Which of the following is NOT a common parenteral route?

The correct response identifies "Topical" as not being a common parenteral route. Parenteral routes of administration include methods that involve delivering medications directly into the body, bypassing the gastrointestinal tract. This is typically done through injections, which can be intravenous, subcutaneous, or intramuscular.

Intravenous injections deliver medication directly into the bloodstream, providing immediate effects. Subcutaneous injections are administered into the fatty tissue beneath the skin, allowing for slower absorption. Intramuscular injections are given into a muscle, which allows for a larger volume of medication than subcutaneous injections, facilitating a quicker absorption into the bloodstream.

In contrast, the topical route involves applying medication directly onto the skin or mucous membranes. This method is designed for local effect rather than systemic absorption and is therefore not classified as a parenteral route. Understanding these distinctions is crucial for accurately administering medications and recognizing the differences in onset of action, absorption rates, and the types of medications that are most effective via each method.