What is the recommended treatment regimen when taking antivirals (antiviral medications) for herpes?

When to Take Antivirals for Herpes

For recurrent genital herpes, start antiviral therapy immediately at the first sign of prodromal symptoms (tingling, itching, burning, pain) or within 1 day of lesion onset, using valacyclovir 500 mg twice daily for 5 days as first-line treatment. 1

Timing of Treatment Initiation

• Episodic therapy is most effective when started during the prodrome or within 1 day after onset of lesions 1
• For herpes labialis (cold sores), initiate treatment at the first sign or symptom such as tingling, itching, burning, pain, or lesion 2
• For herpes zoster (shingles), therapy should be initiated as soon as the diagnosis is made 3
• Treatment initiated more than 72 hours after symptom onset has significantly reduced effectiveness 4

Treatment Regimens by Indication

Recurrent Genital Herpes (Episodic Treatment)

First-line options:

• Valacyclovir 500 mg orally twice daily for 5 days 1
• Acyclovir 400 mg orally three times daily for 5 days 1
• Acyclovir 800 mg orally twice daily for 5 days 1
• Famciclovir 125 mg orally twice daily for 5 days 1

Alternative single-day regimen:

• Famciclovir 1000 mg twice daily for 1 day (single-day treatment) 2

Suppressive Therapy for Frequent Recurrences

Indications: Patients with ≥6 episodes per year 1, 4

Recommended regimens:

• Valacyclovir 1 g orally once daily 1
• Valacyclovir 500 mg orally once daily 1
• Acyclovir 400 mg orally twice daily 1, 5
• Famciclovir 250 mg orally twice daily 1, 2

Benefits: Suppressive therapy reduces recurrence frequency by ≥75%, reduces asymptomatic viral shedding, and is safe for up to 6 years with acyclovir and 1 year with valacyclovir 1

Herpes Labialis (Cold Sores)

• Famciclovir 1500 mg as a single dose 2
• Initiate at the first sign or symptom 2

Herpes Zoster (Shingles)

• Valacyclovir 1000 mg three times daily for 7 days 3
• Acyclovir 800 mg five times daily for 7 days 3, 5
• Famciclovir 500 mg every 8 hours for 7 days 2

HIV-Infected Patients

For recurrent orolabial or genital herpes:

• Famciclovir 500 mg twice daily for 7 days 2
• Acyclovir 400 mg orally 3-5 times daily until clinical resolution 4

Important Clinical Considerations

Common Pitfalls to Avoid

• Never use topical acyclovir - it is substantially less effective than oral therapy 1, 4, 3
• Delaying treatment beyond 72 hours significantly reduces effectiveness 4
• Failing to consider suppressive therapy in patients with frequent recurrences (≥6 per year) 4

When to Suspect Treatment Failure

• If lesions do not begin to resolve within 7-10 days of therapy, suspect acyclovir resistance 1
• For proven or suspected resistance, use foscarnet 40 mg/kg IV every 8 hours 1, 3

Severe Disease Requiring Hospitalization

• Acyclovir 5-10 mg/kg IV every 8 hours for 5-7 days or until clinical resolution 4, 3

Follow-up Recommendations

• After 1 year of suppressive therapy, consider discontinuation to reassess recurrence frequency 1, 5
• Patients with persistent symptoms beyond 5 days of treatment should be considered for extended treatment 1

Medication Administration

• Famciclovir may be taken with or without food 2
• No laboratory monitoring is needed unless the patient has significant renal impairment 4

Renal Impairment

• Dosage adjustments are required for all antivirals in patients with creatinine clearance <60 mL/min 2, 5
• For hemodialysis patients, administer an additional dose following each dialysis session 2, 5