Spectrum of Activity


General Information


  • Infuse over 1 hour to prevent renal damage
  • Avoid extravasation by checking for phlebitis and rotating infusion sites


  • Reconstitute vials with sterile water (SWFI)
  • Dilute for IV administration in D5W or NS to final concentration of 7 mg/mL or less


  • D5W, NS
  • 0-350mg in 50ml over 1 hr
  • 351-700mg in 100ml over 1 hr


  • D5W, LR, NS

Therapy for herpesviral infections (HSV and VZV) including encephalitis.

Prophylaxis of herpesviral infections if recurrent disease or immunocompromised.

  • Follow SCr and BUN as appropriate

  • CBC

  • Liver enzymes

  • Keep patient hydrated

  • Check urine for crystals if AKI suspected

  • GI upset

  • Phlebitis

  • Thrombotic microangiopathy

  • Increased SCr

  • Decreased Hgb and neutrophils

  • AKI from crystal nephropathy

  • Neurotoxicity

  • Mycophenolate can increase the acyclovir concentration.

  • Foscarnet can enhance nephrotoxic effect of Acyclovir, avoid combination

  • Tizanidine concentration can increase with concomitant administration

  • May diminish efficacy of zoster or varicella vaccine.

Antimicrobial class: Antiviral. Nucleoside analogue.

Oral bioavailability: can improve absorption with multiple small doses compared to larger once daily dosing

Pregnancy category: B

Average serum half life: 3 hours

Urine penetration: Therapeutic

CSF penetration: Therapeutic, concentration is ~50% of plasma

For oral indications, valacyclovir is the pro-drug, which is more bioavailable with more convenient dosing