What is the medication and dosing (SIG) for recurrent herpes simplex labialis (cold sore) outbreaks?

Medication and Dosing for Cold Sore Flares

For recurrent herpes labialis (cold sores), the recommended treatment is famciclovir 1500 mg as a single dose at the first sign or symptom of a cold sore (e.g., tingling, itching, burning, pain, or lesion). 1

First-Line Treatment Options

Famciclovir

• Dosing: 1500 mg as a single dose
• Timing: Initiate at the first sign or symptom (prodromal phase)
• Administration: Can be taken with or without food 1

Renal Dosage Adjustments for Famciclovir

Creatinine Clearance (mL/min)	Recommended Dose
≥60	1500 mg single dose
40-59	750 mg single dose
20-39	500 mg single dose
<20	250 mg single dose
Hemodialysis	250 mg single dose following dialysis [1]

Alternative Treatment Options

Valacyclovir

• For patients with frequent recurrences (≥6 episodes per year), suppressive therapy may be considered:
  • Dosing: 500 mg once daily for patients with <10 recurrences per year
  • Dosing: 1000 mg once daily for patients with ≥10 recurrences per year 2

Renal Dosage Adjustments for Valacyclovir

Creatinine Clearance (mL/min)	Suppressive Therapy Dosing
≥50 (normal)	No adjustment needed
30-49	No adjustment needed
10-29	500 mg every 24 hours
<10	500 mg every 24 hours [2]

Treatment Approach Algorithm

1. Episodic Treatment: For patients with infrequent outbreaks

   • Famciclovir 1500 mg as a single dose at first sign of outbreak 1
   • Ensure patient understands the importance of early treatment to reduce pain, speed healing, and shorten viral shedding duration 2

2. Suppressive Therapy: For patients with frequent recurrences (≥6 episodes per year)

   • Valacyclovir 500 mg daily (for <10 recurrences/year)
   • Valacyclovir 1000 mg daily (for ≥10 recurrences/year) 2
   • Suppressive therapy can reduce recurrence frequency by ≥75% 2

Important Clinical Considerations

• Timing is critical: Treatment efficacy is maximized when started during the prodromal phase or within hours of lesion appearance
• Topical therapy alone is substantially less effective than systemic therapy 2
• Monitor for complications such as secondary bacterial infection
• Assess treatment response within 72 hours and follow up until complete resolution of lesions 2
• Patient education should include:
  • Recognition of prodromal symptoms
  • Importance of early treatment initiation
  • Natural history of disease and potential for recurrent episodes
  • Risk of viral transmission
  • Need to abstain from contact when lesions or prodromal symptoms are present 2

Special Populations

Immunocompromised Patients

• For HIV-infected patients with recurrent orolabial herpes:
  • Famciclovir 500 mg twice daily for 7 days 1
• More aggressive therapy may be required for immunocompromised children 2

Pitfalls to Avoid

• Delaying treatment beyond the prodromal phase significantly reduces efficacy
• Inadequate dosing adjustments in patients with renal impairment
• Failing to monitor renal function before starting therapy in at-risk patients
• Inadequate hydration during treatment, which can increase risk of adverse effects 2