What is the primary route of administration for intermediate-acting insulin?

The primary route of administration for intermediate-acting insulin is subcutaneous. This route is ideal for insulin because it allows for a slower and more controlled absorption into the bloodstream, which is essential for managing blood glucose levels over an extended period. Intermediate-acting insulins, such as NPH (Neutral Protamine Hagedorn) insulin, are designed to provide a basal level of insulin that can last several hours, making subcutaneous administration highly effective for patients needing insulin therapy throughout the day.

Subcutaneous delivery involves injecting the insulin into the fatty tissue just beneath the skin, which helps to prevent rapid absorption that could lead to hypoglycemia. This method also avoids the complications associated with intravenous or intramuscular routes, such as the need for strict monitoring and potential variances in absorption rates. Oral administration is not appropriate for insulin, as it would be degraded in the digestive system, preventing it from entering systemic circulation effectively.