<unk>  is used in combination with other antituberculosis agents as part of a second-line regimen for active tuberculosis.<unk>  is well absorbed orally with or without food, but is often administered with food to improve tolerance. It crosses the blood brain barrier to achieve concentrations in the cerebral-spinal fluid equivalent to plasma. The antimicrobial spectrum of<unk>  includes M. tuberculosis, M. bovis and M. segmatis. It also is used rarely against infections with M. leprae and other nontuberculous mycobacteria such as M. avium and M. kansasii. While working in a similar manner to isoniazid, cross resistance is only seen in 13% of strains, since they are both prodrugs but activated by different pathways. Resistance can emerge from mutations in ethA, which is needed to activate the drug, or ethR, which can be overexpressed to repress ethA. Mutations in inhA or the promoter of inhA can also lead to resistance through changing the binding site or overexpression. The FDA has placed it in pregnancy category C, because it has caused birth defects in animal studies. It is not known whether<unk>  is excreted into breast milk.
Ethionamide
Dimethyllysergamide
Triparanol
Phenoxyethanol
Chloroxylenol
Iodixanol
Flonicamid
Phenethylamine