Protionamide is a thioamide derivative with antitubercular activity, usually involving to treat MDR TB and leprosy. It has the same active substances and cross-resistance with ethionamide. Prothionamide is part of a group of drugs thioamides. The side effects of prothionamide are similar to ethionamide. Prothionamide is most commonly associated with nausea and vomiting. It may cause depression and hallucinations. Rarely, prothionamide will cause jaundice, menstrual disturbances and peripheral neuropathy. Prothionamide has received approval in Germany for the treatment of TB and drug resistant TB. While prothionamide is widely used to treat MDR TB, there is little published evidence demonstrating safety and efficacy. Protionamide forms a covalent adduct with bacterial nicotinamide adenine dinucleotide (NAD), PTH-NAD, which competitively inhibits 2-trans-enoyl-ACP reductase (inhA), an enzyme essential for mycolic acid synthesis. This results in increased cell wall permeability and decreased resistance against cell injury eventually leading to cell lysis. Mycolic acids, long-chain fatty acids, are essential mycobacterial cell wall components and play a key role in resistance to cell injury and mycobacterial virulence.