Studies comparing the antiviral drugs idoxuridine, adenine arabinoside, and 15%, 10%, and 3% hypoxanthine arabinoside reveal that the first three drugs all have equal therapeutic efficacy in treatment of established herpes simplex keratoconjunctivitis. The idoxuridine and all hypoxanthine arabinoside formulations are equally effective in antiviral prophylaxis. Hypoxanthine arabinoside is the highly soluble natural metabolite of adenine arabinoside and has the advantages over idoxuridine of intraocular penetration and lack of tissue toxicity.
Pavan-Langston D, Langston RHS, Geary PA. Prophylaxis and Therapy of Experimental Ocular Herpes SimplexComparison of Idoxuridine, Adenine Arabinoside, and Hypoxanthine Arabinoside. Arch Ophthalmol. 1974;92(5):417–421. doi:10.1001/archopht.1974.01010010429012