Author: Brian Holtry

In addition, HIV protease inhibitors and some NNRTIs (e.g., delavirdine) reduce the metabolism of rifamycins, leading to increased plasma concentrations of rifamycins and an increased risk of toxicity. The potential for alterations in the plasma concentrations of antimycobacterial agent(s) and/or antiretroviral agent(s) must be considered when antimycobacterial agents are indicated for the management of latent or active tuberculosis or the prophylaxis or treatment of Mycobacterium avium complex (MAC) infections in HIV-infected patients who are receiving or are being considered for antiretroviral therapy. Although pharmacokinetic data and clinical experience are limited, some experts state that concomitant use of ritonavir (with or without saquinavir) and usual dosages of rifampin for the treatment of tuberculosis (600 mg daily or 2 or 3 times weekly) is a possibility. These experts state that rifampin can be used for the treatment of active tuberculosis in patients receiving an antiretroviral regimen that includes ritonavir and one or more nucleoside reverse transcriptase inhibitors.

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).

Rifabutin is administered orally. Administration of rifabutin with a high-fat meal decreases the rate but not the extent of absorption. Therefore, the drug generally can be given orally without regard to meals.

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.

Cycloserine, a structural analog of the amino acid d-alanine, is an antituberculosis antibiotic. Cycloserine is used in conjunction with other antituberculosis agents in the treatment of clinical tuberculosis.

Capreomycin, a polypeptide antibiotic complex of 4 microbiologically active components, is an antituberculosis agent. Capreomycin is used in conjunction with other antituberculosis agents in the treatment of clinical tuberculosis.

Aminosalicylic acid is used in conjunction with other antituberculosis agents in the treatment of clinical tuberculosis. The drug is designated an orphan drug by the US Food and Drug Administration (FDA) for use in the treatment of tuberculosis. These regimens have a minimum duration of 6 months (26 weeks), and consist of an initial intensive phase (2 months) and a continuation phase (usually either 4 or 7 months). Aminosalicylic acid is considered a second-line antituberculosis agent for use in these regimens.

Antituberculosis agents are antibiotics and synthetic anti-infectives used in the treatment of tuberculosis and other diseases caused by organisms of the genus Mycobacterium. Isoniazid, rifampin, ethambutol, and pyrazinamide are the drugs used most frequently in the treatment of tuberculosis and are considered first-line agents for use in antituberculosis regimens.