“…Drugs such as barbiturates, bernegride, chloramphenicol, chlordiazepoxide, chloroquine, chlorpropamide, danazol, diazepam, ergot preparations, estrogens, ethanol excess, griseofulvin, halothane, hydantoins, imipramine, ketamine, meprobamate, methyldopa, methyprylon, methsuximide, nikethamide, oral contraceptives, pentazocine, phensuximide, phenylbutazone, progestogens, pyrazinamide, pyrazolone derivatives, sulfonamides, theophylline derivatives, tolbutamide, troxidone and valproic acid (Bonkowsky et al, 1982) have been reported to exacerbate acute porphyrias. These drugs should thus be administered with caution in patients with an encephalopathy associated with porphyria.…”