When rifabutin is used as prophylaxis for MAC, an opportunistic infection seen frequently in AIDS patients, uveitis is rarely seen. However, when rifabutin is used in combination with clarithromycin or azithromycin, the incidence of uveitis increases. During the CTN's recently completed MAC study, our researchers discovered an increased incidence of uveitis among people on the three-drug arm receiving rifabutin, clarithromycin and ethambutol. When the dosage of rifabutin was decreased from 600 mg to 300 mg, there were only 3 additional reported cases of uveitis in 53 patients randomized to the three drug arm. Uveitis makes it difficult or impossible to read or drive, for example, seriously affecting a patient's quality of life.
Symptoms usually improve shortly after treatment begins.
Rarely, untreated uveitis can result in blindness. While uveitis was initially of great concern with the high dose rifabutin treatment, it has proven to be relatively easy to treat. It is important to keep our perspective.