cough cough

isoniazid (INH) should never be prescribed as a monotherapy for TB (unless the patient has a positive PPD, but a negative CXR = no clinical manifestation of TB) because it can induce resistance via these two mechanisms:

• decrease bacterial expression of catalase peroxidase enzyme for INH inactivation once the drug enters the bacterial cell AND
• modification of protein target binding site of INH

 a mnemonic for remembering first line antiTB drugs:

If you forget your TB drugs, you'll die and might need a PRIEST
Pyrazinamide
Rifampin
Isoniazid (INH)
Ethambutol
STreptomycin