What is the recommended treatment for oral herpes (cold sores)?

Treatment of Herpes Labialis (Cold Sores)

For episodic treatment of herpes labialis, initiate oral antiviral therapy at the earliest sign of symptoms (ideally during the prodrome, no later than 48 hours from lesion onset) with either single-dose famciclovir 1500 mg, valacyclovir 2 g twice daily for 1 day, or acyclovir 400 mg three times daily for 5 days 1, 2.

Treatment Algorithm

First-Line Episodic Treatment (Start at First Tingling/Prodrome)

Oral antivirals are superior to topical agents and should be your default choice 2:

• Famciclovir 1500 mg single dose - Most convenient option, reduces healing time and pain duration significantly 1, 3
• Valacyclovir 2 g twice daily for 1 day - Alternative single-day regimen with proven efficacy 1
• Acyclovir 400 mg three times daily for 3-5 days - Less convenient dosing but effective and typically less expensive 4

Critical timing caveat: Treatment must begin within 48 hours of lesion onset to achieve optimal results 2. The earlier treatment starts (ideally at prodrome), the better the outcome.

Topical Options (Second-Line or Patient Preference)

If oral therapy is contraindicated or patient prefers topical treatment:

• Acyclovir 5% + hydrocortisone 1% cream (ME-609) - Apply 5 times daily for 5 days. This combination prevented ulcerative lesions in 42% of patients versus 26% with placebo and reduced cumulative lesion area by 50% 5
• Acyclovir 5% cream alone - Less effective than the combination but still reduces lesion duration if applied early 4, 5
• Penciclovir 1% cream - Alternative topical agent 2

Important limitation: Topical agents are NOT effective for preventing recurrent episodes 2.

Chronic Suppressive Therapy

Reserve for patients with ≥6 episodes per year or severe recurrences 2:

• Acyclovir 400 mg twice daily - Demonstrated 53% fewer clinical recurrences versus placebo 1
• Valacyclovir 500 mg to 2 g daily - Effective suppression, longer time between recurrences 1, 4

Suppressive therapy significantly extends time to recurrence (118 days vs 46 days with placebo for acyclovir) 1.

Comparative Efficacy

The evidence shows oral antivirals reduce lesion duration and pain by approximately one day 6, though they typically do not abort lesions completely. Single-dose famciclovir offers the best balance of efficacy and convenience 3, with similar or superior outcomes compared to multi-day regimens while improving adherence.

Valacyclovir and famciclovir have superior oral bioavailability compared to acyclovir, requiring less frequent dosing, but are more expensive and not approved for children 2.

Special Considerations

Prevention Strategies

• Sunscreen (SPF ≥15) alone can prevent UV-triggered recurrences 4
• Consider prophylactic oral antivirals before known triggers (UV exposure, procedures)

Resistance Risk

Long-term antiviral use, especially in immunocompromised patients, predisposes to drug resistance 7. If acyclovir resistance develops, alternative agents include cidofovir or foscarnet 7.

Immunocompromised Patients

Extend treatment duration to longer than 5 days and consider lower threshold for chronic suppressive therapy 4.

Common Pitfalls to Avoid

1. Delayed treatment initiation - The 48-hour window is critical; educate patients to self-initiate therapy at first symptoms 2
2. Relying solely on topical therapy for frequent recurrences - Topicals do not prevent recurrences; switch to oral suppressive therapy 2
3. Inadequate dosing frequency - Ensure patients understand the importance of adherence to prevent resistance 1
4. Not considering suppressive therapy - Patients with frequent episodes (≥6/year) benefit significantly from daily prophylaxis 2

1, 2, 4, 5, 3, 8