Pronunciation: Online audio
Category B (PO, IV)
Category C (topical)
- PO: Recurrent genital herpes infections. Localized cutaneous herpes zoster infections (shingles) and chickenpox (varicella).
- IV: Severe initial episodes of genital herpes in nonimmunosuppressed patients. Mucosal or cutaneous herpes simplex infections or herpes zoster infections (shingles) in immunosuppressed patients. Herpes simplex encephalitis.
- Topical: Cream–Recurrent herpes labialis (cold sores). Ointment–Treatment of limited non–life-threatening herpes simplex infections in immunocompromised patients (systemic treatment is preferred).
Interferes with viral DNA synthesis.
Inhibition of viral replication, decreased viral shedding, and reduced time for healing of lesions.
Absorption: Despite poor absorption (15–30%), therapeutic blood levels are achieved.
Distribution: Widely distributed. CSF concentrations are 50% of plasma. Crosses placenta; enters breast milk.
Protein Binding: <30%.
Metabolism and Excretion: >90% eliminated unchanged by kidneys; remainder metabolized by liver.
Half-life: Neonates: 4 hr; Children 1–12 yr: 2–3 hr; Adults: 2–3.5 hr (↑ in renal failure).
TIME/ACTION PROFILE (antiviral blood levels)
|PO||unknown||1.5–2.5 hr||4 hr|
|IV||prompt||end of infusion||8 hr|
Hypersensitivity to acyclovir or valacyclovir.
Use Cautiously in:
- Pre-existing serious neurologic, hepatic, pulmonary, or fluid and electrolyte abnormalities
- Renal impairment (dose alteration recommended if CCr <50 mL/min)
- Geri: Due to age related ↓ in renal function
- Obese patients (dose should be based on ideal body weight)
- Patients with hypoxia
- OB: Lactation: Safety not established.
Adverse Reactions/Side Effects
CNS: SEIZURES, dizziness, headache, hallucinations, trembling
GI: diarrhea, nausea, vomiting, ↑ liver enzymes, hyperbilirubinemia, abdominal pain, anorexia
GU: RENAL FAILURE, crystalluria, hematuria, renal pain
Derm: STEVENS-JOHNSON SYNDROME, acne, hives, rash, unusual sweating
Endo: changes in menstrual cycle
Hemat: THROMBOTIC THROMBOCYTOPENIC PURPURA/HEMOLYTIC UREMIC SYNDROME (HIGH DOSES IN IMMUNOSUPPRESSED PATIENTS)
Local: pain, phlebitis, local irritation
MS: joint pain
* CAPITALS indicate life-threatening.
Italics indicate most frequent.
- Probenecid ↑ blood levels of acyclovir.
- ↑ blood levels and risk of toxicity from theophylline; dose adjustment may be necessary.
- ↓ blood levels and may ↓ effectiveness of valproic acid or phenytoin.
- Concurrent use of other nephrotoxic drugs ↑ risk of adverse renal effects.
- Zidovudine and IT methotrexate may ↑ risk of CNS side effects.
Initial Genital Herpes
PO: (Adults and Children) 200 mg q 4 hr while awake (5 times/day) for 7–10 days or 400 mg q 8 hr for 7–10 days; maximum dose in children: 80 mg/kg/day in 3–5 divided doses.
IV: (Adults and Children) 5 mg/kg q 8 hr or 750 mg/m2/day divided q 8 hr for 5–7 days.
Chronic Suppressive Therapy for Recurrent Genital Herpes
PO: (Adults and Children) 400 mg twice daily or 200 mg 3–5 times/day for up to 12 mo. Maximum dose in children: 80 mg/kg/day in 2–5 divided doses.
Intermittent Therapy for Recurrent Genital Herpes
PO: (Adults and Children) 200 mg q 4 hr while awake (5 times/day) or 400 mg q 8hr or 800 mg q 12 hr for 5 days, start at first sign of symptoms. Maximum dose in children: 80 mg/kg/day in 2–5 divided doses.
Acute Treatment of Herpes Zoster in Immunosuppressed Patients
PO: (Adults) 800 mg q 4 hr while awake (5 times/day) for 7–10 days. Prophylaxis–400 mg 5 times/day.
PO: Children 250–600 mg/m2/dose 4–5 times/day.
Herpes Zoster in Immunocompetent Patients
PO: (Adults and Children) 4000 mg/day in 5 divided doses for 5–7 days, maximum dose in children: 80 mg/kg/day in 5 divided doses.
