MTM Renal Dosing & Adjustments 3 — Questions and Answers
Question 1: A patient with stage 4 CKD (CrCl 20 mL/min) is started on enoxaparin for DVT treatment. What is the recommended dosing adjustment?
- No adjustment needed
- Reduce dose by 25%
- Reduce dose to 1 mg/kg once daily (Correct answer)
- Switch to unfractionated heparin only
Correct answer: Reduce dose to 1 mg/kg once daily
For CrCl < 30 mL/min, enoxaparin DVT treatment dose is reduced to 1 mg/kg subcutaneously once daily.
Question 2: Which of the following describes the 'drug interval extension' strategy for renal dosing adjustments?
- Giving a smaller dose at the same frequency
- Giving the same dose at longer intervals (Correct answer)
- Giving both a smaller dose and longer intervals
- Loading with a normal dose then reducing maintenance
Correct answer: Giving the same dose at longer intervals
Interval extension maintains the same dose size but increases the time between doses to compensate for slower elimination.
Question 3: A patient on peritoneal dialysis requires antibiotic therapy for peritonitis. Which route of administration is preferred?
- Intravenous
- Oral
- Intraperitoneal (Correct answer)
- Intramuscular
Correct answer: Intraperitoneal
Intraperitoneal antibiotic administration delivers drug directly to the site of infection in peritoneal dialysis patients.
Question 4: Dabigatran is contraindicated in patients with CrCl below what threshold due to risk of bleeding?
- 60 mL/min
- 45 mL/min
- 30 mL/min (Correct answer)
- 15 mL/min
Correct answer: 30 mL/min
Dabigatran is contraindicated when CrCl < 30 mL/min because 80% is renally eliminated, leading to dangerous drug accumulation.
Question 5: Which pharmacokinetic parameter determines how much drug is removed by hemodialysis?
- Volume of distribution
- Protein binding
- Both volume of distribution and protein binding (Correct answer)
- Half-life only
Correct answer: Both volume of distribution and protein binding
Drugs with low protein binding and small volume of distribution are most readily removed by hemodialysis.
Question 6: A patient with CrCl of 35 mL/min needs antifungal therapy. Which agent requires dose adjustment?
- Fluconazole (Correct answer)
- Micafungin
- Anidulafungin
- Caspofungin
Correct answer: Fluconazole
Fluconazole is primarily renally excreted and requires 50% dose reduction when CrCl falls below 50 mL/min.
Question 7: Which statement about metformin and renal function is CORRECT per current guidelines?
- Metformin is contraindicated when eGFR < 60 mL/min/1.73m²
- Metformin can be continued with dose reduction when eGFR is 30–45 mL/min/1.73m² (Correct answer)
- Metformin has no renal contraindications
- Metformin must be stopped if eGFR < 60 mL/min/1.73m²
Correct answer: Metformin can be continued with dose reduction when eGFR is 30–45 mL/min/1.73m²
Current guidelines allow metformin use at reduced doses when eGFR is 30–45, but it should be discontinued below 30 mL/min/1.73m².
MTM Renal Dosing & Adjustments 3
A patient with stage 4 CKD (CrCl 20 mL/min) is started on enoxaparin for DVT treatment.
What is the recommended dosing adjustment?