Which administration route involves the injection of medication into the fatty tissue?

The administration route that involves injecting medication into the fatty tissue is subcutaneous. This method is typically utilized for delivering medications that are absorbed slowly and steadily into the bloodstream. The fatty tissue is found just beneath the skin, making it ideal for this type of administration.

Medications administered subcutaneously can include insulin and certain vaccinations. The injection is made at a 45 to 90-degree angle, depending on the amount of subcutaneous tissue present on the patient. This technique allows for sustained release of the medication over time, which is particularly beneficial for managing chronic conditions.

In contrast, the intramuscular route involves injecting medication directly into a muscle, which allows for faster absorption due to the rich blood supply in muscles. The intravenous route delivers medications directly into the bloodstream through a vein, providing immediate effects, while the topical route is applied to the skin's surface and does not involve injections at all. Each of these routes serves different purposes based on the desired speed and method of medication absorption.