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Tablet 200 mg : Each tablet contains 200 mg Acyclovir.
Tablet 400 mg : Each tablet contains 400 mg Acyclovir.
VIRDAM Tablets are indicated for the treatment of herpes simplex virus infection of the skin and mucous membranes
including initial and recurrent genital herpes.
VIRDAM Tablets are indicated for the suppression (prevention of recurrences) of recurrent herpes simplex infections in
VIRDAM Tablets are indicated for the prophylaxis of herpes simplex infections in immune-compromised patients.
VIRDAM Tablets are indicated for the treatment of herpes zoster infections. Studies have shown that treatment with
VIRDAM can reduce the incidence of post-herpetic neuralgia.
DOSAGE AND ADMINISTRATION
Treatment of herpes simplex in adults
For treatment of herpes simplex infections, 200 mg VIRDAM should be taken five times daily at approximately 4-hourly
intervals omitting the night-time dose. Treatment should continue for 5 days, but in severe initial infections may have
to be extended. In severely immune-compromised patients (e.g. after bone marrow transplantation) or in patients with
impaired absorption from the gut, the dose can be doubled to 400 mg or alternatively intravenous dosing could be
considered. Dosing should begin as early as possible after the start of an infection, for recurrent episodes this should
preferably be during the prodromal period or when lesions first appear.
Suppression of herpes simplex in adults
For suppression of herpes simplex infections in immune-competent patients, 200 mg VIRDAM should be taken four
times daily at approximately 6-hourly intervals. Many patients may be conveniently managed on a regimen of 400 mg
VIRDAM taken twice daily at approximately 12-hourly intervals, may prove effective. Some patients may experience
break-through infections on total daily doses of 800 mg VIRDAM. Therapy should be interrupted periodically at
intervals of 6-12 months to observe possible changes in the natural history of the disease.
Prophylaxis of herpes simplex in adults
For Prophylaxis of herpes simplex infections in immune-competent patients, 200 mg VIRDAM should be taken four
times daily approximately 6-hourly intervals. In severely immune-compromised patients (e.g. after marrow transplant)
or in patients with impaired absorption from the gut, the dose can be doubled to 400 mg or alternatively intravenous
dosing could be considered. The duration of prophylactic administration is determined by the duration of the period at
Treatment of herpes zoster in adults
For treatment of herpes zoster infections, 800 mg VIRDAM should be taken five times daily at approximately 4 hourly
intervals, omitting the night-time dose. Treatment should continue for 7 days. In severely immune-compromised
patients (e.g. after marrow tranplant) or in patients with impaired absorption from the gut, consideration should be
given to intravenous dosing. Dosing should begin as early as possible after the start of infection, treatment yields
better results if initiated as soon as possible after onset of the rash.
For treatment of herpes simplex infections, and for prophylaxis of herpes simplex infections in the immune-
compromised children over the age of 2 years should be given adult dosages and children bellow the age of 2 years
should be given half the adult dose. No specific data are available on the suppression of herpes simplex infections or
the treatment of herpes zoster infections in immune-competent children.
In the elderly, total Acyclovir body clearance declines in parallel with creatinine clearance. Adequate hydration of elderly
patients taking high oral doses of VIRDAM should be maintained. Special attention should be given to dosage
reduction in elderly patients with impaired renal function.
In the management of herpes simplex infections patients with impaired renal function, the recommended oral dose will
not lead to accumulation of Acyclovir above levels that have been established safe by intravenous infusion. However,
for patients with severe renal impairment (creatinine clearance less than 10 ml/minute) an adjustment of dosage to
200 mg twice daily at approximately 12 hourly intervals is recommended. In the treatment of herpes zoster infections,
it is recommended to adjust the dosage to 800 mg twice daily approximately 12-hourly intervals for patients with server
renal impairment and to 800 mg three or four times daily at intervals of approximately 6-8 hourly for patients with
moderate renal impairment (creatinine clearance in the range 10-25 ml/minute).
VIRDAM Tablets are contra indicated in patients known to be hypersensitive to Acyclovir.
Mutagenicity, Carcinogenicity, Effects on fertility
The result of a wide range of mutagenicity tests in vitro and in indicate that Acyclovir does not pose a genetic rist to man.
