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Acyclovir Dosage

Medically reviewed by Drugs.com. Last updated on Jul 24, 2023.

Applies to the following strengths: 200 mg; 500 mg; 1000 mg; 800 mg; 400 mg; 200 mg/5 mL; 50 mg/mL; 25 mg/mL; 50 mg

Usual Adult Dose for Herpes Simplex - Mucocutaneous/Immunocompetent Host

Treatment of First Episode of Genital Herpes:
200 mg orally every 4 hours 5 times a day for 10 days (manufacturer dosing)
400 mg orally 3 times a day for 5 to 10 days (CDC recommendation)

Severe Disease or Complications Requiring Hospitalization:
5 mg/kg IV every 8 hours for 5 days (manufacturer dosing)
5 to 10 mg/kg IV every 8 hours for 2 to 7 days or until clinical improvement is observed, followed by oral antiviral therapy to complete at least 10 days of total therapy (CDC recommendation)

Episodic (Intermittent) Therapy: Effective treatment requires therapy initiation within 1 day of lesion onset or during the prodrome preceding an episode/recurrence
200 mg orally every 4 hours 5 times a day for 5 days (manufacturer dosing)
400 mg orally 3 times a day for 5 days OR 800 mg orally 2 times a day for 5 days OR 800 mg orally 3 times a day for 2 days (CDC recommendations)

Comments:


Use: For the initial treatment and recurrent episodes of mucosal and cutaneous herpes simplex (HSV-1 and HSV-2).

Usual Adult Dose for Herpes Simplex - Mucocutaneous/Immunocompromised Host

Concomitant HIV infection:

400 mg orally 3 times a day for 5 to 10 days (guideline recommendation)
Duration of therapy: 5 to 10 days

5 mg/kg IV every 8 hours after lesions begin to regress, may change to oral therapy; continue treatment until lesions have completely healed (guideline recommendation)

Episodic (Intermittent) Therapy: Effective treatment requires therapy initiation within 1 day of lesion onset or during the prodrome preceding an episode/recurrence
400 mg orally 3 times a day for 5 to 14 days

Comments:

Use: For the treatment of initial and recurrent mucosal and cutaneous herpes simplex (HSV-1 and HSV-2) in immunocompromised patients.

Usual Adult Dose for Herpes Simplex Encephalitis

10 mg/kg IV every 8 hours
Duration of therapy: 10 days (manufacturer); 21 days (CDC)

Comments:


Use: For the treatment of HSV encephalitis.

Usual Adult Dose for Herpes Zoster

800 mg orally every 4 hours 5 times a day for 7 to 10 days

Immunocompromised host:
10 mg/kg IV every 8 hours for 7 days

Concomitant HIV infection:

Duration of therapy: 7 to 14-day course (oral plus IV)

Comments:

Use: For the acute treatment of herpes zoster (shingles).

Usual Adult Dose for Varicella-Zoster

Immunocompetent Host: 800 mg orally 4 times a day for 5 days
Immunocompromised Host: 10 mg/kg IV every 8 hours for 7 days

HIV-Infected Adults:


Comments:

Use: For the treatment of chickenpox (varicella).

Usual Adult Dose for Herpes Simplex Labialis

Immunocompetent host:
Apply 50 mg (1 buccal tablet) as a single-dose to the upper gum region (canine fossa)

Comments:


Concomitant HIV infection:
Oral tablets: 400 mg orally 3 times a day for 5 to 10 days

Comment: Guidelines for the Prevention and Treatment of Opportunistic Infections Among HIV- Infected Adults and Adolescents may be consulted for additional guidance.

Use: For the treatment of herpes simplex labialis (cold sores).

Usual Adult Dose for Herpes Simplex - Suppression

Daily Suppressive Therapy for Recurrent Disease: 400 mg orally 2 times a day


Concomitant HIV infection: 400 to 800 mg orally 2 to 3 times a day

Comments:
HSV compared with those receiving episodic therapy; however, resistance is possible and should be suspected and investigated if lesions persist or recur.