PO: (Adults and Children) 20 mg/kg (not to exceed 800 mg/dose) qid for 5 days. Start within 24 hr of rash onset.
Mucosal and Cutaneous Herpes Simplex Infections in Immunosuppressed Patients
IV: (Adults and Children >12 yr): 5 mg/kg q 8 hr for 7 days.
IV: (Children <12 yr): 10 mg/kg q 8 hr for 7 days.
Topical: (Adults) 0.5 in. ribbon of 5% ointment for every 4-square-in. area q 3 hr (6 times/day) for 7 days.
Herpes Simplex Encephalitis
IV: (Adults) 10 mg/kg q 8 hr for 14–21 days.
IV: (Children 3 mo–12 yr): 10 mg/kg q 8 hr for 14–21 days.
IV: (Children birth–3 mo): 20 mg/kg q 8 hr for 14–21 days.
IV: (Neonates , premature): 10 mg/kg q 12 hr for 14–21 days.
Varicella Zoster Infections in Immunosuppressed Patients
IV: (Adults) 10 mg/kg q 8 hr for 7–10 days.
IV: (Children <12 yr): 10 mg/kg q 8 hr for 7–10 days.
PO: IV: (Adults and Children) CCr >50 mL/min/1.73 m2–no dosage adjustment needed; CCr 25 –50 mL/min/1.73 m2–administer normal dose q 12 hr; CCr 10–25 mL/min/1.73 m2–administer normal dose q 24 hr; CCr 0–10 mL/min/1.73 m2–50% of dose q 24 hr.
IV: Neonates SCr 0.8–1.1 mg/dL: Administer 20 mg/kg/dose q 12 hr; SCr 1.2–1.5 mg/dL: Administer 20 mg/kg/dose q 24 hr; SCr >1.5 mg/dL: Administer 10 mg/kg/dose q 24 hr.
Topical: (Adults and Children >12 yr): Apply 5 times/day for 4 days; start at first symptoms.
Availability (generic available)
Capsules: 200 mg
Tablets: 400 mg, 800 mg
Suspension (banana flavor): 200 mg/5 mL
Powder for injection: 500 mg/vial, 1000 mg/vial
Solution for injection: 25 mg/mL, 50 mg/mL
In Combination with: hydrocortisone (Xerese). See combination drugs.
- Assess lesions before and daily during therapy.
- Monitor neurologic status in patients with herpes encephalitis.
Lab Test Considerations:
Monitor BUN, serum creatinine, and CCr before and during therapy. ↑ BUN and serum creatinine levels or ↓ CCr may indicate renal failure.
- Do not confuse Zovirax with Doribax, Zyvox, or Zostrix.
- Start acyclovir treatment as soon as possible after herpes simplex symptoms appear and within 24 hr of a herpes zoster outbreak.
- PO: Acyclovir may be administered with food or on an empty stomach, with a full glass of water.
- Shake oral suspension well before administration.
Topical: Apply to skin lesions only; do not use in the eye.
- Instruct patient to take medication as directed for the full course of therapy. Take missed doses as soon as possible but not just before next dose is due; do not double doses. Acyclovir should not be used more frequently or longer than prescribed.
- Advise patients that the additional use of OTC creams, lotions, and ointments may delay healing and may cause spreading of lesions.
- Inform patient that acyclovir is not a cure. The virus lies dormant in the ganglia, and acyclovir will not prevent the spread of infection to others.
- Advise patient that condoms should be used during sexual contact and that no sexual contact should be made while lesions are present.
- Patient should consult health care professional if symptoms are not relieved after 7 days of topical therapy or if oral acyclovir does not decrease the frequency and severity of recurrences. Immunocompromised patients may require a longer time, usually 2 weeks, for crusting over of lesions.
- Instruct women with genital herpes to have yearly Papanicolaou smears because they may be more likely to develop cervical cancer.
- Topical: Instruct patient to apply ointment in sufficient quantity to cover all lesions every 3 hr, 6 times/day for 7 days. 0.5-in. ribbon of ointment covers approximately 4 square in. Use a finger cot or glove when applying to prevent inoculation of other areas or spread to other people. Keep affected areas clean and dry. Loose-fitting clothing should be worn to prevent irritation.
- Avoid drug contact in or around eyes. Report any unexplained eye symptoms to health care professional immediately; ocular herpetic infection can lead to blindness.
- Crusting over and healing of skin lesions.
- Decrease in frequency and severity of recurrences.
- Acceleration of complete healing and cessation of pain in herpes zoster.
- Decrease in intensity of chickenpox.