Acyclovir USP 200 mg/400 mg per
200 mg: Light blue, hexagonal and
convex tablet, 10mm diameter with score-line and "DHA" logo.
400 mg: Light pink, round and convex tablet, 12mm diameter with cross
score-line and without logo.
Acyclovir is active against
herpes simplex virus types 1 and 2 (HSV-1 & 2) and against varicella zoster
virus. This activity is due to intracellular conversion of acyclovir by
viral thymidine kinase to monophosphate with subsequent conversion to
diphosphate and to the active tiphosphate. This active trlphosphate is a
potent inhibitor of HSV-1 & 2 DNA polymerase enzyme and
a DNA chain terminator. This process is highly selective for infected cells.
Acyclovir is only partially
absorbed from the gut. Mean steady state peak plasma concentrations
following doses of 200mg administered 4 hourly were 3.1Ámol and equivalent
trough plasma levels were 1.8Ámol. Corresponding levels following doses of
400 and 800mg administered 4-hourly were 5.3Ámol and 8Ámol, respectively,
and equivalent levels were 2.7Ámol and 4Ámol.
Plasma Acyclovir levels dropped approximately 60% during dialysis.
Herpes simplex infections of the
skin and mucous membranes. Treatment of herpes zoster (shingles) and
varicella (chicken-pox) infections.
Adults: Herpes simplex: Treatment: 200 mg, 5 times daily for 5 days.
Treatment may be extended in severe cases. Prophylaxis: 200 mg, 4 times
daily. Herpes zoster and varicella: Treatment: 800 mg, 5 times daily for 7
days. Doses to be taken with or without food.
Suppression of herpes simplex: 200 mg 4 times daily at approximately
6-hourly intervals or 400 mg twice daily at approximately 12-hourly,
intervals. Dosage may be titrated down to 200 mg twice or 3 times daily.
be interrupted periodically at intervals of 6-12 months in order to observe
possible changes in natural history of the disease.
Prophylaxis of herpes
simplex infections: 200 mg 4 times daily at approximately 6-hourly
intervals. Dosage may be doubled in severely immune-compromised patients
(e.g. after marrow transplant) or in patients with impaired absorption from
Treatment of varicella and herpes zoster infections: 800 mg 5 times
daily at approximately 4-hourly intervals, omitting the night-time dose.
Treatment should continue for 7 days.
Children: For treatment of herpes simplex infections and for
prophylaxis of herpes simplex infections in the immune compromised, children
above 2 years should be given adult dosages and children below 2 years
should be given half of the adult dose.
For treatment of varicella
infections: Children above 6 years: 800 mg 4
times daily; 2-6 years: 400 mg 4 times daily; Below 2 years: 200 mg 4 times
daily; Dosing may be calculated as 20 mg
Zoral/kg body weight (not to exceed 800 mg) 4 times daily. Treatment should
continue for 5 days.
Elderly: Adequate hydration of elderly patients taking high oral
doses of Zoral should be maintained.
For patients with renal impairment the following dosing regimen should be
Creatinine clearance (mL/min)
Less than 10
200 mg twice daily at approximately 12-hourly intervals for
herpes simplex infections.
800 mg twice daily at approximately
12-hourly intervals for varicella and herpes zoster infections.
800 mg 3 or 4 times daily at approximately 6-8 hours
for varicella and herpes zoster infections.
Occasional adverse effects
include increased values for liver enzymes, haematological and
encephalopathic change. There have been reports of skin rashes and
gastro-intestinal effects with acyclovir given by month, but it is usually
Acyclovir should be administered
with caution to patients with renal impairment and doses should be adjusted
according to creatinine clearance.
USE IN PREGNANCY
Should be used only if potential
benefits outweigh the risks.
Contraindicated in patients known
to be hypersensitive to Acyclovir.
Increased mean half-line and
plasma concentration with probanecid. Other drugs affecting renal physiology
could influence the pharmacokinetics of Acyclovir.
Blister pack (strip of 10's). 200
mg: 10 x 10's and 10 x 10 x 10's, 400 mg: 7 x 10's and 10 x 10 x 10's.
Keep in a cool, dry place. Below