Is Valtrex (valacyclovir) effective for treating headaches?

Valacyclovir (Valtrex) is NOT Indicated or Effective for Treating Headaches

Valacyclovir is not recommended for treating headaches and may actually cause headache as a side effect. 1

Understanding Valacyclovir's Indications

Valacyclovir (Valtrex) is an antiviral medication specifically approved for:

1. Treatment of herpes labialis (cold sores)
2. Management of herpes zoster (shingles)
3. Treatment of herpes simplex infections
4. Suppressive therapy for recurrent herpes infections

Mechanism of Action

Valacyclovir is a prodrug of acyclovir that works by inhibiting viral DNA synthesis in herpes viruses. It has no known mechanism for treating primary headache disorders such as migraine or tension headaches.

Evidence Against Using Valacyclovir for Headaches

Clinical studies evaluating valacyclovir for herpes labialis have actually shown that headache is one of the most common adverse effects of the medication:

• In head-to-head trials of valacyclovir versus placebo for herpes labialis, headache was more common with valacyclovir than with placebo 1
• Other common side effects include nausea, diarrhea, dyspepsia, dry mouth and flatulence 1

Appropriate Treatments for Headaches

For patients seeking treatment for headaches, evidence-based options include:

For Migraine:

• First-line acute treatments:
  • Triptans (sumatriptan, rizatriptan)
  • NSAIDs
  • Combination medications (aspirin-acetaminophen-caffeine) 2

For Tension Headaches:

• NSAIDs
• Acetaminophen
• Combination analgesics

Clinical Decision Making Algorithm

1. Determine headache type:

   • Migraine features: unilateral, pulsating, moderate/severe intensity, aggravated by activity, associated with nausea/vomiting or photophobia/phonophobia
   • Tension-type features: bilateral, pressing/tightening, mild/moderate intensity, not aggravated by activity

2. Rule out secondary causes requiring specific treatment:

   • New onset severe headache
   • Headache with fever, neck stiffness (consider meningitis/encephalitis)
   • Focal neurological deficits
   • Immunocompromised state

3. For primary headache disorders:

   • Select appropriate evidence-based treatment
   • Monitor response over 2-3 episodes before changing therapy 2

Important Caveat

If a patient has herpes-related headache (as part of herpes encephalitis), valacyclovir is not the treatment of choice. Intravenous acyclovir is recommended for herpes simplex encephalitis 1, not oral valacyclovir.

Conclusion

Valacyclovir has no established role in treating primary headache disorders. Using it for this purpose would be off-label and not supported by clinical evidence. In fact, headache is a recognized side effect of valacyclovir therapy, making it counterproductive for headache treatment.