In patients with severe renal impairment, which opioid can be a reasonable option, while it should be avoided in severe hepatic impairment?

In patients with severe renal impairment, which opioid can be a reasonable option, while it should be avoided in severe hepatic impairment?

• A. Morphine
• B. Methadone
• C. Fentanyl
• D. Hydrocodone

Answer: (B)

The concept tested is how opioid pharmacokinetics change with organ impairment and how that guides safer choices. In severe renal impairment you want to avoid opioids that rely on kidney clearance or have active metabolites that accumulate. Methadone fits this well because it is cleared mainly by hepatic metabolism with minimal renal excretion and what is excreted does not include active opioids. This means kidney failure is less likely to cause accumulation or heightened toxicity with methadone. In contrast, morphine and hydrocodone produce active metabolites that are cleared by the kidneys and can build up in severe renal impairment, increasing the risk of sedation and respiratory depression. Fentanyl is largely hepatically metabolized and lacks troublesome active renal metabolites, but severe hepatic impairment reduces its clearance, so dosing becomes more risky and it’s not as predictable in that setting. Therefore, methadone is a reasonable option in severe renal impairment, while it should be avoided in severe hepatic impairment due to reduced hepatic clearance and higher overdose risk.

The concept tested is how opioid pharmacokinetics change with organ impairment and how that guides safer choices. In severe renal impairment you want to avoid opioids that rely on kidney clearance or have active metabolites that accumulate. Methadone fits this well because it is cleared mainly by hepatic metabolism with minimal renal excretion and what is excreted does not include active opioids. This means kidney failure is less likely to cause accumulation or heightened toxicity with methadone. In contrast, morphine and hydrocodone produce active metabolites that are cleared by the kidneys and can build up in severe renal impairment, increasing the risk of sedation and respiratory depression. Fentanyl is largely hepatically metabolized and lacks troublesome active renal metabolites, but severe hepatic impairment reduces its clearance, so dosing becomes more risky and it’s not as predictable in that setting. Therefore, methadone is a reasonable option in severe renal impairment, while it should be avoided in severe hepatic impairment due to reduced hepatic clearance and higher overdose risk.