Vidarabine Monohydrate is primarily used as an antiviral medication, particularly effective against herpes simplex virus and varicella-zoster virus. It is applied in the treatment of herpes simplex encephalitis, a severe infection of the brain caused by the herpes simplex virus. Additionally, it is used to manage herpes zoster (shingles) in immunocompromised patients, helping to reduce the severity and duration of the infection. In ophthalmology, Vidarabine Monohydrate is formulated into eye ointments to treat herpes simplex keratitis, an infection of the eye caused by the herpes simplex virus, aiding in the prevention of corneal damage and vision loss. Its mechanism involves inhibiting viral DNA synthesis, thereby controlling the spread of the virus within the host.

Vidarabine Monohydrate is often administered via injection for patients with severe symptoms or those unable to take oral medication. It requires close medical supervision due to potential severe side effects, such as leukopenia or liver inflammation.

Ongoing research is exploring its application in treating other viral infections, though these uses remain in experimental stages to confirm efficacy and safety.