PSA Renal and Hepatic Prescribing 2

Question 1

A patient with severe hepatic impairment is prescribed warfarin. What change in anticoagulant response is expected compared to a patient with normal liver function?

Accepted Answer

INR will be higher than expected, requiring lower doses

Answer

Hepatic impairment both reduces clotting factor synthesis and impairs warfarin metabolism, leading to enhanced anticoagulant effect and elevated INR.

Question 2

Morphine should be used with extreme caution in renal failure primarily due to accumulation of which active metabolite?

Accepted Answer

Morphine-6-glucuronide (M6G)

Answer

Morphine-6-glucuronide (M6G) is a potent active analgesic metabolite that accumulates in renal failure and can cause profound respiratory depression.

Question 3

Which formula is the standard method recommended for estimating creatinine clearance when adjusting drug doses in renal impairment?

Accepted Answer

Cockcroft-Gault equation

Answer

The Cockcroft-Gault equation is the standard formula used for drug dosing calculations in renal impairment as it was validated using drug clearance data.

Question 4

A patient with CrCl 30 mL/min is prescribed digoxin. Compared to a patient with normal renal function, the expected pharmacokinetic change is:

Accepted Answer

Prolonged half-life, requiring dose reduction

Answer

Digoxin is 70% renally excreted; in renal impairment, its half-life is prolonged significantly, requiring maintenance dose reduction to prevent toxicity.

Question 5

Which analgesic should be avoided in renal impairment due to accumulation of its neurotoxic active metabolite, norpethidine?

Accepted Answer

Pethidine (meperidine)

Answer

Pethidine is metabolized to norpethidine, a neuroexcitatory metabolite that accumulates in renal failure and causes CNS toxicity including seizures.

(PSA) Prescribing Safety Assessment Practice Test

(PSA) Prescribing Safety Assessment Practice Test

PSA Renal and Hepatic Prescribing 2