May see depression at lower dosages. May see increase in drinking, urinating, and eating. Sedation and staggering may occur at higher dosages. Infrequently seen are liver damage and anemia . In a chemistry panel , certain enzymes produced by the liver are often elevated.
Addiction is possible with long-term use.
Not for use in pregnant or nursing animals. Phenobarbital may decrease the effect of oral anticoagulants, chloramphenicol, corticosteroids , doxycycline, griseofulvin, beta blockers , quinidine, theophylline, and metronidazole. Phenobarbital may increase or decrease the metabolism of phenytoin. Rifampin may decrease the effect of phenobarbital. No known food interactions.