How is pharmacokinetics defined?

• A. The inherited difference in the way a medication is metabolized and/or the effects of a medication on an individual
• B. The movement of a drug in the body (absorption, distribution, metabolism, excretion)
• C. The use of more than one drug in combination to achieve best results
• D. The ability of the drug to target specific muscles after administration

Answer: (B)

Pharmacokinetics focuses on how the body handles a drug, describing the four main processes: absorption into the bloodstream, distribution to tissues, metabolism to metabolites, and eventual excretion from the body. These steps determine how quickly a drug enters circulation, how widely it spreads, how it is cleared, and how long its effects last. The other descriptions fit different concepts: inherited differences in metabolism point to pharmacogenetics, using more than one drug describes polypharmacy, and targeting specific muscles relates to where a drug acts (pharmacodynamics or drug targeting) rather than how the body processes it.