Which route of administration involves injecting medication into muscle tissue?

Injecting medication into muscle tissue is known as intramuscular administration. This method allows for a more rapid absorption of the medication compared to other routes, due to the rich blood supply in muscle tissue. Medications delivered intramuscularly can be used for a variety of purposes, such as vaccines, hormones, and antibiotics, and are particularly useful when a larger volume of medication is needed compared to subcutaneous injections.

Contrasting this with other routes, intradermal injections are given into the skin, primarily used for allergy tests and tuberculosis screening, which limits their volume and absorption rate. Subcutaneous administration involves injecting medication into the fatty tissue just beneath the skin, suitable for smaller volumes and slower absorption, such as insulin or heparin. Topical administration, on the other hand, involves delivering medication directly onto the skin or mucous membranes for localized effect, which is not appropriate for systemic delivery or larger volumes.

Thus, intramuscular administration is the most effective route for those medications needed to be absorbed quickly and in larger doses.