Adjusting drugs when the kidney or liver cannot clear them normally.
Key points
• Some renally cleared drugs, such as gentamicin and digoxin, need dose adjustment or avoidance in renal impairment, and certain opioids and their metabolites also accumulate; metformin should be avoided when the eGFR is below 30 mL/min/1.73m2.
• Estimate renal function (eGFR or creatinine clearance) and dose accordingly.
• In liver failure avoid hepatotoxins and drugs needing hepatic activation; sedatives can precipitate encephalopathy.
• Monitor levels for narrow-therapeutic-index agents.
Memory trick
Failing kidney or liver -> reduce the dose of what it clears.