Antiviral Medications: Prescription Treatments for Herpes Simplex (HSV), Shingles (VZV), Influenza & Parkinson’s Dyskinesia

Antiviral medications work by targeting specific steps in viral replication cycles. Unlike antibiotics, which kill or inhibit bacteria, antivirals most commonly suppress viral replication — they do not permanently eliminate latent viruses such as herpes simplex or varicella-zoster, which remain dormant in nerve ganglia for life. However, antivirals can dramatically shorten the duration of active outbreaks, reduce severity, decrease viral shedding and transmission risk, and with suppressive therapy, reduce recurrence frequency. All antiviral medications covered here require a prescription.

How Are Antivirals Classified?

The antivirals featured on this site target two very different indications:

• Nucleoside analogue antiherpetics (acyclovir, valacyclovir, famciclovir) — interfere with viral DNA polymerase; active against HSV-1, HSV-2, VZV (shingles and chickenpox), and EBV
• Adamantane antivirals (amantadine) — originally targeted influenza A M2 ion channel; now primarily used for its dopaminergic effects in Parkinson’s disease

Antiviral Medications at Lucas Clinic

• Amantadine 100 mg Tablets — prescription antiviral originally developed for influenza A (now high resistance); primarily prescribed for Parkinson’s disease dyskinesia and as an antiviral adjunct
• Valtrex (Valacyclovir) 500 mg & 1 g Tablets — prescription prodrug of acyclovir; for herpes simplex (HSV-1/HSV-2), shingles (VZV), cold sore treatment and suppression; better oral bioavailability than acyclovir

Are Antivirals Available Over the Counter?

No oral antivirals for herpes or influenza are currently available without a prescription in the US, UK, or EU. Topical OTC options exist for cold sores — including docosanol (Abreva) cream — but oral antivirals with more reliable efficacy require a prescription. Some telehealth platforms can provide online prescriptions for valacyclovir for HSV after consultation.