Retinitis viral

CMV, a virus of the herpes family, isa common viral infection. Healthy individuals may beoome infected yet have no symptoms. However, immunocompromised patients (such as those with HIV or cancer) may have the infection. Symptoms include malaise, fever, pneumonia, and super infection. Infants may acquire the virus from the mother while in the uterus, resulting in learning disabilities and mental retardation. CM V can infect the eye, causing retinitis. Symptoms of CMV retinitis are blurred vision and decreased visual acuity. Visual impairment is irreversible and can lead to blindness if untreated. 

Antiviral drugp interfere with viral reproduction by altering DNA synthesis. These drug are used in the treatment of herpes simplex infections of the eye, treatment in immunocompromised patients with cytomegalovirus (CMV) retinitis, and for the prevention of CMV retinitis in patients undergoing transplant. 

Jabs DA (1995) Ocular manifestations of HIV infection. Trans Am Ophthalmol Soc 93 623-683 Jabs DA, Enger C, Dunn JP, Forman M (1998a) Cytomegalovirus retinitis and viral resistance ganciclovir resistance. J Infect Dis 177 770-773... 

WARNING Renal impair is the major tox foUow administration instructions Uses CMV retinitis w/ HIV Action Selective inhibition of viral DNA synth Dose Rx 5 mg/kg IV over 1 h once/wk for 2 wk w/ probenecid Maint 5 mg/kg IV once/2 wk w/ probenecid (2 g PO 3 h prior to cidofovir, then 1 g PO at 2 h 8 h after cidofovir) X in renal impair Caution [C, -] Contra Probenecid or sulfa allergy Disp Inj SE Renal tox, chills, fever, HA, NA /D, thrombocytopenia, neutropenia Interactions t Nephrotox W/ aminoglycosides, amphot icin B, foscar-net, IV pentamidine, NSAIDs, vancomycin t effects W/zidovudine EMS Monitor ECG for hypocalcemia (t QT int val) and hypokalemia (flattened T waves) OD May cause renal failure hydration may be effective in reducing drug levels/effects Cilostazol (Pletal) TAntiplatelet, Arterial Vasodilator/ Phosphodiesterase Inhibitor] Uses Reduce Sxs of intermittent claudication Action Phosphodiesterase in inhibitor t s cAMP in pits blood vessels, vasodilation inhibit pit aggregation Dose 100 mg PO bid, 1/2 h before or 2 h after breakfast dinner Caution [C, +/-] Contra CHE, hemostatic disorders. 

Foscarnet (Foscavir) [Antiviral] Uses CMV retinitis acyclovir-resistant hCTpes Infxns Action -1- Viral DNA polym ase RT Dose CMV retinitis Induction 60 mg/kg IV qSh or 100 mg/kg ql2h X 14—21 d Meant 90-120 mg/kg/dIV (Moo.-Fiti ) Acyclovir-resistant HSV Induction 40 mg/kg IV q8-12h x 14—21 d use central line -1- w/ renal impair Caution [C, —] T Sz potential w/ fluoroquinolones avoid n hrotoxic Rx (cyclosporine, aminoglycosides, ampho B, protease inhibitors) Contra CrCl <0.4 mL/min/kg Disp Inj SE Nephrotox, electrolyte abnormalities Interactions T Risks of Sz W/ quinolones t risks of n hrotox W/ aminoglycosides, amphotCTicin B, didanosine, pentamidine, vancomycin EMS Known to cause electrolyte disturbances (extremity numbness paresthesia indicates electrol5rte unbalance) monitor ECG OD May cause extremity numbing, and Szs hydrate w/ IV fluids... 

Foscarnet sodium is an pyrophosphate analogue. It inhibits viral DNA polymerase and reverse transcriptase. Its main indication is cytomegalovirus retinitis in AIDS patients which have contraindications for ganciclovir. 

In 1996 cidofovir was approved for the treatment of AIDS-related cytomegalovirus retinitis. It is already a monophosphate and does not need activation by viral enzymes. 

Cidofovir is approved for the treatment and prophylaxis of CMV retinitis in AIDS patients. It has also been used in the treatment of acyclovir-resistant (viral thymidine kinase-dehcient) HSV infections, polyomavirus-associated progressive multifocal leukoencephalopathy, condylomata acuminata (anogenital warts), and mollus-cum contagiosum. 

Mechanism of Action Inhibits replication by interfering with viral DNA synthesis CMV retinitis in immunocompromised patients... 

Cidofovir inhibition of viral DNA polymerase Cytomegalovirus indicated only for virus-induced retinitis 2-3 ... 

As mentioned above, intravitreal injection of drugs should be used in many cases to achieve therapeutic intravitreal drug levels. This is especially true for cases of viral retinitis, such as cytomegalovirus (CMV) retinitis and acute retinal necrosis (ARN) which require intravitreal injection of antivirals, or for the treatment of bacterial and fungal endophthalmitis or proliferative vitreoretinopathy [305]. It still remains a controversial issue whether liposomes can reach the retina after intravitreal injections and which vesicle physicochemical characteristics should be preferred for such formulations. 

Ganatra JB, Chandler D, Santos C, et al. Viral causes of the acute retinal necrosis syndrome. Am J Ophthalmol 2000 129 166. 

Retinal complications of interferon alfa in chronic viral hepatitis patients are well known, but few cases have been described with interferon beta. 

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