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Medicines phenytoinQuestion & answer

phenytoin · Medicine question

What is the average plasma half-life of phenytoin in humans?

iatroX medicinesPublished 8 November 2026

The answer

Answer

The plasma half-life of phenytoin in humans averages 22 hours, with a range of 7 to 42 hours.

Sources for this answer

Epanutin 30mg/5ml oral SuspensionViatris (formerly Mylan or Upjohn) · emc · SmPC §5.2 Pharmacokinetic properties · Version 28Document updated 2 February 2026

Sources checked 8 November 2026

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phenytoin

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