Antituberculosis drugs

Rifampin: Dosage and Administration

Rifampin usually is administered orally. When oral therapy is not feasible, the drug may be given by IV infusion. Rifampin should not be administered IM or subcutaneously since local irritation and inflammation can occur. Rifampin should be given orally either 1 hour before or 2 hours after a meal with a full glass of water to ensure maximum absorption.

Rifabutin: Uses

Prevention of disseminated MAC disease is an important goal in the management of patients with HIV infection and low helper/inducer (CD4+, T4+) T-cell counts because of the frequency with which the disease occurs in such patients and its associated morbidity. Current evidence indicates that MAC causes disseminated disease in a substantial proportion of HIV-infected patients and that prophylaxis with rifabutin, alone or combined with azithromycin, can reduce substantially the frequency of M. avium complex bacteremia and ameliorate clinical manifestations of the disease in patients with AIDS.


Rifabutin, a semisynthetic spiropiperidyl derivative of rifamycin S, is an ansamycin antibiotic. The drug is active in vitro and in vivo against Mycobacterium avium complex (MAC), including isolates obtained from patients with acquired immunodeficiency syndrome (AIDS).


Pyrazinamide, a derivative of niacinamide, is a synthetic antituberculosis agent. Pyrazinamide is used in conjunction with other antituberculosis agents in the treatment of clinical tuberculosis.

Isoniazid – Antituberculosis Agent

Isoniazid usually is administered orally. The drug may be given by IM injection when oral therapy is not possible. The fixed-combination preparation containing isoniazid and rifampin (Rifamate®) and the fixed-combination preparation containing isoniazid, rifampin, and pyrazinamide (Rifater®) should be given either 1 hour before or 2 hours after a meal; the manufacturer states that Rifater® should be given with a full glass of water.

Isoniazid: Cautions

Peripheral neuritis, usually preceded by paresthesia of the feet and hands, is the most common adverse effect of isoniazid and occurs most frequently in malnourished patients and those predisposed to neuritis (e.g., alcoholics, diabetics). Rarely, other adverse nervous system effects have also occurred including seizures, toxic encephalopathy, muscle twitching, ataxia, stupor, tinnitus, euphoria, memory impairment, separation of ideas and reality, loss of self-control, dizziness, and toxic psychosis. Neurotoxic effects may be prevented or relieved by the administration of 10-50 mg of pyridoxine hydrochloride daily during isoniazid therapy, and pyridoxine should be administered in malnourished patients, pregnant women, and those predisposed to neuritis (e.g., HIV-infected individuals).