Acyclovir was not found to be carcinogenicity in long-term studies in the rat and the mouse.
Largely reversible adverse effects on spermatogenesis in association with overall toxicity in rats and dogs have been reported
only at doses of Acyclovir greatly excess of those employed therapeutically.
Two-generation studies in mice did not reveal any effect of orally administered Acyclovir on fertility. There is no experience of
the effect of VIRDAM Tablets on human female fertility, VIRDAM Tablets have been to have no decline effect upon
spermcount, morphology or mortility in man.
Probenecid increase the mean half-life and area under plasma concentration curve of systemically administered Acyclovir.
Other drugs affecting renal physiology could potentially influence the pharmacokinetics of Acyclovir. However, clinical
experience has not identified other drug interactions with Acyclovir.
SIDE AND ADVERSE EFFECTS
Skin rashes have been reported in a few patients receiving VIRDAM Tablets, the rashes have resolved on withdrawal of the
drug. Gastro intestinal effects, including nausea, vomiting, diarrhea and abdominal pains, have been reported some patients
receiving VIRDAM Tablets. In double blind, placebo-controlled trials, the incidence of gastrointestinal events has not been to
differ between placebo and Acyclovir recipients.
Use in pregnancy and lactation
Systematic administration of Acyclovir in internationally accepted standard tests did not produce embryotoxic or teratongenic
effects in rabbits, rats or mice. In a non-standard test in rats, fetal abnormalities were observed but only following such high
subcutaneous doses that maternal toxicity was produced. The clinical of these findings is uncertain. Experience in humans is
limited, so the use of VIRDAM Tablets should considered only when the potential benefits benefit outweigh the possibility of
unknown risk. Limited human data be show that the drug does pass into breast milk.
TOXICITY AND TREATMENT OF OVERDOSAGE
Acyclovir is only partly absorbed in the gastro intestinal tract. It is unlikely that serious toxic effects would occur if a dose of up
5 g were taken on a single occasion. No data are available in the consequences of the ingestion of higher doses. Single
intravenous does of up to 80 mg/kg body weight have been inadvertently administered without adverse effects. Ingestion of
doses of Acyclovir in excess of 5 g warrants close observation of the patient Acyclovir is dialysable.
Mode of action
Acylovir is an anti virus agent which is highly active in vitro against herpes simplex virus (HSV) types I and II and
varicella zoster virus. Toxicity to mammalian host cells is low. Acyclovir is phosphorylated after entry into herpes-
infected cells to the active compound Acyclovir triphosphate. The first step in this process is dependent on the presence
of the viral-coded thymidine kinase. Acyclovir triphosphate acts as an inhibitor of and substrate for the herpes-specified
DNA polymerase preventing further viral DNA synthesis without affecting normal cellular processes.
Acyclovir is only partly absorbed from the gut. Mean steady state plasma concentrations (C max) following doses of
200 mg administered 4-hoursly were 0.68 mcg/ml and the equivalent trough plasma levels (C min) were 0.36 ug/ml.
Corresponding steady state plasma concentration following doses of 800 mg administered 4-hourly were 1.56 ug/ml
and 0.79 mcg/ml respectively. From studies with intravenous Acyclovir, the terminal plasma half-life has been
determined as about 29 hours. Most of the drug is excreted unchanged by the kidney. Renal clearance of Acyclovir is
substantially greater than creatinine clearance that tubular secretion in addition to glomerular filtration contributes to
the renal elimination of the drug.
The only significant metabolite of Acyclovir is 9-carboxymethyl-guanine which accounts for 10-15 % of the total amount
of drug recovered in the urine. In patients which chronic renal failure, the mean terminal half-life was found to be 19.5
hours. The mean Acyclovir levels dropped approximately 60 % during dialysis. In the elderly, total body clearance falls
with increasing age associated with decreases in creatinine clearance, although there is a little change in terminal
Tablet 200 mg. Box of 5x10’s Reg.No. DKL9421008110A1.
Tablet 400 mg. Box of 5x6’s . Reg.No. DKL9521008110B1
On medical prescription only.