This system is probably from the induction of hepatic microsomal enzymes that metabolize the antibiotic. If phenobarbital and doxycycline are administered concurrently, the medical reaction to doxycycline needs to be monitored carefully. Phenytoin, sodium valproate, valproic acid: The effect of barbiturates over the metabolism of phenytoin seems to get variable. https://mehery109lxi2.ktwiki.com/user