeding 4 mm2 was seen at sites of about 560,000 insulin injections. Thus, the repeated use of syringes and needles in one diabetic patient may be recommended as a convenient and safe approach in insulin administration.