Use: For secondary prophylaxis and treatment of recurrent HSV disease.

Usual Adult Dose for Herpes Zoster - Prophylaxis

HIV-Infected Adults (guideline dosing):


Comments:

Use: For HIV-infected person who has had close contact with a person who has active varicella or herpes zoster and is susceptible to the virus (e.g. no history of vaccination or either condition, or is known to be seronegative).

Usual Adult Dose for Varicella-Zoster - Prophylaxis

HIV-Infected Adults (guideline dosing):


Comments:

Use: For HIV-infected person who has had close contact with a person who has active varicella or herpes zoster and is susceptible to the virus (e.g. no history of vaccination or either condition, or is known to be seronegative).

Usual Pediatric Dose for Herpes Simplex - Congenital

Neonatal Herpes:
Birth to 3 months: 10 mg/kg IV every 8 hours for 10 days (manufacturer dosing)

Birth to 3 months: 20 mg/kg IV every 8 hours (CDC recommendation)


Follow with oral suppressive therapy: 300 mg/m2 orally 3 times a day for 6 months

Comments:

Use: For known or suspected neonatal HSV.

Usual Pediatric Dose for Herpes Simplex - Mucocutaneous/Immunocompetent Host

Treatment of First Episode of Genital Herpes:
Less than 12 years: 40 to 80 mg/kg/day orally in divided doses 3 to 4 times a day for 5 to 10 days
Maximum dose: 1000 mg/day

12 years or older: 200 mg orally every 4 hours 5 times a day OR 400 mg orally 3 times a day
Duration of therapy: 7 to 10 days

Severe Disease or Complications Requiring Hospitalization:
Less than 12 years: 10 mg/kg IV every 8 hours for 7 days
12 years or older: 5 mg/kg IV every 8 hours for 7 days

Recurrence of Genital HSV Infection:
Less than 12 years: 20 to 25 mg/kg orally twice a day; Maximum dose: 400 mg
12 years or older: 200 mg orally 5 times a day for 5 days OR 800 mg orally 2 times a day for 5 days OR 800 mg orally 3 times a day for 2 days

Comments:


Use: For the treatment of first episode or recurrence of mucosal and cutaneous herpes simplex (HSV-1 and HSV-2).

Usual Pediatric Dose for Herpes Simplex Encephalitis

3 months to 12 years old: 10 to 20 mg/kg IV every 8 hours

12 years or older: 10 mg/kg IV every 8 hours

Duration of therapy: 10 days (manufacturer); 21 days (CDC)

Comments:


Use: For the treatment of Herpes Simplex Encephalitis

Usual Pediatric Dose for Herpes Simplex - Mucocutaneous/Immunocompromised Host

Less than 12 years: 10 mg/kg IV every 8 hours for 7 days (manufacturer dosing)
12 years or older: 5 mg/kg IV every 8 hours for 7 days (manufacturer dosing)

Concomitant HIV infection (guideline dosing):

20 mg/kg orally 4 times a day for 7 to 10 days
Maximum dose: 400 mg
5 to 10 mg/kg IV 3 times a day

Comments:

Use: For the treatment of initial and recurrent mucosal and cutaneous herpes simplex (HSV-1 and HSV-2) in immunocompromised patients

Usual Pediatric Dose for Herpes Zoster

Immunocompetent Host:

Less than 1 year: 10 mg/kg IV every 8 hours for 7 to 10 days
1 year or older: 500 mg/m2 IV every 8 hours for 7 to 10 days

Immunocompromised Host: 10 mg/kg IV every 8 hours for 7 to 10 days

HIV-exposed and HIV-Infected Children:
20 mg/kg orally 4 times a day for 7 to 10 days; Maximum dose: 800 mg
10 mg/kg IV every 8 hours until cutaneous lesions and visceral disease are clearly resolving; then may switch to oral therapy to complete a 10 to 14-day course

HIV-Infected Adolescents:
Duration of therapy: 7 to 14-day course (oral plus IV)

Comments:

Use: For the acute treatment of herpes zoster (shingles).

