Phenobarbital pharmacokinetics and bioavailability in adults

J Clin Pharmacol. 1982 Feb-Mar;22(2-3):141-8. doi: 10.1002/j.1552-4604.1982.tb02662.x.


The pharmacokinetics and bioavailability of phenobarbital were examined in six healthy adult subjects after a 2.6 mg/kg intravenous and a 2.9 mg/kg oral dose. Serum concentrations of phenobarbital were followed by means of a high pressure liquid chromatographic assay for 21 days after drug administration. After the intravenous dose, the mean distribution half-life was 0.18 hour and the mean elimination half-life was 5.8 days. Mean total body clearance and mean renal clearance were 3.0 ml/hr/kg and 0.8 ml/hr/kg, respectively. The apparent volume of distribution was 0.60 liter/kg. After administration of phenobarbital tablets, the maximum phenobarbital serum concentration was 5.5 mg/liter at 2.3 hours after the dose. Adjusted absolute availability of phenobarbital from the tablets studied was 94.9 per cent (range 81-111.9 per cent). The elimination half-life averaged 5.1 days for the oral dose. There was no evidence of autoinduction of phenobarbital elimination over the study period.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Biological Availability
  • Half-Life
  • Humans
  • Kinetics
  • Male
  • Phenobarbital / metabolism*
  • Time Factors


  • Phenobarbital