How is cytomegalovirus (CMV) retinitis in HIV infection treated?

Updated: Jul 21, 2021
  • Author: Luca Rosignoli, MD; Chief Editor: Andrew A Dahl, MD, FACS  more...
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Specific agents and modalities for the treatment of CMV retinitis include the following:

·       Oral valganciclovir

·       Oral, intravenous, and intravitreal ganciclovir

·       Intravenous and intravitreal foscarnet or combined intravenous ganciclovir and foscarnet

·       Intravenous and intravitreal cidofovir

These agents act by inhibiting CMV DNA polymerase.

Valganciclovir is the drug of choice for the treatment of CMV retinitis because of its convenience, lower cost, and lack of complications associated with IV administration. Valganciclovir is the valine ester of ganciclovir. The addition of the valine moiety increases the absorption of ganciclovir tenfold.

Valganciclovir is available as a 450-mg tablet. The recommended dose for induction is 900 mg twice a day and then 900 mg once a day for maintenance. Adverse effects are similar to those of intravenous ganciclovir and require periodic monitoring of complete blood count and renal function. Given the need for lifelong therapy for CMV retinitis in some HIV-positive patients, valganciclovir is a welcome alternative to long-term administration of intravenous antivirals.

Ganciclovir induction dosage is 5 mg/kg IV every 12 hours for 14 days. This is usually followed by a maintenance IV dose of 5 mg/kg/day for 7 days. Dosage should be adjusted for renal impairment. The significant adverse effect of ganciclovir therapy is myelosuppression. CBC with differential should be monitored 2-3 times a week during induction phase and weekly thereafter. If the absolute neutrophil count drops below 500/mL (see the Absolute Neutrophil Count calculator) or the platelet count drops below 10,000/mL, ganciclovir treatment should be discontinued

To prevent immunosuppression, zidovudine dosage may need to be reduced during treatment of CMV retinitis with ganciclovir, unless hematopoietic growth factors (eg, regramostim, filgrastim) are used concurrently.

Alternatively, intravitreal ganciclovir may be implanted to ensure adequate and prolonged intravitreal concentration of the drug. However, this does not preclude the use of oral ganciclovir to control the systemic infection.

Foscarnet induction dosage is 60 mg/kg IV every 8 hours for 14 days, followed by a maintenance IV dose of 90-120 mg/kg/day. Foscarnet can result in renal toxicity. Therefore, it is recommended that electrolyte status, particularly calcium and magnesium, serum creatine, and hemoglobin, be monitored 2-3 times per week for 2 weeks and weekly thereafter. Dosage adjustment is recommended if renal insufficiency is present, and the drug should be discontinued if serum creatine is greater than 2.8 mg/dL.

Cidofovir induction dosage 5 mg/kg IV over 1 hour once weekly for 2 weeks, followed by maintenance dose of 5 mg/kg over 1 hour once every other week. This drug is also nephrotoxic. Concurrent use of probenecid with cidofovir reduces the risk of renal toxicity. Other adverse effects of cidofovir include iritis and ocular hypotony. It is also a major risk factor for immune recovery uveitis (IRU) among patients with CMV retinitis who are receiving HAART. [28]

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