Pitfalls in patient self-management of subcutaneous drug application : removal of rubber protection caps from ready-to-use syringes

Outpatient subcutaneous therapies are becoming more and more common, such as the use of low-molecular-weight heparins (LMWH) for prophylaxis or for the therapeutic treatment of thromboembolisms, multiple sclerosis, arthritis, anemia, or female infertility. Based on reports from patients and nurses indicating that some ready-to-use syringes require a concerted effort to remove the rubber protection cap, we decided to evaluate cap removal forces of commercial LMWH pre-loaded syringes as we were unable to find an ISO-norm from such syringes nor studies on this topic. In conclusion, the mechanical cap-pull-off tests confirmed the results from self- and observer’s assessments, and importantdifferences between brands were observed. The pulloff forces correspond roughly to the force needed to hold a narrow-neck plastic flask containing 1–3 l of water by pinching the neck between a finger and thumb.Medical staff should be aware of these possibly crucial handling difficulties and their consequences for successful therapy and compliance.