Zovirax

Aciclovir

Listed in Dosage.

Oral Adult Treatment of Herpes simplex 200 mg 5 times daily at 4-hrly intervals for 5 days. Omit night dose. Suppression of Herpes simplex infection in immunocompetent patient & prophylaxis of Herpes simplex infections in immunocompromised patient 200 mg qds at approx 6-hrly interval. For suppression of Herpes simplex infection in immunocompetent patient Many patients may be conveniently managed on a regimen of 400 mg bd at approx 12-hrly interval. Treatment of varicella (chickenpox) & Herpes zoster (shingles) 800 mg 5 times daily at 4-hrly intervals for 7 days. Omit night dose. Childn Treatment of Herpes simplex & prophylaxis of Herpes simplex in immunocompromised ≥2 yr Adult dose, <2 yr ½ adult dose. For treatment of neonatal herpes virus infections, IV aciclovir is recommended. Treatment of varicella infection ≥6 yr 800 mg qds, 2-5 yr 400 mg qds, <2 yr 200 mg qds. Dose may be more accurately calculated as 20 mg/kg body wt (Max: 800 mg) qds. Continue treatment for 5 days. IV infusion Adult Herpes simplex (except Herpes encephalitis) or Varicella zoster infections 5 mg/kg body wt 8 hrly. Immunocompromised patient w/ Varicella zoster infections or patient w/ Herpes encephalitis 10 mg/kg body wt 8 hrly. In obese patients dosed w/ IV aciclovir based on their actual body wt, higher plasma conc may be obtained. Consideration should therefore be given to dosage reduction in obese patients & especially in those w/ renal impairment or the elderly. Childn ≥3 mth Herpes simplex (except Herpes encephalitis) or Varicella zoster infections 250 mg/m² of BSA 8 hrly if renal function is not impaired. Immunocompromised childn w/ Varicella zoster infections or childn w/ Herpes encephalitis 500 mg/m² of BSA 8 hrly if renal function is not impaired. Neonates & infant up to 3 mth Known or suspected neonatal herpes 20 mg/kg IV every 8 hr for 21 days for disseminated & CNS disease, or for 14 days for disease limited to the skin & mucous membranes. Infants & childn w/ impaired renal function require an appropriately modified dose, according to the degree of impairment.

May be taken with or without food.

Hypersensitivity to valaciclovir or aciclovir or to any of the excipients.

In patients receiving Zovirax IV at higher doses, specific care regarding renal function should be taken, particularly when patients are dehydrated or have any renal impairment. IV doses should be given by infusion over 1 hr. Care is required if administering IV aciclovir w/ other nephrotoxic drugs. Patients on a controlled Na diet should consider the Na content of the IV product. Maintain adequate hydration in patient on high oral or IV doses. Pregnancy & lactation. Elderly. Renal impairment. Prolonged or repeated courses of aciclovir in severely immune-compromised individuals. Oral susp contains methyl- & propyl-parahydroxybenzoate which may cause allergic reactions. It also contains sorbitol, hence do not take in patients w/ rare hereditary problems of fructose intolerance.

Nausea, vomiting, diarrhoea, abdominal pain; pruritus, urticaria, rashes (including photosensitivity). Headache, dizziness, increase in bilirubin & liver enzymes, blood urea & creatinine, fatigue, fever. Phlebitis (IV infusion).

Increased plasma conc w/ probenecid & cimetidine due to competitive inhibition of renal tubular secretion. Concomitant therapy w/ aciclovir increases AUC of totally administered theophylline. Increased plasma AUC w/ mycophenolate mofetil. Caution if IV infusion is co-administered w/ drugs that affect renal physiology eg, cyclosporin, tacrolimus. Risk of lithium toxicity if administered concurrently w/ high dose aciclovir IV, hence the lithium serum conc should be closely monitored.

Antivirals

J05AB01 - aciclovir ; Belongs to the class of nucleosides and nucleotides excluding reverse transcriptase inhibitors. Used in the systemic treatment of viral infections.

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