Oral administration route phenobarbital

Cheever KL, DeBord DG, Swearengin TF. 1991.4,4 -Methylenebis(2-chloroaniline) (MOCA) The effect of multiple oral administration, route and phenobarbital induction on macromolecular adduct formation in the rat. Fundam AppI Toxicol 16(1) 71-80. 

The most common route of exposure to the long-acting barbiturates is ingestion of oral dosage forms. Phenobarbital is also available for parenteral administration. 

Unfortunately, only relatively few of the many papers published on povidone deal with its influence on bioavailability in vivo. However, where results are available, they almost always show an improvement in bioavailability. Figs. 49 to 51 show the effect of coprecipitation with povidone on the bioavailability of different active substances administered by different routes. Fig. 49 shows, as a typical example, the oral bioavailability of a nifedipine coprecipitate in the rat, Fig. 50 shows the rectal bioavailability of a phenobarbital coprecipitate in rabbits, while Fig. 51 shows the effect of a hydrocortisone coprecipitate on the human skin after percutaneous administration. In all three cases, the same dose of the pure active substance without povidone was applied for reference. 

Advantages. Phenobarbital has linear and predictable pharmacokinetics. If the dose is doubled, the resulting serum concentrations double. Multiple dosage forms (e.g., oral solid, oral liquid, intramuscular, and intravenous) are available, so the route of administration can be tailored to patient needs, including emergent conditions. It is the most inexpensive AED. 

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