Maraviroc is primarily used in the treatment of HIV infection. It works by blocking the CCR5 receptor on the surface of immune cells, which prevents the HIV virus from entering and infecting these cells. This makes it particularly effective against CCR5-tropic HIV-1 strains. It is often prescribed as part of combination antiretroviral therapy (ART) to manage and control the progression of HIV, helping to reduce viral load and improve immune function. Maraviroc is typically used in patients who have already been treated with other HIV medications and have shown resistance or intolerance to them. It is also used in cases where the specific HIV strain is known to be CCR5-tropic, as determined by a tropism assay. The drug is administered orally and is generally well-tolerated, though it may have side effects such as dizziness, liver issues, or allergic reactions. Regular monitoring is required to ensure its effectiveness and safety during long-term use.