Guidelines for use of oral ganciclovir in treatment of CMV retinitis

Confirm the diagnosis

Consult an ophthalmologist, preferably one experienced in ocular disease associated with HIV infection.

Choose induction treatment

Either IV ganciclovir or foscarnet. In specific instances where these therapies cannot be given, investigational approaches may be considered. These include intraocular injections of ganciclovir or foscarnet, intraocular ganciclovir implant and cidofovir.

Induction

IV induction therapy must be carried out for at least 3 weeks. Oral ganciclovir is indicated for maintenance therapy only after induction with IV ganciclovir.
Ganciclovir IV at 5 mg/kg every 12 h for the first 2 weeks then 5 mg/kg daily or every 12 h in the third week.
Withhold zidovudine (AZT) during induction because of additive myelosuppressive effects.
For management of neutropenia:

Consider the elimination of other myelosuppressive agents, or
Add G-CSF, or
Switch induction treatment to IV foscarnet.
IV ganciclovir should be discontinued if absolute neutrophil count falls below 500 cells/µL.

Switching to maintenance treatment

All areas of retinitis should be stable before switching.
Patients who are not stable after 4 weeks of induction should receive alternative therapy (e.g., foscarnet).
Ensure that the following are not present:

Zone 1 disease, as it is associated with greater risk of visual loss. Zone 1 includes the macula and
optic disc.
Blindness in the other eye.
Extraocular CMV disease.
Moderate to severe diarrhea, which may impair drug absorption.

Maintenance treatment with oral ganciclovir

Dose: 1000 mg orally three times daily.

Be aware of any concomitant treatment that may cause drug interactions.
Follow appropriate clinical and laboratory monitoring guidelines.
Consider dose reduction for renal impairment, if necessary.

Managing relapses

On first relapse, return to IV ganciclovir reinduction.
If a second or subsequent relapse occurs, reinduction should be carried out with IV ganciclovir or other agents, such as foscarnet or investigational therapy (e.g., intraocular ganciclovir, cidofovir, intraocular sustained-release ganciclovir implant or a combination of foscarnet and ganciclovir).
Always consider whether zone 1 or extraocular disease or diarrhea is present each time a switch to oral maintenance therapy is considered.