Valaciclovir – Advanced antiviral for herpes infections with improved absorption.
Get expert medical advice and same-day prescriptions from qualified UK doctors through our secure online consultation platform.
- Professional online consultation and prescription
- Same-day service when clinically appropriate
- Secure delivery to your chosen pharmacy
Secure Telehealth Platform Trusted by Over 150,000 Patients
What is Valaciclovir?
Valaciclovir is an advanced antiviral medication that offers improved convenience and effectiveness compared to aciclovir for treating herpes virus infections. Its better absorption allows for less frequent dosing and often superior clinical outcomes.
Book an online consultation if you’re experiencing symptoms of viral infections such as cold sores, genital herpes, or shingles, or if you need suppressive therapy for recurrent herpes infections. Our GPs can assess your symptoms and determine if Valaciclovir is the appropriate antiviral treatment for your specific condition.
What is Valaciclovir used for?
- Cold sores (herpes simplex)
- Genital herpes infections
- Shingles (herpes zoster)
- Prevention of recurrent herpes infections
- Chickenpox (in immunocompromised patients)
- Cytomegalovirus prevention (in transplant patients)
- Herpes suppression therapy
How does Valaciclovir work?
A prodrug of aciclovir that's converted to aciclovir in the body, providing better oral absorption and higher blood levels than aciclovir itself, allowing for less frequent dosing.
Dosage and Administration
Adults
Cold sores: 2g twice daily for 1 day. Genital herpes: 500mg twice daily for 3-5 days. Shingles: 1g three times daily for 7 days.
Children
Dose calculated based on weight and indication—specialist supervision usually required.
Important Notes
- Start treatment as early as possible when symptoms begin.
- Take with plenty of water to prevent kidney problems.
- Can be taken with or without food.
- Complete the full course even if symptoms improve.
Side Effects
Common Side Effects
- Headache
- Nausea and vomiting
- Dizziness
- Abdominal pain
- Fatigue
- Skin rash
Serious Side Effects
Seek immediate medical attention if you experience:
- Kidney problems (especially with high doses)
- Severe allergic reactions
- Confusion or hallucinations (rare)
- Blood disorders (very rare)
- Severe skin reactions
Important Warnings
- Drink plenty of fluids to prevent kidney damage, especially with high doses.
- Tell your GP if you have kidney problems—dose adjustment needed.
- Start treatment as soon as possible after symptom onset for best effectiveness.
- Not a cure—helps control symptoms and reduce duration of outbreaks.
- Does not prevent transmission of herpes to others during treatment.
Drug Interactions
Tell your GP if you're taking any of the following medications:
- Probenecid—may increase valaciclovir levels and kidney toxicity risk.
- Mycophenolate—may increase levels of both medications.
- Nephrotoxic drugs—increased risk of kidney damage.
- Generally fewer interactions than many other antiviral medications.
Frequently Asked Questions
How is Valaciclovir different from Aciclovir?
Valaciclovir is better absorbed when taken by mouth, achieving higher blood levels with less frequent dosing. This makes it more convenient and often more effective.
How quickly does Valaciclovir work for cold sores?
If started within 24 hours of symptom onset, it can reduce duration by 1-2 days and lessen severity. The 1-day course (2g twice daily) is very convenient.
Can I use Valaciclovir to prevent herpes outbreaks?
Yes, daily suppressive therapy (500mg-1g daily) can significantly reduce the frequency of recurrent genital herpes outbreaks and transmission risk.
Is Valaciclovir safe during pregnancy?
It's generally considered safe in pregnancy when benefits outweigh risks, but should only be used under medical supervision with careful monitoring.
Medically Reviewed by: Mohammed Hassan - Independent Prescriber
Last Updated: 2025-01-14