Combined chemotherapy of cutaneous herpes simplex infection of the guinea pig.

Cutaneous infection of guinea pigs with HSV1 was topically treated from 2 to 6 days post infection with 7 antiherpetic substances. Phosphonoformic acid and acyclovir were found to be highly effective; trifluorothymidine, thymine arabinoside, ethyldeoxyuridine, and adenine arabinoside monophosphate all had some therapeutic effect in decreasing order, whereas iododeoxyuridine was ineffective. The efficacy of treatment was evaluated from cutaneous lesion scores by the Wilcoxon rank test. The substances were combined in marginally effective concentrations. From the 21 combinations, acyclovir + phosphonoformic acid, acyclovir + thymine arabinoside, and phosphonoformic acid + thymine arabinoside suggested a synergistic interaction, which appeared significant for acyclovir + phosphonoformic acid.