Medication Guide App

Acyclovir Dosage

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Usual Adult Dose for Herpes Simplex - Mucocutaneous/Immunocompetent Host

Initial episode or intermittent therapy: 200 mg orally every 4 hours (5 times a day) for 10 days
Alternatively, the US Centers for Disease Control and Prevention (CDC) recommends 400 mg orally 3 times a day or 200 mg orally 5 times a day for 7 to 10 days.

Recurrent episodes: 200 mg orally every 4 hours (5 times a day) for 5 days
Alternatively, the CDC recommends 400 mg orally 3 times a day for 5 days, 800 mg orally twice a day for 5 days, or 800 mg orally 3 times a day for 2 days.

Orolabial HSV infection treatment: 400 mg orally 5 times a day for 5 days

IV:
Severe initial episode: 5 to 10 mg/kg IBW IV every 8 hours for 5 to 7 days

Therapy should be initiated at the earliest sign or symptom of primary infection (initial episode) or recurrence.

Usual Adult Dose for Herpes Simplex - Mucocutaneous/Immunocompromised Host

Treatment:
Oral: 400 mg orally every 8 hours for 7 to 14 days
IV: 5 mg/kg IV every 8 hours for 7 to 14 days
Treatment dosages recommended by the CDC.

Episodic outbreaks: 200 mg orally every 4 hours (5 times a day) for 5 to 10 days
Alternatively, the CDC recommends 400 mg orally 3 times a day for 5 to 10 days or 7 to 14 days

Orolabial HSV infection treatment:
HIV-infected patients: 400 mg 3 times a day for 7 to 14 days; dosage recommended by the CDC

Therapy should be initiated at the earliest sign or symptom of primary infection (initial episode) or recurrence. Intravenous therapy is indicated for the treatment of primary infection in immunocompromised patients or patients with severe infection.

Usual Adult Dose for Herpes Simplex Encephalitis

10 to 15 mg/kg IBW IV every 8 hours for 10 to 21 days

Usual Adult Dose for Herpes Simplex - Suppression

Chronic suppressive therapy:
Immunocompetent patient: 400 mg orally twice a day; alternatively, 200 mg orally 3 to 5 times a day may be used
HIV-infected patient: 200 mg orally 3 times a day or 400 mg orally 2 times a day
HIV-infected patient, genital herpes: 400 to 800 mg orally 2 to 3 times a day

The safety and efficacy of daily acyclovir suppressive therapy have been documented among patients treated orally for up to six years. However, since the frequency and severity of recurrences may change over time, patients should be reevaluated after one year of therapy to assess the need for continued administration.

Daily suppressive therapy reduces but does not eliminate asymptomatic viral shedding, thus the extent to which it may prevent transmission of infection to others is unknown.

Usual Adult Dose for Herpes Zoster

Acute herpes zoster:
800 mg orally every 4 hours (5 times a day) for 7 to 10 days
Severe, immunocompromised host: 10 mg/kg IBW IV every 8 hours for 7 to 14 days

Therapy should be initiated within 72 hours after onset of rash, although, during clinical trials, acyclovir was most effective when initiated within the first 48 hours.

Usual Adult Dose for Varicella-Zoster

Chickenpox:
Immunocompetent host: 800 mg orally four times a day for 5 days

Immunocompromised host: 10 mg/kg IBW IV every 8 hours for 7 to 10 days or until no new lesions for 48 hours; after fever abates and if there is no proof of visceral involvement, the patient may be switched to 800 mg orally four times a day

Therapy should be initiated at the earliest sign of chickenpox, no later than 24 hours after onset of rash.

Usual Pediatric Dose for Herpes Simplex

Neonatal HSV infection:
Less than 3 months: 10 to 20 mg/kg or 500 mg/m2 IV every 8 hours for 10 to 21 days
Some clinicians recommend 10 mg/kg every 12 hours for premature neonates.

Usual Pediatric Dose for Herpes Simplex - Mucocutaneous/Immunocompetent Host

3 months to 11 years:
Initial episode: 10 to 20 mg/kg orally 4 times a day or 8 to 16 mg/kg orally 5 times a day for 7 to 10 days
The American Academy of Pediatrics (AAP) recommends 40 to 80 mg/kg orally per day in 3 to 4 divided doses for 5 to 10 days.
Maximum dose: 1 g per day

12 years or older, over 40 kg:
Initial episode, severe initial episode, and recurrent episodes: Adult dose

Usual Pediatric Dose for Herpes Simplex - Mucocutaneous/Immunocompromised Host

Treatment of mucocutaneous HSV infection:
Oral: 1 g orally per day in 3 to 5 divided doses for 7 to 14 days; dosage recommended by the AAP

IV:
3 months to 11 years: 5 to 10 mg/kg or 250 to 500 mg/m2 IV every 8 hours for 7 to 14 days
12 years or older, over 40 kg: Adult dose

Usual Pediatric Dose for Herpes Simplex Encephalitis

3 months to 11 years: 10 to 20 mg/kg or 500 mg/m2 IV every 8 hours for 10 to 21 days
12 years or older: Adult dose

Usual Pediatric Dose for Herpes Simplex - Suppression

Oral:
Less than 12 years: 80 mg/kg/day orally in divided doses 3 to 4 times a day, not to exceed 1 g/day
12 years or older: Adult dose

Immunocompromised host: 5 mg/kg IV every 8 or 12 hours or 250 mg/m2 IV every 8 hours during risk period

Oral acyclovir prophylaxis is recommended by the U.S. Public Health Service and Infectious Diseases Society of America for chronic suppressive therapy in HIV-infected individuals, including infants and children, with frequent or severe recurrences. Daily suppressive therapy reduces but does not eliminate asymptomatic viral shedding, thus the extent to which it may prevent transmission of infection to others is unknown.

