Which statement is true about bioavailability?

Which statement is true about bioavailability?

• A. The fraction of an administered dose that reaches systemic circulation
• B. Measures the potency of a drug
• C. Indicates how quickly a drug acts
• D. Describes the excretion rate of the drug

Answer: (A)

Bioavailability is the fraction of the administered dose that reaches systemic circulation. This is why the statement about how much of the dose actually gets into circulation is the correct description. The amount that appears in the bloodstream can be less than what was given due to incomplete absorption and first-pass metabolism, especially with oral routes. Potency means how strong the drug is at a given concentration, not how much dose reaches circulation. Onset of action depends on how quickly the drug is absorbed and distributed, not the total amount that enters the bloodstream. Excretion rate concerns how fast the drug is eliminated, not its entry into circulation. So the correct idea is the fraction of the dose that reaches systemic circulation.

Bioavailability is the fraction of the administered dose that reaches systemic circulation. This is why the statement about how much of the dose actually gets into circulation is the correct description. The amount that appears in the bloodstream can be less than what was given due to incomplete absorption and first-pass metabolism, especially with oral routes. Potency means how strong the drug is at a given concentration, not how much dose reaches circulation. Onset of action depends on how quickly the drug is absorbed and distributed, not the total amount that enters the bloodstream. Excretion rate concerns how fast the drug is eliminated, not its entry into circulation. So the correct idea is the fraction of the dose that reaches systemic circulation.