Parenteral administration refers to which practice?

• A. Oral administration
• B. Intravenous administration bypassing the GI system
• C. Rectal administration
• D. Inhalation

Answer: (B)

Parenteral administration means delivering a drug by routes that bypass the gastrointestinal tract. Injecting a drug directly into the bloodstream, as with intravenous administration, is the clearest example: it goes straight into circulation, giving immediate, complete systemic availability and avoiding absorption from the gut and any first-pass metabolism by the liver. In contrast, oral and rectal routes involve the digestive system, with absorption that can be slower and more variable and, for oral administration, full first-pass metabolism. Inhalation also avoids the GI tract, but the classic illustration of parenteral delivery is intravenous administration, which best exemplifies the concept.