Phenobarbital appears to interfere with the absorption of orally administered griseofulvin, thus decreasing its blood level. Barbiturates lower serum bilirubin concentrations Con neonates and patients with congenital nonhemolytic unconjugated hyperbilirubinemia, presumably by induction of glucuronyl transferase, the enzyme that conjugates bilirubin. Sodium valproate and valproic acid ... https://euthanasiameds.com