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Therapeutic Index Calculator

TI = TD₅₀ / ED₅₀ – safety margin

Enter Doses

Dose effective in 50% of population

Example Drugs

TI Safety Guidelines

TI RangeClassificationMonitoring
TI < 2Very NarrowContinuous TDM required
TI 2–5NarrowRegular TDM recommended
TI 5–10ModerateRoutine monitoring
TI > 10WideMinimal monitoring

Note

TI derived from quantal dose‑response curves in animals [citation:4][citation:9]. For humans, therapeutic window based on population data.