How many half-lives until steady state is reached?

Approximately 4-5 half-lives to reach 94-97% of steady-state concentration. This applies to both accumulation to steady state after starting a drug and washout after stopping, assuming first-order kinetics.

How does renal failure affect elimination half-life?

For renally eliminated drugs, reduced GFR decreases CL, prolonging t½ proportionally: t½ ∝ Vd/CL. For a drug with 100% renal elimination, halving GFR approximately doubles the half-life.

First-Order Elimination Half-Life Calculator

Calculate the terminal elimination half-life (t½ = 0.693 / ke = 0.693 × Vd / CL) for first-order pharmacokinetic processes to determine time to steady state and drug washout after discontinuation.

Use the full interactive calculator below, or

First-Order Elimination Half-Life Calculator

Frequently Asked Questions

How many half-lives until steady state is reached?

How does renal failure affect elimination half-life?