The Food and Drug Administration approved oral ganciclovir (Cytovene capsules) for treating CMV retinitis on December 22, 1994. The drug is marketed by Syntex Laboratories, Inc., Palo Alto, California. Intravenous ganciclovir (Cytovene-IV) has been approved for the treatment of CMV retinitis since June, 1989.
CMV retinitis can cause blindness in persons with advanced AIDS. The primary advantage of oral ganciclovir is that it negates the need for daily infusion of drug, which carries risk of serious infection. The newly-approved oral drug can be used for maintenance in some patients; however, intravenous administration is still necessary for initial therapy.
Ganciclovir capsules have been shown to be less effective than the intravenous form because of lower bioavailability. In clinical trials, the average time to disease progression was five to twelve days faster with the oral drug. Because the oral form is associated with risk of more rapid CMV progression, it should be used only in those patients for whom this risk is balanced by the benefit associated with avoiding daily intravenous infusions. Many of the side effects of intravenous ganciclovir are still present with the oral drug, including hematological toxicities; therefore blood tests are necessary with the oral as with the intravenous treatment.
Oral ganciclovir should be taken with food to maximize bioavailability.