Usual Pediatric Dose for Herpes Zoster

Oral:
Immunocompetent host:
12 years or older: 800 mg orally every 4 hours (5 times a day) for 5 to 10 days

HIV-infected host: 20 mg/kg (up to 800 mg per dose) orally 4 times a day for 7 to 10 days; dosage recommended by the CDC

IV:
Immunocompetent host:
Less than 1 year: 10 mg/kg IV every 8 hours for 7 to 10 days
1 year to 11 years: 10 to 20 mg/kg or 500 mg/m2 IV every 8 hours for 7 to 10 days
12 years or older: Adult dose

Immunocompromised host:
Less than 12 years: 10 to 20 mg/kg IV every 8 hours for 7 to 10 days
12 years or older: 10 mg/kg IV every 8 hours for 7 to 10 days

Therapy should be initiated within 72 hours after onset of rash, although, during clinical trials, acyclovir was most effective when initiated within the first 48 hours.

Usual Pediatric Dose for Varicella-Zoster

Chickenpox:
Immunocompetent host:
2 years or older, 40 kg or less: 20 mg/kg orally 4 times a day for 5 days (maximum: 3200 mg/day)
2 years or older, over 40 kg: Adult dose

Immunocompromised host:
Oral:
HIV-infected host: 20 mg/kg (up to 800 mg per dose) orally 4 times a day for 7 days or until no new lesions for 48 hours

IV:
Less than 1 year: 10 mg/kg every 8 hours for 7 to 10 days or until no new lesions for 48 hours
1 year to 12 years: 10 to 20 mg/kg or 500 mg/m2 IV every 8 hours for 7 to 10 days or until no new lesions for 48 hours
12 years or older: Adult dose

Therapy should be initiated at the earliest sign of chickenpox, no later than 24 hours after onset of rash.

Renal Dose Adjustments

Adults and adolescents:
Oral:
Normal dose 200 mg every 4 hours:
CrCl less than 10 mL/min/1.73 m2: 200 mg every 12 hours

Normal dose 400 mg every 12 hours:
CrCl less than 10 mL/min/1.73 m2: 200 mg every 12 hours

Normal dose 800 mg every 4 hours:
CrCl 10 to 25 mL/min/1.73 m2: 800 mg every 8 hours
CrCl less than 10 mL/min/1.73 m2: 800 mg every 12 hours

IV:
CrCl 25 to 50 mL/min/1.73 m2: 100% of normal dose every 12 hours
CrCl 10 to 25 mL/min/1.73 m2: 100% of normal dose every 24 hours
CrCl less than 10 mL/min/1.73 m2: 50% of normal dose every 24 hours

HIV-infected host:
Oral (based on normal dosage of 200 to 800 mg orally every 4 to 6 hours):
CrCl 50 to 80 mL/min/1.73 m2: 200 to 800 mg orally every 6 to 8 hours
CrCl 25 to 50 mL/min/1.73 m2: 200 to 800 mg orally every 8 to 12 hours
CrCl 10 to 25 mL/min/1.73 m2: 200 to 800 mg orally every 12 to 24 hours
CrCl less than 10 mL/min/1.73 m2: 200 to 400 mg orally every 24 hours

IV (based on normal dosage of 5 mg/kg IV every 8 hours):
CrCl 10 to 50 mL/min/1.73 m2: 5 mg/kg IV every 12 to 24 hours
CrCl less than 10 mL/min/1.73 m2: 2.5 mg/kg every 24 hours

Since the pharmacokinetics of acyclovir in pediatric patients are comparable to that in adults, dosages may be reduced similarly in pediatric patients with renal impairment.

Liver Dose Adjustments

No adjustment recommended.

Precautions

Acyclovir has been associated with renal failure, in some cases fatal. Patients receiving acyclovir should be adequately hydrated to prevent renal toxicity secondary to crystalluria. Intravenous acyclovir should not exceed a concentration of 7 mg per mL and should be infused over one hour to minimize crystallization of drug in renal tubules.

Dosage adjustment is recommended when using acyclovir in patients with renal impairment.

Acyclovir should be used with caution in patients receiving other potentially nephrotoxic agents since the concomitant use will increase the risk of renal dysfunction and/or the risk of reversible central nervous system side effects. Adequate hydration should be maintained.

Dialysis

Acyclovir is removed by hemodialysis. Doses should be scheduled to either follow dialysis or a supplemental dose be given after dialysis.

Supplemental doses do not appear necessary after peritoneal dialysis.

Other Comments

When dosing according to weight, the ideal body weight should be used for obese patients.

Intravenous acyclovir should be administered at a constant rate over one hour and adequate hydration maintained to prevent crystallization of acyclovir in the renal tubules.

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