📋 Indications & Clinical Dosage
*Herpes zoster infection, treatment:*
Adult: 500 mg 3 times a day for 7 days, alternatively 750 mg 1-2 times a day for 7 days. In immune-compromised patients: Adult: 500 mg 3 times a day for 10 days, continue for 2 days after crusting of lesions.
*Genital herpes, suppression:*
Adult: 250 mg twice daily, therapy to be interrupted every 6-12 months to reassess recurrence frequency; consider restarting after two or more recurrences. In immune-compromised or HIV-positive patients: Adult: 500 mg twice daily, therapy to be interrupted every 6-12 months to reassess recurrence frequency; consider restarting after two or more recurrences.
*Genital herpes infection, treatment of first episode:*
Adult: 250 mg 3 times a day for 5 days or longer if new lesions appear during treatment or if healing incomplete. In immunocompromised or HIV-positive patients: Adult: 500 mg twice daily for 10 days.
*Genital herpes infection, treatment of recurrent infection:*
Adult: 125 mg twice daily for 5 days, alternatively 1g twice daily for 1 day. In immune-compromised or HIV-positive patients: Adult: 500 mg twice daily for 5-10 days.
*Herpes simplex infection (non-genital), treatment in immunocompromised patients:*
Adult: 500 mg twice daily for 7 days.
⚠️ Precautions & Warnings
Real impairment, severe hepatic impairment.
🔄 Drug Interactions
Cimetidine, digoxin, probenecid, theophylline.
⚠️ Adverse Reactions / Side Effects
Headache, nausea, vomiting, confusion, dizziness, drowsiness, hallucinations, jaundice, rash, Stevens-Johnson syndrome, thrombocytopenia, constipation, abdominal pain, diarrhoea, fatigue, fever, pruritus, sweating
🤰 Pregnancy & Lactation Safety
Pregnancy Risk:
Avoid, use only when no safer alternative exists for a serious problem.
Lactation / Breastfeeding:
Contraindicated
📚 Official Regulatory & Clinical References
- Drug Regulatory Authority of Pakistan (DRAP): Drug Registration, S.R.O. Price Gazettes & National Essential Medicines List (NEML).
- World Health Organization (WHO): Collaborating Centre for Drug Statistics Methodology (ATC/DDD Index).
- Formulary Standards: British National Formulary (BNF) & Pakistan National Formulary (PNF) guidelines.