Which term describes the rate at which a drug is absorbed from the site of administration?

• A. Absorption rate
• B. Clearance
• C. Bioavailability
• D. Onset time

Answer: (A)

The rate at which a drug is absorbed from the site of administration describes how quickly the drug enters the bloodstream after dosing. This is the absorption rate, reflecting speed rather than amount. It isn’t about how much drug ultimately reaches circulation (that’s bioavailability); it isn’t about how the body clears the drug (that’s clearance); and it isn’t about when the drug’s effects begin (that’s onset time). In practice, a higher absorption rate speeds up reaching peak concentration (Tmax) and can shorten the time to onset of action, independent of the total amount absorbed.