Novirax-400 Tablet

Antiviral for herpes virus infections:

• Cold sores (herpes labialis) and genital herpes — first episode, recurrences, and suppression
• Shingles (herpes zoster)
• Chickenpox (varicella), especially in adolescents, adults and high-risk patients
• Herpes eye infection (eye ointment)
• Serious infections: herpes encephalitis, neonatal herpes, infections in immunocompromised people (IV)

Adults:

• Genital herpes (first episode): 400 mg three times daily or 200 mg five times daily for 5–10 days; recurrence 400 mg three times daily for 5 days (or 800 mg twice daily); suppression 400 mg twice daily.
• Shingles: 800 mg five times daily for 7 days (start within 72 hours of rash).
• Chickenpox: 800 mg five times daily for 5–7 days (start within 24 hours).
• Cream 5%: apply five times daily for 5–10 days, starting at the first tingle.
• Eye ointment 3%: five times daily, continuing 3 days after healing.

Children:

• Chickenpox (2 years and over): 20 mg/kg (max 800 mg) four times daily for 5 days.
• Herpes simplex (2 years and over): adult dose; under 2 years: half the adult dose.
• IV: 5–20 mg/kg every 8 hours depending on age and condition (hospital).
• Drink plenty of fluids. Kidney impairment: reduce dose.

• Allergy to acyclovir or valacyclovir

Common: nausea, vomiting, diarrhoea, headache, dizziness, rash, sun sensitivity; cream: stinging, dryness; eye ointment: mild stinging.

Rare but serious: kidney injury (crystals, especially with IV and dehydration), neurological effects — confusion, hallucinations, tremor, seizures (especially elderly or with kidney impairment), severe allergic reactions, low blood counts, liver inflammation.

• Keep well hydrated, especially with high doses or IV use.
• Elderly and kidney impairment: lower doses to avoid nerve toxicity.
• Genital herpes: avoid sex during outbreaks; the drug does not prevent transmission completely.
• Treatment works best when started early.

Can be used in pregnancy when needed (widely used, no increased birth-defect risk). Compatible with breastfeeding.

• Probenecid, cimetidine (raise levels)
• Mycophenolate (both levels may rise)
• Other kidney-toxic drugs: aminoglycosides, ciclosporin, tacrolimus, NSAIDs (monitor kidneys)
• Theophylline (levels may rise)
• Lithium (monitor levels with high IV doses)

Confusion, agitation, seizures, kidney failure. Supportive care; haemodialysis removes it.

Store below 30°C. IV solution: do not refrigerate after dilution.