General: In order to control, MAC, the immune system must be restored. Therefore, all patients who are not taking antiretroviral therapy (ART) should begin treatment. In general, MAC infection is treated with two or three antimicrobials for life in order to prevent the infection from recurring. HIV patients who have DMAC infections usually receive a combination of newer macrolide antibiotics (clarithromycin, azithromycin) with ethambutol and rifabutin.
Antimicrobials: The U.S. Centers for Disease Control and Prevention (CDC) recommends the following two drug regimens: 500mg of the macrolide antibiotic clarithromycin (Biaxin®) twice daily, plus 15mg/kg of ethambutol (Myambutol®) once daily, or 500-600mg of azithromycin (Zithromax®) once daily, plus 15mg/kg of ethambutol (Myambutol®) once daily. Several studies suggest that azithromycin can effectively treat 55-60% of MAC infections. Higher doses of clarithromycin (1000mg or more) are associated with higher mortality rates.
Other antimicrobials commonly prescribed include rifabutin (Mycobutin®), levofloxacin (Levaquin®) and amikacin (Amikin®).
Patients who have MAC will continue treatment for life in order to prevent the infection from recurring.
Highly active antiretroviral therapy (HAART): When HIV reproduces, different strains of the virus emerge, and some are resistant to antiretroviral drugs. Therefore, it is common for healthcare providers to recommend a combination of antiretroviral drugs known as HAART. This strategy, developed by NIAID-support researchers, usually combines drugs from at least two different classes of antiretroviral drugs, and it has been shown to suppress the virus. While these drugs cannot cure HIV infection or AIDS, they can suppress the virus.
Currently, the U.S. Food and Drug Administration (FDA) has approved 28 antiretroviral drugs to treat HIV infected individual. These drugs fall into three major classes: reverse transcriptase (RT) inhibitors, fusion inhibitors and protease inhibitors. In July 2006, the FDA approved a multi-class combination called Atripla®.
Fusion inhibitors prevent the virus from fusing with the cellular membrane, thus blocking entry into the cell. Only one fusion inhibitor, Fuzeon®, is FDA-approved.
Protease inhibitors interfere with the protease enzyme that HIV uses to produce infectious viral particles. They are a class of medication used to treat or prevent infection by viruses, including HIV and Hepatitis C. PIs prevent viral replication by inhibiting the activity of protease, an enzyme used by the viruses to cleave nascent proteins for final assembly of new virons.
FDA-approved protease inhibitors include Agenerase®, Aptivus®, Crixivan®, Invirase®, Kaletra®, Lexiva®, Norvir®, Prezista®, Reyataz® and Viracept®.
Reverse transcriptase (RT) inhibitors disrupt the reverse transcription stage in the HIV lifecycle. During this stage, an HIV enzyme, known as reverse transcriptase, converts HIV RNA to HIV DNA. There are two main types of RT inhibitors. Non-nucleosideRT inhibitors bind to reverse transcriptase, preventing HIV from converting the HIV RNA into HIV DNA. Approved non-nucleoside RT inhibitors include Rescriptor®, Sustiva® and Viramune®.
Nucleoside/nucleotide reverse transcriptase inhibitors
serve as faulty DNA building blocks, and once they are incorporated into the HIV DNA, the DNA chain cannot be completed. Therefore, the drugs prevent HIV from replicating inside a cell. Approved antiretrovirals include Combivir®, Emtriva®, Epivir®, Epzicom®, Hivid®, Retrovir®, Trizivir®, Truvada®, Videx EC®, Videx®, Viread®, Zerit® and Ziagen®.
Probiotics: Limited evidence with day care children suggests supplementation with Lactobacillus GG may reduce number of sick days, frequency of respiratory tract infections and frequency of related antibiotic treatments. Fermented milk (with yogurt cultures and L. casei DN-114001) may reduce the duration of winter infections (gastrointestinal and respiratory), as well as average body temperature, in elderly people.
Probiotics are generally considered safe and well tolerated. Avoid if allergic or hypersensitive to probiotics. Use cautiously if lactose intolerant.
Unclear or conflicting scientific evidence
Bladderwrack: Laboratory studies suggest that bladderwrack has antifungal and antibacterial properties. However, there are no reliable human studies to support use as an antibacterial or antifungal agent.
Blessed thistle: Laboratory studies report that blessed thistle (and chemicals contained in blessed thistle, such as cnicin and polyacetylene) may have activity against several types of bacteria and no effects on some types. Reliable human study is lacking. Further evidence is necessary in this area before a firm conclusion can be drawn.
Cranberry: Study results of cranberry as an antibacterial in other conditions show conflicting results. Further study is needed before a conclusion can be drawn.
Lavender: Early laboratory studies suggest that lavender oils may have antibiotic activity. However, this has not been well tested in animal or human studies.
Probiotics: As a bacterial reservoir, the nose may harbor many types of disease-causing bacteria. There is limited evidence that probiotic supplementation may reduce the presence of harmful bacteria in the upper respiratory tract. More studies are needed to establish this relationship and its implications for health.
Sorrel: There are no well-conducted published studies that demonstrate sorrel to possess activity against viruses or bacteria that are important human pathogens.
General: Preventative therapy is usually recommended for AIDS patients who have a CD4 cell count lower than 50 cells per microliter of blood. Based on the most recent research, clarithromycin appears to be the most effective drug for the prevention of MAC.
Clarithromycin (Biaxin®): Clarithromycin (Biaxin®) is FDA-approved for the prevention of MAC. Studies have shown that the drug reduces the number of MAC infections by 69%.
Clarithromycin is considered to be the most effective drug for the prevention of MAC. However, some researchers are concerned that if a person develops MAC while taking clarithromycin, the infection will be resistant to treatment. According to several studies, about 50% of patients who developed MAC while taking clarithromycin developed MAC infections that were resistant to the drug.
Rifabutin (Mycobutin®): According to a multi-center trial, rifabutin (Mycobutin®) can reduce the rate of MAC by almost 50% in AIDS patients. Several other studies show that the drug may help people live longer lives. Researchers have shown that taking rifabutin as a preventative treatment reduces the risk of fatality by 14%. The most serious side effects of rifabutin are low white blood cells counts and elevated liver enzymes.
Azithromycin (Zithromax®): Azithromycin (Zithromax®) is the most recent drug to be FDA-approved for the prevention of MAC. This drug can be taken once a week due to its long half-life. One study found that azithromycin was more effective than rifabutin. The efficacy of azithromycin has not been compared to clarithromycin in studies.