Acyclovir

C. diff Risk

None

Oral Bioavailability

Moderate

Spectrum Of Activity

Dosing

HSV:

Herpes labialis:
200-400 mg PO 5 times per day x 5 days

Genital (primary or nonprimary episode):
200 mg PO 5 times per day x 5-10 days

Recurrent Genital Lesions:
200 mg PO 5 times per day x 5 days
OR
800 mg PO TID x 2 days
Initiate at onset of symptoms

Unable to take oral or severe mucocutaneous infection: 5 mg/kg IV Q8H
(Switch to oral once improved).

Serious Infections
(e.g. CNS and Disseminated): 10mg/kg IV q8h

VZV/Zoster:

Chicken Pox in Adulthood:
800mg PO QID x 5 days

Shingles:
800 mg 5 times per day x 7-10 days

Serious Infections
(e.g. CNS and Disseminated)
10-15 mg/kg IV q8h (higher doses typically reserved in HIV/immune compromise - see full guidelines or consult ID for details)

Prophylaxis dosing varies by indication refer to specific treatment guidelines.

See Canadian Guidelines on Sexually Transmitted Infections for full management recommendations for HSV.

Manufacturer recommends dosing using IBW (ideal body weight) but can consider adjusted body weight (IBW + 0.4x[TBW-IBW]) for severe (CNS or other) infections.

CrCl Greater Than 50 mL/minCrCl 25-49 mL/minCrCl 10-24 mL/minCrCl Less Than 10 mL/minUsual dosingReduce dosing to q12hReduce doing to q24h50% dose q24h

CrCl Greater Than 50 mL/minCrCl 25-49 mL/minCrCl 10-24 mL/minCrCl Less Than 10 mL/minNo dose adjustment requiredNo dose adjustment requiredIf dose was Reduce to
800 mg 5x/day 800 mg TID
800 mg QID 800 mg TID
800 mg TID 800 mg TID
400 mg 5x/day 400 mg TID
200 mg 5x/day No adjustment
--- ---
800 mg 5x/day 800 mg BID
800 mg QID 800 mg BID
800 mg TID 800 mg BID
400 mg 5x/day 400 mg BID
200 mg 5x/day 200 mg BID

General Information

Follow SCr as appropriate.

Check urine for crystals if AKI suspected.

  •  GI upset

  •  Phlebitis

  •  Increased SCr

  •  AKI from crystal nephropathy

Mycophenolate can increase the acyclovir concentration.

May diminish efficacy of zoster or varicella vaccine.

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

Antimicrobial class: Antiviral. Nucleoside analogue.

Pregnancy category: B

Average serum half life: 3 hours, longer if renal dysfunction

CSF penetration: Therapeutic

Urine penetration: Therapeutic

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

Prophylaxis of herpesviral infections if recurrent disease or immunocompromised.