Antivirals Renal Dosing by Creatinine Clearance

This hub covers renal dose adjustment for antivirals (8 agents) by creatinine clearance. Each drug links to its own page with the full threshold, cautions, and an FDA-label reference. Many drugs in this class are cleared by the kidneys, so their dose or interval changes as filtration falls — accumulation of the parent drug or active metabolites is what drives the risk.

Reviewed by Dr. Rishi Kumar Kafle, MBBS, MD, FASN — always confirm against the label

Antivirals: Renal Dosing at a Glance

How to Use This Table

The four standard creatinine-clearance bands — above 50, 30–50, 15–30, and below 15 mL/min — are a starting framework, but each drug's own cutoff overrides them. Estimate the patient's clearance, find the agent below, then confirm the exact dose against its current label.

What Each Drug Page Covers

Every antivirals page below follows the same structure: an answer-first summary of the renal rule, a table of the threshold and key caution, the pharmacokinetic reason the drug accumulates as filtration falls, guidance for severe impairment and dialysis, a worked example of how to calculate the patient's clearance, monitoring and re-estimation triggers, and special-population notes for older adults, obesity, and acute kidney injury. Each page also links the drug's FDA label through DailyMed so you can confirm the exact numbers at the source, and every clinical value remains reviewer-pending until a clinician signs off.

How Reduced Kidney Function Affects This Class

Renal impairment changes drug handling in two ways that matter for antivirals: it slows elimination of drugs and active metabolites cleared by the kidney, and it shifts the balance of benefit and harm — bleeding, sedation, electrolyte disturbance, or toxicity become more likely at the same nominal dose. For agents in this class with a narrow therapeutic window, even a modest fall in clearance can move a standard dose into the toxic range, which is why the thresholds above are followed closely rather than treated as approximate. Where an agent is dosed by eGFR instead of creatinine clearance, the label reflects the trials that supported it; for most drugs, dosing studies were validated against Cockcroft–Gault creatinine clearance.

Choosing within the class also matters: when one agent must be avoided below a clearance threshold, another in the same class may be safer, and the per-drug pages note these trade-offs. Always weigh the indication, the patient's trajectory, and monitoring availability — an estimate is a starting point, not a substitute for clinical judgement.

Whichever agent you choose, document the renal estimate the dose was based on, the equation and weight used, and the date — because kidney function moves. A dose that was correct at a creatinine clearance of 60 mL/min may be wrong a week later if the patient becomes dehydrated, starts a second nephrotoxic drug, or develops an acute illness. Re-estimating at those moments, and again once a changing creatinine has settled to a steady state, is the single most reliable way to keep antivirals both effective and safe in reduced kidney function. For the underlying method, see the Cockcroft–Gault equation and how creatinine clearance differs from eGFR.

Calculate the Patient's CrCl First

Apply the right threshold by estimating creatinine clearance with the Cockcroft–Gault equation, using the appropriate dosing weight — ideal for normal-to-lean patients, adjusted in obesity, actual when below ideal. Re-estimate whenever kidney function may have changed, since acute illness and dehydration can lower clearance within days.