Valacyclovir: Uses, Dosage, Side Effects & Brands | MedexInfo

Valacyclovir

Generic NameValacyclovir Hydrochloride

Therapeutic ClassAntiviral (Nucleoside analogue)

Max / 24h3 g

Common Dose500 mg–1 g orally q12h depending on indication

PregnancyUse if clearly needed (Category B)

Indications ▼

Treatment of herpes simplex virus infections (oral and genital)

Management of herpes zoster (shingles)

Prevention of recurrent genital herpes

Mechanism & Pharmacokinetics ▼

Mechanism: Prodrug converted to acyclovir in the liver; inhibits viral DNA polymerase, preventing viral DNA replication.

Pharmacokinetics: Oral absorption ~55%; peak plasma levels in 1–2 hours; renal excretion of unchanged drug; half-life 2.5–3.5 hours in healthy adults.

Dosage & Administration ▼

Condition	Recommended Dose	Frequency
Genital herpes, initial episode	1 g	Orally every 12 hours for 10 days
Genital herpes, recurrent	500 mg	Orally every 12 hours for 3 days
Herpes zoster (shingles)	1 g	Orally every 8 hours for 7 days
Suppression of recurrent genital herpes	500 mg–1 g	Orally once or twice daily

Note: Adjust dose in renal impairment; maintain adequate hydration to prevent crystalluria.

Side Effects ▼

Headache, dizziness

Nausea, vomiting

Abdominal pain

Rare: Nephrotoxicity, thrombotic microangiopathy, confusion, hallucinations

Contraindications ▼

Hypersensitivity to valacyclovir or acyclovir

Use with caution in renal impairment

Drug Interaction ▼

Other nephrotoxic drugs: increased risk of renal toxicity

Probenecid: may increase plasma concentration of valacyclovir

Pregnancy & Lactation ▼

Category B: Use only if clearly needed

Excretion in breast milk is minimal; caution advised

Clinical / Research Summary ▼

Therapeutic Role: Prodrug antiviral with better oral bioavailability than acyclovir; effective for treatment and suppression of herpes virus infections.

Clinical Effectiveness: Reduces duration and severity of herpes outbreaks; effective in prevention of recurrent genital herpes.

Safety Profile: Generally well tolerated; renal function monitoring advised in patients with kidney disease.

Current Research: Studies focus on optimal dosing for prophylaxis, combination therapy in immunocompromised patients, and long-term safety.

Patient Counseling Points ▼

Take with plenty of fluids to reduce risk of kidney problems

Adhere strictly to dosing schedule

Report signs of kidney issues, confusion, or severe rash

Not a cure; reduces severity and frequency of outbreaks

Storage & Handling ▼

Store at 20–25°C, protect from light

Keep out of reach of children

Brand Names (Bangladesh & Global) ▼