Children aged two years and over should be given adult dosages and children below the age of two years should be given half the adult dose.

For treatment of neonatal herpes virus infections, intravenous aciclovir is recommended.

No specific data are available on the suppression of herpes simplex infections or the treatment of herpes zoster infections in immunocompetent children.

Treatment of varicella infections:

6 years and over:
 800mg four times daily
 
2 to 5 years:
 400mg four times daily
 
Under 2 years:
 200mg four times daily.
 

Treatment should continue for five days.

Dosing may be more accurately calculated as 20mg/kg bodyweight (not to exceed 800mg), four times daily.

Elderly:

In the elderly, total aciclovir body clearance declines along with creatinine clearance. Adequate hydration of elderly patients taking high oral doses of suspension should be maintained. Special attention should be given to dosage reduction in elderly patients with impaired renal function.

Dosage in renal impairment:

Caution is advised when administering aciclovir to patients with impaired renal function. Adequate hydration should be maintained.

In the management of herpes simplex infections in patients with impaired renal function, the recommended oral doses will not lead to accumulation of aciclovir above levels that have been established by intravenous infusion. However, for patients with severe renal impairment (creatinine clearance less than 10ml/minute) an adjustment of dosage to 200mg, twice daily (every 12 hours) is recommended.

In the treatment of herpes zoster and varicella infections it is recommended to adjust the dosage to 800mg of suspension twice daily (every 12 hours) for patients with severe renal impairment (creatinine clearance less than 10ml/minute) and to 800mg three times daily (six to eight hourly) for patients with moderate renal impairment (creatinine clearance in the range 10 to 25ml/minute).
4.3 Contraindications
Hypersensitivity to aciclovir, valaciclovir or any of the excipients listed in section 6.1.
4.4 Special warnings and precautions for use
Use in patients with renal impairment and in elderly patients:

Aciclovir is eliminated by renal clearance, therefore the dose must be adjusted in patients with renal impairment (See 4.2 Posology and Method of Administration). Elderly patients are likely to have reduced renal function and therefore the need for dose adjustment must be considered in this group of patients. Both elderly patients and patients with renal impairment are at increased risk of developing neurological side effects and should be closely monitored for evidence of these effects. In the reported cases, these reactions were generally reversible on discontinuation of treatment (See 4.8 Undesirable Effects). Prolonged or repeated courses of aciclovir in severely immune-compromised individuals may result in the section of virus strains with reduced sensitivity, which may not respond to continued acyclovir treatment (see section 5.1).

Hydration status: Care should be taken to maintain adequate hydration in patients receiving high oral dose regimens e.g. for the treatment of herpes zoster infection (4g daily), in order to avoid the risk of possible renal toxicity. The risk of renal impairment is increased by use with other nephrotoxic drugs.

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