Match each clinical pharmacokinetic scenario with its primary underlying mechanistic consequence.
- Adding rifampin to the regimen of a patient stabilized on apixabanIncreased drug clearance via induction of cytochrome P450 enzymes
- Prescribing probenecid to prolong the therapeutic effect of a penicillin antibioticDecreased renal excretion via competitive inhibition of organic anion transporters
- Initiating oral propranolol in a patient with Child-Pugh class C cirrhosisIncreased systemic bioavailability via reduced hepatic first-pass extraction
- Taking over-the-counter calcium carbonate simultaneously with oral ciprofloxacinDecreased gastrointestinal absorption via formation of insoluble drug complexes
- Administering a standard dose of gentamicin to a patient with anuric renal failureProlonged elimination half-life via severe reduction in glomerular filtration rate
Answer
Rifampin + apixaban results in increased clearance via CYP450 induction; Probenecid + penicillin results in decreased renal excretion via OAT inhibition; Cirrhosis + propranolol results in increased systemic bioavailability via reduced first-pass extraction; Calcium + ciprofloxacin results in decreased GI absorption via complex formation; Gentamicin + anuric renal failure results in prolonged half-life via reduced GFR.
Each clinical scenario corresponds to a specific alteration in ADME: Rifampin induces CYP enzymes (metabolism); Probenecid blocks tubular secretion (excretion); Cirrhosis impairs first-pass metabolism (absorption/metabolism); Calcium chelates quinolones (absorption); and ESRD halts glomerular filtration (excretion).
Step-by-Step Solution
Key Concept
Pharmacokinetic mechanisms altering drug absorption, distribution, metabolism, and excretion (ADME) in specific clinical scenarios.