Treatment regimens Until the introduction of the new, 4-month regimen, treatment of all patients with new, previously untreated TB had consisted of the following: 2-month initial intensive phase 4 - to 7-month continuation phase Initial intensive-phase therapy is with 4 antibiotics (see table for dosing): Isoniazid (INH) Rifampin (RIF) Pyrazinamide (PZA) Ethambutol (EMB) These drugs can be given daily throughout this 2-month phase or daily for 2 weeks, followed by doses 2 or 3 times / week for 6 weeks.