Which term describes the rate of absorption into the bloodstream, the completeness of absorption, the speed of the drug's action, and the duration of the drug's action?

Which term describes the rate of absorption into the bloodstream, the completeness of absorption, the speed of the drug's action, and the duration of the drug's action?

• A. Bioavailability
• B. Routes of drug administration
• C. Pharmacodynamics
• D. Therapeutic index

Answer: (B)

Bioavailability describes how much of the drug reaches the bloodstream and how quickly it does so, which directly influences both how fast the drug starts working and how long its effects last. The rate of absorption and the extent of absorption are core parts of bioavailability, so higher or faster absorption means quicker onset and a more predictable duration of action. The other terms describe different ideas: routes of administration is about how the drug is given (oral, IV, etc.), pharmacodynamics is about the drug’s effects on the body, and the therapeutic index relates to safety margins.

Bioavailability describes how much of the drug reaches the bloodstream and how quickly it does so, which directly influences both how fast the drug starts working and how long its effects last. The rate of absorption and the extent of absorption are core parts of bioavailability, so higher or faster absorption means quicker onset and a more predictable duration of action. The other terms describe different ideas: routes of administration is about how the drug is given (oral, IV, etc.), pharmacodynamics is about the drug’s effects on the body, and the therapeutic index relates to safety margins.