Pharmacy Practice (Patient Care): Assessment, Drug Therapy Problems and Monitoring
The patient-care sequence
Patient-care questions test a sequence, not a single fact: gather subjective and objective data, identify drug therapy problems, set goals, select and individualize a regimen, monitor, and document. The drug therapy problem categories are the backbone - unnecessary drug, needs additional therapy, ineffective drug, dose too low, adverse drug reaction, dose too high, and nonadherence. Before choosing an intervention, decide whether the problem lies in indication, effectiveness, safety or adherence.
Individualizing and monitoring
Adjust for renal and hepatic function (Cockcroft–Gault for creatinine clearance, Child–Pugh for hepatic impairment), plus age, weight, pregnancy and interactions. Monitoring means pairing each drug with a specific parameter: warfarin with INR; ACE inhibitor or ARB with potassium and creatinine; metformin with renal function and vitamin B12; aminoglycosides with serum levels and creatinine; opioids with sedation and respiratory rate.
Traps
A "best next step" question usually rewards the safest, least invasive action - assess, stop the offending agent, counsel - over immediately prescribing something new. Distinguish an adverse drug reaction from a true allergy, a side effect from toxicity, and failure of efficacy from a dosing error. Read whether the question asks what you do first versus what is most appropriate overall.
Worked example
A 78-year-old woman weighing 60 kg with serum creatinine 1.2 mg/dL needs a renally cleared antibiotic. Cockcroft–Gault: CrCl = [(140 − 78) × 60] / (72 × 1.2) × 0.85 ≈ 43.7 mL/min, which is moderate impairment. The maintenance dose is reduced or the interval extended, but the loading dose is left unchanged - reducing the loading dose is the classic trap.