by exhalation via the lungs. Indication Iproniazid was originally produced as anti-tuberculosis medicine, but found to be more effective as antidepressant. When it was discovered that iproniazid is hepatotoxic, it was replaced by medicinal xenobiotics that are less harmful to the liver. Examples of antidepressant drugs that are nowadays used instead of iproniazid are isocarboxazid, phenelzine, and tranylcypromine. Drugs more effective for treatment of tuberculosis are isoniazid, pyrazinamide, ethambutol and rifampicin. Efficacy and side effects Efficacy Iproniazid was designed to treat tuberculosis, but its most significant positive effect is that it has a mood-stimulating property. Therefore, it was used as an antidepressant drug. Adverse effects The most significant adverse effects of using iproniazid is the hepatotoxicity caused by its metabolites. Moreover, usage of iproniazid results in several adverse effects such as dizziness (when lying down), drowsiness, headaches, ataxia, numbness of the feet and hands, and muscular twitching. However, these adverse effects disappear after approximately 10 weeks. Effects on animals Rat animal models have been used to investigate the hepatotoxic (bio)chemical mechanism of iproniazid. A metabolite of iproniazid, isopropyl hydrazine, was found to be a potent hepatotoxin in rats. Hepatic necrosis was found in rats with doses as low as 10 mg/kg. It was predicted with admetSAR that iproniazid had a LD50 of 2.6600 mol/kg in rats. Lethality See the table for experimentally determined LD50, TDLo and LDLo values of various organisms. See also Hydrazine (antidepressant) Isoniazid References Monoamine oxidase inhibitors Hepatotoxins Hydrazides 4-Pyridyl compounds Withdrawn drugs Isopropyl compounds