ICD-10 Specific code A17.9: Tuberculosis of nervous system, unspecified

Ethambutol is bacteriostatic. It is effective against Mycobacterium tuberculosi and M.bovis with an MIC of 0.5–8µg per ml. The exact mechanism of action is unknown. While it has activity against some atypical mycobacteria including M.Kansasii, activity against other micro-organisms has not yet been reported.

Ethionamide is bacteriostatic against M. tuberculosis at therapeutic concentrations, but may be bactericidal at higher concentrations. The exact mechanism of action of ethionamide has not been fully elucidated, but the drug appears to inhibit peptide synthesis in susceptible organisms. Drug resistance develops rapidly when ethionamide is given as monotherapy.

Isoniazid is used mainly in the treatment of pulmonary tuberculosis but it appears to be effective also in the treatment of extrapulmonary lesions, including meningitis and genito-urinary disease.

Minocycline is a semi-synthetic derivative of tetracycline. Minocycline inhibits protein synthesis in susceptible bacteria. In common with other tetracyclines it is primarily bacteriostatic and has a similar spectrum of activity to other tetracyclines.

Rifampicin is an active bactericidial antituberculosis drug which is particularly active against the rapidly growing extracellular organisms and also has bactericidial activity intracellularly. Rifampicin inhibits DNA-dependent RNA polymerase activity in susceptible cells. Specifically, it interacts with bacterial RNA polymerase but does not inhibit the mammalian enzyme.

Streptomycin is a broad spectrum aminoglycoside antibiotic derived from Streptomyces griseus with antibacterial activity. It acts by interfering with normal protein synthesis. Streptomycin is typically used for treatment of active tuberculosis, always in combination with other antituberculosis agents.