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

Updated: Jun 12, 2019
  • Author: Robert A Copeland, Jr, 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, 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.

When using ganciclovir, start induction with 5 mg/kg IV every 12 hours for 14 days, then change to a maintenance IV dose of 5 mg/kg/day for 7 days. Adjust the dose accordingly for patients with renal insufficiency. The significant adverse effect with ganciclovir is myelosuppression. Monitor CBC with differential 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, discontinue ganciclovir treatment.

During the treatment of CMV retinitis with ganciclovir, the dose of zidovudine may need to be reduced, unless hematopoietic growth factors (eg, regramostim, filgrastim) are used concurrently. This prevents exacerbation of myelosuppression.

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.

When using foscarnet, start induction with 60 mg/kg IV every 8 hours for 14 days, then change to a maintenance IV dose of 90-120 mg/kg/day. Hydration with 1000 mL of isotonic sodium chloride solution is recommended because of renal toxicity associated with foscarnet. 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.

When using cidofovir, start induction with 5 mg/kg IV over 1 hour once weekly for 2 weeks, then change to a maintenance dose of 5 mg/kg over 1 hour once every other week. This drug is nephrotoxic. Concurrent use of probenecid with cidofovir and hydration with 1-2 L of normal saline 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. [26]

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