Usual Pediatric Dose for Varicella-Zoster

Immunocompetent host:
2 years or older (40 kg or less): 20 mg/kg orally 4 times a day for 5 days
2 years or older (over 40 kg): 800 mg orally 4 times a day for 5 days
Maximum doses: Single: 800 mg; Daily: 3200 mg/day

Immunocompromised host:
Less than 1 year: 10 mg/kg IV 3 times a day for 7 to 10 days
1 year or older: 500 mg/m2 IV 3 times a day for 7 to 10 days

HIV-exposed and HIV-infected Children

Maximum dose: 800 mg

HIV-Infected Adolescents:

Comments:

Use: For the treatment of chickenpox (varicella).

Usual Pediatric Dose for Herpes Simplex - Suppression

Neonatal period (less than 1 year): 300 mg/m2 orally 3 times a day for 6 months

Secondary Prophylaxis in HIV-Exposed and HIV-infected Children:
20 mg/kg orally twice a day
Maximum dose: 800 mg

Comments:


Use: For the secondary prophylaxis of recurrent HSV disease.

Usual Pediatric Dose for Herpes Simplex Labialis

Concomitant HIV infection:

20 mg/kg orally 4 times a day for 5 days
Maximum dose: 400 mg

Adolescents: 400 mg orally 3 times a day for 5 to 10 days

Comments:


Use: For the treatment of recurrent herpes simplex labialis (cold sores).

Usual Pediatric Dose for Herpes Zoster - Prophylaxis

HIV-Infected Children or Adolescents (guideline dosing):

Post-exposure Prophylaxis in HIV-Infected Children or Adolescents:
20 mg/kg orally 4 times a day (maximum dose 800 mg) for 7 days beginning 7 to 10 days after exposure

Comments:


Use: For HIV-infected person who has had close contact with a person who has active varicella or herpes zoster and is susceptible to the virus (e.g. no history of vaccination or either condition, or is known to be seronegative).

Usual Pediatric Dose for Varicella-Zoster - Prophylaxis

HIV-Infected Children or Adolescents (guideline dosing):

Post-exposure Prophylaxis in HIV-Infected Children or Adolescents:
20 mg/kg orally 4 times a day (maximum dose 800 mg) for 7 days beginning 7 to 10 days after exposure

Comments:


Use: For HIV-infected person who has had close contact with a person who has active varicella or herpes zoster and is susceptible to the virus (e.g. no history of vaccination or either condition, or is known to be seronegative).

Renal Dose Adjustments

Oral:
For CrCl 0 to 10 mL/min/1.73 m2:


For CrCl 10 to 25 mL/min/1.73 m2:

IV:
For CrCl 0 to 10 mL/min/1.73 m2: Give 50% of dose every 24 hours
For CrCl 10 to 25 mL/min/1.73 m2: Give 100% of dose every 24 hours
For CrCl 25 to 50 mL/min/1.73 m2: Give 100% of dose every 12 hours
For CrCl greater than 50 mL/min/1.73 m2: Give 100% of dose every 8 hours

Liver Dose Adjustments

No adjustment recommended

Dose Adjustments

Obese patients should be dosed at the recommended doses using Ideal Body Weight (IBW)

Elderly patients are more likely to have reduced renal function and require dose reduction.

Precautions

Safety and efficacy of oral formulations have not been established in patients younger than 2 years.
Safety and efficacy of buccal tablets have not been established in pediatric patients.

Consult WARNINGS section for additional precautions.

Dialysis

Hemodialysis: Adjust dosing interval to provide an additional dose after each dialysis
Peritoneal Dialysis: No supplemental dose necessary after adjustment of the dosing interval

Other Comments

Administration advice:


Parenteral:

Oral:

Buccal tablet:

Reconstitution/storage/preparation techniques:

IV compatibility: Standard, commercially available electrolyte and glucose solutions are suitable for IV administration; biologic or colloidal fluids (e.g., blood products, protein solutions) are not recommended

General:

Monitoring:

Patient advice:

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.