Treatment can be started as long as new lesions are forming. Preventive treatment must be initiated within 96 hours of exposure and preferrably within 48 hours. Oral ganciclovir should not be used as sole induction therapy. Foscarnet requires infusion pump, long infusion time, saline hydration. The same concern applies to fomivirsen injections.
Subsequent relapses occur more rapidly.
ACTG 228 showed no difference between reinduction with the same drug compared to switching to the alternative drug. If the ganciclovir implant fails, consider IV or intravitreal foscarnet. See above for median time to relapse for different initial regimens. May be complicated by cystoid macular edema, epiretinal membranes, and papillitis. Lower rate may be due to better CMV suppression before HaART started.