Concomitant ganciclovir and zidovudine treatment for cytomegalovirus retinitis in patients with HIV infection: an approach to treatment.

Cytomegalovirus (CMV) retinitis is the most common cause of blindness in patients infected with human immunodeficiency virus (HIV). Ganciclovir, a guanosine nucleoside, has been found to be effective in the short-term treatment of CMV retinitis and in the delay of progression to recurrence of the disease. However, ganciclovir has no intrinsic activity against HIV, and patients with the acquired immune deficiency syndrome often require treatment with zidovudine, the only currently approved therapy for HIV infection. Both agents have been associated with dose-limiting granulocytopenia in such patients, and death from sepsis in the setting of profound decreases in absolute granulocyte counts has been reported. However, recent investigation suggests that with careful patient selection and monitoring, relatively safe concomitant therapy may be possible. This article reviews the toxicity issues that influence the decision to employ concomitant therapy with ganciclovir and zidovudine. An approach to dosing ganciclovir, including a schema for modifying or interrupting the zidovudine dosage based on hematologic status, is also presented. A prospective study is presently under way to determine whether combined therapy in selected patients leads to prolonged survival and a decreased incidence of recurrence of active CMV retinitis.