Valacyclovir inhibits recovery of ocular HSV-1 after experimental reactivation by excimer laser keratectomy.
OBJECTIVE
The goal of this was to determine whether the systemic administration of valacyclovir (Valtrex) would reduce ocular shedding of herpes simplex virus 1 (HSV-1) after excimer laser ablation in the New Zealand rabbit latency model.


METHODS
The in vitro 50% inhibitory concentration (IC50) of HSV-1 W strain was determined by using a plaque-reduction assay to verify its sensitivity to acyclovir. Forty-seven NZW rabbits latently infected with HSV-1 W strain were divided into four groups: I, 50 mg/kg/day valacyclovir; II, 100 mg/kg/day valacyclovir; III, 150 mg/kg/day valacyclovir; and IV, saline control. One half of the total dose of valacyclovir was delivered via intraperitoneal injections twice daily for 7 days beginning with one dose before excimer laser keratectomy. HSV-1 ocular shedding was determined from eye cultures for 7 days after treatment.


RESULTS
The IC50 for HSV-1 W was determined to be 2.9 microg/ml. The administration of both 100 mg/kg/day (group II) and 150 mg/kg/day (group III) of valacyclovir significantly reduced the number of eyes from which latent HSV-1 was recovered compared with the control group. There was no difference between the control group and group I (50 mg/kg/day valacyclovir). However, all three valacyclovir dosages significantly reduced the total number of HSV-1 shedding days compared with the control group, and 100% HSV-1 TG latency was demonstrated for all four groups.


CONCLUSIONS
Systemic administration of valacyclovir significantly reduced HSV-1 ocular shedding in a dose-dependent manner after excimer laser keratectomy in the NZW rabbit latency model.
Dhaliwal
D K
DK
Department of Ophthalmology, University of Pittsburgh School of Medicine, Pennsylvania 15203, USA. dhaliwal@vision.eei.upmc.edu
Romanowski
E G
EG
Yates
K A
KA
Barnhorst
D A
DA
Goldstein
M
M
Deeter
R G
RG
Fish
D N
DN
Gordon
Y J
YJ
D000212:Acyclovir / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology; D000818:Animals; D000998:Antiviral Agents / Q000097:blood / Q000494:pharmacology*; D003315:Cornea / Q000601:surgery*; D005123:Eye / Q000821:virology*; D005260:Female; D018259:Herpesvirus 1, Human / Q000187:drug effects* / Q000254:growth & development*; D020128:Inhibitory Concentration 50; D053685:Laser Therapy; D011817:Rabbits; D012668:Trigeminal Ganglion / Q000821:virology; D000077483:Valacyclovir; D014633:Valine / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology; D014775:Virus Activation; D017735:Virus Latency; D017201:Virus Shedding / Q000187:drug effects
D000998:Antiviral Agents; D014633:Valine; D000077483:Valacyclovir; D000212:Acyclovir