4. Doxycycline:Phenobarbital has been shown to shorten the half- life ofdoxycyclinefor as long as 2 weeks after barbiturate therapy is discontinued. This mechanism is probably through the induction of hepatic microsomal enzymes that metabolize theantibiotic. If phenobarbital and doxycycline are administer...
Phenobarbital has the lowest lipid solubility, lowest plasma binding, lowest brain protein binding, the longest delay in onset activity, and the longest duration of action. The plasma half-life for phenobarbital in adults ranges between 53 and 118 hours with a mean of 79 hours. The plasma half...
Phenobarbital and primidone therapy may also lead to altered pharmacokinetics in concomitantly administered AEDs, whose metabolism may be increased, and lead to lowered plasma levels and/ or a shorter halflife: carbamazepine, ethosuximide, lamotrigine, oxcarbazepine, phenytoin, valproate, tiagabine, topir...