Pharmacology
Summary
Mycobacterium avium complex is a common cause of disseminated disease in late-stage AIDS patients where the CD4 count drops below 50. The typical treatment regimen includes a combination of the macrolides azithromycin or clarithromycin and ethambutol. Occasionally a third drug, rifabutin, related to rifampin and an activator of the cytochrome P450 system, may be added, especially in cases involving immunocompromised patients.
Mycobacterium leprae is the bacterium known to cause leprosy. This disease is commonly treated using a combination of drugs, with the most common one being dapsone. Notable side effects of dapsone include agranulocytosis and hemolytic anemia in patients with G6PD deficiency. Additional drugs used in a typical leprosy treatment regimen include Clofazimine is added to the regimen specifically for lepromatous leprosy. Additionally, rifampin is part of all treatment regimens for leprosy.
Lesson Outline
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FAQs
The Mycobacterium avium complex (MAC), which includes Mycobacterium avium and Mycobacterium intracellulare, is usually treated using a combination of a macrolide such as azithromycin or clarithromycin and ethambutol. In some cases, rifabutin may also be added as a third agent in the treatment of MAC infections.
Patients with AIDS often have weakened immune systems, leaving them more susceptible to infections like MAC. When the CD4 count drops below 50, the risk of MAC infection increases significantly, often resulting in disseminated disease. To prevent this, macrolide prophylaxis for MAC is typically initiated.
Rifampin and rifabutin are antibiotics that work by inhibiting the DNA-dependent RNA polymerase of mycobacteria, effectively stopping the synthesis of RNA and therefore the production of protein. Both drugs can activate cytochrome P450, which can lead to the induction of metabolizing enzymes that may affect the processing of other drugs and substances in the body.
Mycobacterium leprae, the causative agent of leprosy, is typically treated using dapsone and rifampin. In cases of lepromatous leprosy, clofazimine may also be used. Dapsone can cause side effects including agranulocytosis and hemolytic anemia in G6PD deficiency, the latter of which can be identified by the presence of bite cells and Heinz bodies in red blood cells.
Lepromatous leprosy, a form of leprosy caused by Mycobacterium leprae, often results in a characteristic 'leonine' (lion-like) appearance of the face. This is the result of the deposit of leproma (inflamed nodules) on the skin, which cause an alteration and thickening of facial features.
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