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Condition guide · /antiviral/
Antiviral treatments
Reviewed by Dr. Arjun Mehta, PharmD — Head Pharmacist. Updated May 2025.
4
Main antiviral classes
Hours
Time-critical for shingles
Daily
Suppression for HSV
Rx
Medicines in this guide
From $26
From $34
From $42
About this condition
Antiviral medicines target specific stages of viral replication. Unlike antibiotics, antivirals are usually narrow-spectrum — a drug effective against herpes will not work on influenza, and vice versa. Timing is critical: most antivirals work best when started within hours to days of symptom onset.
Common antiviral classes you will see on this page include nucleoside analogues for herpes viruses (acyclovir, valacyclovir), neuraminidase inhibitors for influenza (oseltamivir), and antiretrovirals for HIV. Hepatitis B and C have their own direct-acting agents that have transformed treatment.
Treatment options
Acyclovir
First-line for herpes simplex (cold sores, genital herpes) and varicella zoster (shingles). Inexpensive and well-tolerated.
Valacyclovir
Oseltamivir
Influenza A and B. Most effective if started within 48 hours of symptom onset.
Antiretrovirals
Lifelong combination therapy for HIV. Modern regimens have transformed HIV into a manageable chronic condition.
Common questions
Are antivirals available without a prescription?
No. Almost all antiviral medicines are prescription-only and should be started under medical guidance.
Why are antivirals time-critical?
Most viruses replicate quickly. Once viral load peaks, drugs become less effective. For shingles and influenza in particular, every hour of delay matters.
Can I stop antiviral suppression for HSV?
Daily suppression reduces outbreaks and transmission. Stopping is reasonable when outbreaks are infrequent, but speak to your prescriber first.
Dr. Arjun Mehta, PharmD · Head Pharmacist
/our-pharmacists/arjun-mehta/ — Reviewed May 2025
This guide is reviewed every 12 months or sooner when clinical guidance changes. If you have a specific medical question, call our pharmacist team — we answer the phone, not a bot.
