May color skin and bodily secretions or excretions orange brown. Permanently stains contact lenses. Drug interactions Induces hepatic isoforms of cytochrome P450, but half to a third as potent as rifampin. Kinetics of didanosine and fluconazole appear unaffected. Because is similar to rifampin, should suspect of altering pharmacokinetics of many compounds.
Resistance develops rapidly when used alone.
Death due to hepatic necrosis can occur. Resistance to ethambutol develops slowly. May appear as early as 24 h or 90 days after start therapy. May be worsened by isoniazid and pyridoxine. Also inhibits other organisms, e.g., Enterococci, E. coli, Staphylococcus aureus, Nocardia spp.