Medication Summary
The goals of pharmacotherapy are to reduce morbidity and to prevent complications.
Antivirals
Class Summary
Antivirals reduce progression of virus in the affected eye as well as protection of the other eye. [21]
Acyclovir (Zovirax)
Has affinity for viral thymidine kinase and once phosphorylated causes DNA chain termination when acted on by DNA polymerase. Patients experience less pain and faster resolution of cutaneous lesions when used within 48 h from rash onset. May prevent recurrent outbreaks. Early initiation of therapy is imperative.
Ganciclovir (Cytovene)
Synthetic guanine derivative active against cytomegalovirus (CMV). An acyclic nucleoside analog of 2'-deoxyguanosine that inhibits replication of herpes viruses both in vitro and in vivo.
Levels of ganciclovir-triphosphate are as much as 100-fold greater in CMV-infected cells than in uninfected cells, possibly due to preferential phosphorylation of ganciclovir in virus-infected cells.
For patients who experience progression of CMV retinitis while receiving a maintenance treatment with either dosage form of ganciclovir, the re-induction regimen should be administered.
Valacyclovir (Valtrex)
Prodrug rapidly converted to the active drug acyclovir. More expensive but has a more convenient dosing regimen than acyclovir.
Famciclovir (Famvir)
After ingestion, drug is rapidly biotransformed into active compound penciclovir and phosphorylated by viral thymidine kinase. By competition with deoxyguanosine triphosphate, penciclovir triphosphate inhibits viral polymerase subsequently inhibiting viral DNA synthesis/replication.
Adjust dose in patients with renal insufficiency or hepatic disease.
Used against herpes simplex and varicella-zoster viruses.
Foscarnet (Foscavir)
Analog of pyrophosphate. Inhibits DNA polymerase of CMV and reverse transcriptase of HIV. Virostatic; renal excretion. As effective as ganciclovir. Median time to relapse on Rx is 53 d. Foscarnet/ganciclovir CMV retinitis trial: 234 newly diagnosed patients randomized. Same efficacy for controlling retinitis and preserving vision. Survival with foscarnet 12.6 mo versus 8.5 for ganciclovir group; mortality risk 1.79x. Controlling for antiretroviral use, still better survival with foscarnet. Foscarnet has anti-HIV activity but has more dose-limiting toxicity.
Corticosteroids
Class Summary
These agents systemically interfere with events leading to inflammation.
Prednisone (Rayos)
May decrease inflammation by reversing increased capillary permeability and suppressing PMN activity.
Prednisolone (FloPred, Millipred, Millipred DP, Prelone)
Elicits mild mineralocorticoid activity and moderate anti-inflammatory effects; controls or prevents inflammation by controlling rate of protein synthesis, suppressing migration of polymorphonuclear leukocytes (PMNs) and fibroblasts, reversing capillary permeability, and stabilizing lysosomes at cellular level
Antiplatelets
Class Summary
Antiplatelets inhibit the cyclooxygenase system, decreasing the level of thromboxane A2, which is a potent platelet activator.
Aspirin (Bayer Aspirin, Ascriptin, Aspirtab, Buffinol, Buffasal)
Treats mild to moderate pain and headache. Inhibits prostaglandin synthesis, which prevents formation of platelet-aggregating thromboxane A2.
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The white area is necrotic retina.
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Severe vitritis with occlusive arteriolitis.
