sci.first-order-drug-clearance Calculator
Calculates first-order drug clearance: C(t) = C₀ × exp(−CL/Vd × t), elimination half-life t½ = 0.693 × Vd/CL, and dosing interval for target trough concentration. Aspirin t½ = 0.25 h (fast clearance); amiodarone t½ = 40–55 days (very slow) — loading doses are needed for drugs with long t½.
Inputs
- Cl L Hr
- Reference formula or conversion factor shown for context.
- Vd L
- Three-dimensional space occupied (m³ or L). 1 m³ = 1,000 L.
- Dose Mg
- Amount of medication administered per period. Most dosing is weight-based — verify with a licensed prescriber before clinical use.
- T Hr
- Amount of medication administered per period. Most dosing is weight-based — verify with a licensed prescriber before clinical use.
Results
- elimination half-life t₁/₂ (hr)
- Time for half the radioactive material to decay. After 10 half-lives, less than 0.1% of the original material remains.
- plasma conc at time t (mg/L)
- The computed duration or time value.
- initial concentration C₀ (mg/L)
- The proportional relationship between two quantities.
- AUC₀→∞ (mg·hr/L)
- Reference formula or conversion factor shown for context.
- ke = CL / Vd
- Reference formula or conversion factor shown for context.
- time to steady state (5×t₁/₂)
- The computed duration or time value.
order first elimination half drug