Effect of phenobarbital on the disposition of intravenous theophylline

Abstract

The disposition of intravenous doses of theophylline was determined in normal male subjects before and after treatment with phenobarbital 2 wk. Although there was some variation in disposition of the 2 drugs, there were no significant effects of phenobarbital on theophylline kinetics. We conclude that theophylline dosage need not be altered during concomitant administration of phenobarbital.

Theophylline‐rifampicin interaction: non‐selective induction of theophylline metabolic pathways.

“…The magnitude of the induction of rifampicin is similar to that observed in cigarette smokers (Grygiel & Birkett, 1981) but substantially greater than that due to sulphinpyrazone (Birkett et al, 1983b) and phenobarbitone (Piafsky et al, 1977). Average theophylline maintenance dose may need to be increased about 1.5 to 2-fold in patients who are taking rifampicin to achieve optimal therapeutic plasma concentrations and reduced if rifampicin is stopped during theophylline treatment.…”

Factors affecting theophylline clearances: Age, tobacco, marijuana, cirrhosis, congestive heart failure, obesity, oral contraceptives, benzodiazepines, barbiturates, and ethanol

“…(37) who found a mean increase in theophylline cbj-of 34% in six healthy subjects following 4 weeks of phenobarbital administration. In contrast, Piafsky et al (71) found no such effect after briefer phenobarbital treatment in healthy adults. Microsomal enzymes for theophylline metabolism in the rat also are weakly susceptible to barbiturate induction, but, as in humans, are more strongly affected by polycyclic aromatic hydrocarbons (30).…”

Maturation of caffeine elimination in infancy.

“…The possibility that the elimination of caffeine in this infant could have been induced by these drugs exists, but available data suggest that phenobarbitone and phenytoin have little effect on methylxanthine disposition (Greene et al, 1977;Piafsky et al, 1977;Ogilvie, 1978).…”