A comparison of the absorption of phenobarbitone given via the oral and the intramuscular route.

6 patients were given 180mg phenobarbitone, and 1 patient 120mg, and the plasma levels measured within the first 4 hours or so. These doses of phenobarbitone were quite ineffective in achieving, in a reasonable time, the levels generally recognised as being protective against seizures. 5 patients were loaded with phenobarbitone alternately via the oral and intramuscular routes to assess the relative absorption of phenobarbitone by each route. The oral route of administration appeared to be at least as good as the intramuscular, there being no significant difference between the two as judged by the peak levels of plasma phenobarbitone measured, or the amount of drug absorbed.