aciclovir sodium: clinical use

Prescribing considerations

• Assess renal function, hydration status, age and concurrent nephrotoxic treatment before and during intravenous therapy.
• Avoid rapid or bolus injection because high peak concentrations can promote renal precipitation and injury.
• Consider altered exposure in obesity rather than relying uncritically on actual body weight.
• Repeated or prolonged exposure in severely immunocompromised patients may select herpesvirus strains with reduced sensitivity.
• Account for the vial's sodium content in patients requiring sodium restriction.

Contraindications and cautions

• Hypersensitivity to aciclovir, valaciclovir or an excipient.
• Do not re-expose patients who developed a severe cutaneous adverse reaction with aciclovir or valaciclovir.

Monitoring

• Renal function and urine output, with increased vigilance in dehydration, older age or renal impairment
• Hydration and evidence of crystalluria or renal pain
• Neurological status, especially in older people and those with impaired renal function
• Infusion site for phlebitis, extravasation and tissue injury
• Relevant medicine concentrations when lithium or theophylline are co-administered
• Liver tests and blood counts when clinically indicated

Clinical pharmacology

Aciclovir is selectively phosphorylated in infected cells and converted to aciclovir triphosphate, which inhibits viral DNA polymerase and causes DNA-chain termination. It has low protein binding, reaches cerebrospinal fluid, and is eliminated predominantly unchanged through glomerular filtration and active tubular secretion; clearance therefore depends strongly on renal function.

Formulation and product differences

• The selected product is aciclovir sodium powder requiring aseptic reconstitution and intravenous administration.
• The reconstituted solution is alkaline, contains no antimicrobial preservative and must not be given orally.
• Only compatible infusion fluids specified in the product information should be used; discard preparations showing turbidity or crystallisation.
• This intravenous presentation differs from oral, topical and ophthalmic aciclovir products in administration, systemic exposure and monitoring requirements.

Solution for infusion

Route: Intravenous

Strengths: 25 mg/mL, 250 mg