From the Guidelines
Mycobacterium avium complex (MAC) infection should be treated with a multi-drug regimen consisting of clarithromycin 500mg twice daily or azithromycin 500mg daily, plus ethambutol 15mg/kg daily, and rifampin 600mg daily, continued for at least 12 months after culture conversion to negative, as recommended by the most recent guidelines 1. The treatment of MAC infection is challenging due to the bacterium's waxy cell wall and ability to form biofilms, which resist many antibiotics. The use of a multi-drug regimen is essential to prevent resistance development, which commonly occurs with single-drug therapy.
- The recommended treatment regimen includes a macrolide, such as clarithromycin or azithromycin, which has been shown to be effective against MAC infection 1.
- Ethambutol and rifampin are also essential components of the treatment regimen, as they have been shown to be effective in combination with macrolides 1.
- For severe or disseminated disease, adding amikacin or streptomycin during the initial phase may be necessary, as recommended by the guidelines 1.
- Treatment should be monitored with monthly sputum cultures until conversion occurs, and side effects such as visual changes with ethambutol, gastrointestinal disturbances with macrolides, and liver function abnormalities with rifampin should be watched for 1.
- Immunocompromised patients, particularly those with HIV and CD4 counts below 50 cells/mm³, should receive prophylaxis with azithromycin 1200mg weekly or clarithromycin 500mg twice daily to prevent MAC infection, as recommended by the guidelines 1.
From the FDA Drug Label
Antimicrobial Activity Clarithromycin has been shown to be active against most of the isolates of the following microorganisms both in vitroand in clinical infections [see Indications and Usage (1)] ... Mycobacterium avium complex (MAC) consisting of M. avium and M intracellulare
The treatment for Mycobacterium avium complex (MAC) infection is clarithromycin 2.
From the Research
Treatment Regimens for Mycobacterium avium Complex (MAC) Infection
- The recommended treatment regimens for MAC infection include a combination of antibiotics, such as a macrolide (e.g., clarithromycin or azithromycin) and a rifamycin (e.g., rifabutin), with or without ethambutol 3, 4, 5, 6, 7.
- A study published in 2003 found that treatment with a macrolide, ethambutol, and clofazimine was successful in 20 of 30 patients (67%) with MAC lung disease 3.
- Another study published in 1995 recommended using rifabutin at a dose of 300 mg/d in multidrug regimens that include a macrolide for treatment of MAC lung disease, due to adverse events associated with high-dose rifabutin 4.
- For patients with AIDS, current recommendations include treating disseminated MAC disease with at least two agents, with oral clarithromycin or azithromycin as the preferred first agent, and ethambutol as the most rational choice for the second agent 5, 7.
- Macrolides, such as clarithromycin and azithromycin, are active agents against MAC, but monotherapy is usually associated with the emergence of drug resistance, and combination therapy is recommended 6.
Combination Therapy
- Combination therapy with a macrolide and other antibiotics, such as rifabutin, moxifloxacin, and/or ethambutol, is recommended for the treatment of MAC infection 6, 7.
- The use of ketolides, such as telithromycin, has also been studied and shown to be active against MAC in mice models 6.