Antimicrobials
Acyclovir

Acyclovir

None
Low
IV: $$ PO: $ tablet, $$ suspension

Spectrum of Activity

General Information

  • Therapy for herpes virus infections (HSV and VZV) including encephalitis
  • Prophylaxis of herpes virus infections if recurrent disease or immunocompromised

Neonatal:

  • Monitor ANC at least twice weekly during treatment. Reduce dose if ANC is <0.5x10⁹/L
  • Serum creatinine and urea twice weekly
  • Monitor injection site closely during infusion

May cause:

  • Nausea
  • Vomiting
  • Diarrhea
  • Headache
  • Dizziness
  • Neurotoxicity
  • Arthralgia
  • Fatigue
  • Rash
  • Insomnia
  • Fever

Neonatal:

  • Transient renal dysfunction associated with rapid infusion or large doses
  • Phlebitis at injection site due to high pH of drug
  • Neutropenia (ANC <1x10⁹/L), which is reversible
  • May diminish efficacy of zoster or varicella vaccine
  • May decrease clearance of methotrexate
  • Tablet: 200mg
  • Suspension: 40 mg/1mL
  • Injection: 500 mg/vial

Neonatal:

  • IV: 500mg vial (50 mg/mL)
  • Oral absorption is unpredictable (15-30%). Valacyclovir is an oral prodrug of acyclovir and offers improved bioavailability
  • Keep well hydrated to prevent nephrotoxicity due to crystallization in renal tubules
  • In obese patients, calculate dosage using ideal body weight

Antimicrobial class: Antiviral, nucleoside analogue

Average serum half life: Neonates: 4 hours Children 1-12 years: 2-3 hours

Route of Elimination: Primarily kidney with 60-90% of drug excreted unchanged in the urine