Virunil-200

Acyclovir is an antiviral medicine that is highly active in laboratory studies against Herpes simplex virus (HSV) types I and II and Varicella zoster virus, while remaining low in toxicity to mammalian cells. After entering a herpes-infected cell, acyclovir is phosphorylated into the active compound acyclovir triphosphate. The first step of this process depends on the presence of the viral-coded thymidine kinase. Acyclovir triphosphate then acts as both an inhibitor of and a substrate for the herpes-specified DNA polymerase, blocking further viral DNA synthesis without disrupting normal cellular processes.

Pregnancy category B. No adequate, well-controlled studies have looked at Acyclovir's effects in pregnant women. It is also not known whether the topical form of this medicine passes into breast milk.

Pediatric use: For children aged 1 to 12 years, the dose of Acyclovir IV injection should be worked out from body surface area. Children in this age group with Herpes simplex infections (except Herpes simplex encephalitis) or Varicella zoster infections should get Acyclovir IV Infusion at 250 mg/m2 (equivalent to 5 mg/kg in adults). Immunocompromised children of the same age with Varicella zoster virus infection, or with Herpes simplex encephalitis, should get Acyclovir IV Infusion at 500 mg/m2 (equivalent to 10 mg/kg in adults). If a child has impaired renal function, the dose needs to be changed to suit the degree of impairment.

Geriatric use: No data are available on this age group. But creatinine clearance is often low in the elderly, so special attention should be given to reducing the dose.

In patients with renal impairment: Acyclovir should be given with caution because the drug is excreted through the kidneys. These dose changes are suggested:

CrCl 25 to 50 ml/min: 5 or 10 mg/kg every 12 hours.

CrCl 10 to 25 ml/min: 5 or 10 mg/kg every 24 hours.

CrCl 0 to 10 ml/min: 2.5 or 5 mg/kg every 24 hours and after dialysis.

Too much intravenous Acyclovir has led to a rise in serum creatinine and blood urea nitrogen, and after that to renal failure. Neurological effects have also been reported with overdose, including confusion, hallucinations, agitation, seizures and coma. Patients need adequate hydration, because it lowers the chance of crystals forming in the urine. Hemodialysis removes Acyclovir from the blood to a significant degree, so it may be considered as an option when managing an Acyclovir overdose.

Keep Acyclovir in a cool, dry place, away from light, and out of reach of children. Don't touch the tip of the tube, because this may contaminate the product. Once the tube has been open for one month, don't use the medicine in it any more.