Pharmacy & Medication Management Flashcards

A patient on warfarin therapy presents with an INR of 5.8 but shows no signs of active bleeding. According to DHA medication management guidelines, which intervention is most appropriate?

Answer: Hold warfarin and administer 1–2.5 mg oral vitamin K, recheck INR in 24 hours

For a supratherapeutic INR of 5.8 without active bleeding, guidelines recommend holding warfarin and giving a low oral dose of vitamin K (1–2.5 mg) to gently lower the INR without causing over-reversal, which could re-introduce thrombotic risk. High-dose IV vitamin K (10 mg) is reserved for serious/life-threatening bleeding. FFP is also reserved for active bleeding requiring immediate reversal. Continuing warfarin would be dangerous at this supratherapeutic level.

A pharmacist reviews an order for gentamicin 240 mg IV q8h for a 60 kg patient with a creatinine clearance of 35 mL/min. What is the most clinically appropriate action?

Answer: Maintain the dose but extend the interval to q24h or q36h

Aminoglycosides like gentamicin are renally cleared and nephrotoxic/ototoxic at elevated trough levels. In renal impairment (CrCl 35 mL/min), the preferred strategy is to maintain a standard single dose but extend the dosing interval to allow adequate drug elimination and prevent toxic accumulation — this preserves peak-dependent bactericidal activity. Dose reduction while keeping the standard interval risks subtherapeutic peaks. Tobramycin also requires renal adjustment and is not a safer alternative.

A 68-year-old patient taking sertraline 100 mg/day is prescribed tramadol 50 mg q6h for post-operative pain. Which serious adverse outcome is the primary concern with this combination?

Answer: Serotonin syndrome due to additive serotonergic activity

Tramadol inhibits serotonin and norepinephrine reuptake in addition to its opioid activity. Combined with an SSRI like sertraline, there is a clinically significant risk of serotonin syndrome (hyperthermia, clonus, agitation, autonomic instability). While tramadol's metabolism is affected by CYP2D6 (option D is partly true), and QT prolongation can occur, serotonin syndrome is the primary and most dangerous concern flagged in drug interaction databases for this specific combination.

During a medication reconciliation review, a clinical pharmacist discovers a patient's home medication list includes both amlodipine 10 mg and simvastatin 80 mg daily. What is the most appropriate recommendation?

Answer: Reduce simvastatin to 20 mg/day maximum due to amlodipine's CYP3A4 inhibition increasing statin exposure

Amlodipine is a weak CYP3A4 inhibitor and increases simvastatin plasma levels. Regulatory agencies (including FDA) recommend a simvastatin dose cap of 20 mg/day when used with amlodipine due to increased risk of myopathy and rhabdomyolysis at higher doses. Switching amlodipine or replacing simvastatin entirely may not be necessary — dose adjustment is the preferred, least disruptive intervention. Rosuvastatin is not metabolized by CYP3A4, so switching is an option but is more disruptive than a dose cap.

A pharmacist is counseling a nurse on administering vancomycin. The prescribed regimen is 1500 mg IV over 60 minutes. Which administration-related adverse effect requires the infusion rate to be slowed, and what is the underlying mechanism?

Answer: Red man syndrome caused by non-IgE-mediated mast cell degranulation and histamine release

Red man syndrome is the classic rate-dependent infusion reaction to vancomycin, characterized by flushing, erythema, and pruritus over the face, neck, and upper torso. It is NOT an allergic/IgE-mediated reaction but rather direct, non-immune mast cell degranulation triggered by rapid infusion rates, leading to histamine release. The treatment is to slow or stop the infusion and administer antihistamines. Nephrotoxicity is a separate, dose-dependent concern unrelated to infusion rate. Phlebitis is a local vascular issue, not the classic systemic reaction.

A patient with type 2 diabetes and an eGFR of 28 mL/min/1.73m² is currently on metformin 1000 mg BID, linagliptin 5 mg daily, and empagliflozin 10 mg daily. Which medication adjustment is most urgently required?

Answer: Discontinue metformin — it is contraindicated below eGFR 30 and should be stopped

Metformin is contraindicated when eGFR falls below 30 mL/min/1.73m² due to risk of lactic acidosis from drug accumulation. At eGFR 28, metformin must be discontinued immediately. Linagliptin is unique among DPP-4 inhibitors in requiring NO renal dose adjustment (it is excreted hepatically), making it suitable here. Empagliflozin's glycemic efficacy diminishes below eGFR 45, but its cardiovascular/renoprotective benefits now extend to lower eGFR thresholds per updated guidelines — but glycemic benefit stops, so continuation for glucose control alone would be reassessed. The most urgent and clear-cut action is stopping metformin.