Valganciclovir: new preparation. CMV retinitis: a simpler, oral treatment

For AIDS patients with cytomegalovirus (CMV) retinitis, the standard initial treatment has so far been ganciclovir or foscarnet, both of which are infused intravenously. The choice between these two antiviral agents is based on their differing side effects. Maintenance treatment is based on ganciclovir or foscarnet, but both these drugs must be given as daily intravenous infusions. Oral ganciclovir is less effective. Intraocular maintenance treatment in appropriate only for patients with localised infections and a low risk of relapse. Valganciclovir can be taken orally for both initial and maintenance treatment of CMV retinitis. Valganciclovir has good bioavailability and is rapidly metabolised into ganciclovir. A comparative randomised trial in 160 patients showed that oral valganciclovir is as effective as intravenous ganciclovir when used as an initial treatment. There are no comparative trials of oral valganciclovir as a maintenance treatment, but non comparative data and pharmacokinetic studies suggest that oral valganciclovir is about as effective as intravenous ganciclovir. The adverse effects of oral valganciclovir are similar to those of intravenous ganciclovir, except that the oral route avoids the risk of local complications at the infusion site. Valganciclovir causes more frequent diarrhoea and oral candidosis than intravenous ganciclovir. In practice, for patients with CMV retinitis who require systemic treatment, oral valganciclovir is easier to use and, in our opinion, should now replace IV ganciclovir for both initial and maintenance treatment. The convenience of oral valganciclovir should also limit the use of purely intraocular treatment of CMV retinitis.