What angle should the needle be inserted when administering heparin subcutaneously?

When administering heparin subcutaneously, the needle should be inserted at a 90° angle. This angle is appropriate because it allows for the delivery of the medication directly into the subcutaneous tissue where it can be absorbed effectively. Heparin is typically given in areas such as the abdomen or the thigh, which have a sufficient amount of subcutaneous tissue to accommodate the injection.

The choice of a 90° angle ensures that the needle penetrates through the skin and into the fatty tissue without introducing the medication into the muscle tissue, which could lead to faster absorption and potentially alter the drug's effects. Additionally, this angle minimizes discomfort for the patient while optimizing the delivery of the medication.

Using different angles, such as 45°, 30°, or 60°, may not provide the necessary depth of injection into the subcutaneous layer and could increase the risk of complications or inadequate drug delivery.