Acyclovir in dermatology

0
18
0
Share the knowledge

Acyclovir in dermatology

Indications of acyclovir in dermatology

  • Herpes simplex – primary: 200–400 mg 5×/day for 10 days or 5 mg/kg IV q8h for 7–10 days.
  • Herpes simplex – recurrent :At least 400 mg TID for 5 days or 800 mg two times/day for 5 days.
  • Suppressive therapy :At least 400 mg BID.
  • Chicken pox
    • (children): 20 mg/kg 4 times daily (up to a maximum of 800 mg per dose).
    • (adults) : 800 mg 5 times daily for 7 days.
  • Herpes zoster(adults) : 800 mg 5×/day for 7–10 days.
  • Herpes simplex or varicella-zoster infections in immunocompromised patients : 10 mg/kg three times daily IV for 7–10 days.
  • Eczema herpeticum : 15 mg/kg (400 mg max) po 3–5×/d or, if severe, 5 mg/kg (if age ≥12y) to 10 mg/kg (if age <12y) iv q8h.
  • primary genital herpes : 200 mg five times a day, 400 mg every 8 hours, or 800 mg orally every 12 hours for 7-10 days.
  • Severe genital herpes or immunocompromised : 5 mg/kg IV every 8 hours for 7 days.
  • Recurrent genital herpes : 400 mg every 8 hrs for 5 days.
  • Hand-foot and-mouth disease : 200 to 300 mg five times a day for 5 days (anecdotally reported to provide rapid relief of signs and symptoms).
  • Herpes simplex folliculitis: 200 mg po 5 times per day for 5–10 days.
  • Herpetic whitlow
    • primary: 200 mg five times/day for 7-10 days.
    • recurrent :400 mg three times/day for 5 days.
  • Pityriasis Rosea( severe cases) : 400 mg five times a day for a week or 800 mg five times daily for 1 week.
  • Neonatal HSV infection:
    • herpetic skin lesions : (early) 30 mg/kg/day.
    • disseminated and CNS disease: 20 mg/kg iv every 8 hours for 21 days.
    • skin and mucous membranes affection: 20 mg/kg iv every 8 hours for 14 days.
  • Recurrent erythema multiforme (presumed/proven due to HSV): 10 mg/kg/day in divided doses for 6 months.

Dosage

  • HERPES SIMPLEX PRIMARY
    • Immunocompetent: 200 mg PO 5 times a day for 10 days.
    • Immunodeficient: 200–400 mg PO 5 times a day for 10 days or 5 mg/kg IV q8h for 7–10 days.
  • HERPES SIMPLEX RECURRENCES
    • Immunocompetent: 400 mg PO tid for 5 days.
    • Immunodeficient: 400 mg PO 5 times a day for 7–10 days or 5 mg/kg IV q8h for 7 days.
  • HERPES SIMPLEX SUPPRESSION
    • Immunocompetent: 400 mg PO bid.
    • Immunodeficient: 400–800 mg 2×/day.
  • VARICELLA
    • Immunocompetent: 20 mg/kg PO 5 times a day up to 800 mg/dose PO 5 times a day for 5–7 days.
    • Immunodeficient: 10 mg/kg IV q8h for 7–10 days.
  • HERPES ZOSTER
    • Immunocompetent: 800 mg PO 5 times a day for 7–10 days.
    • Immunodeficient: 10 mg/kg IV q8h for 7–10 days.
  • RENAL DOSING IV
    • Creatinine clearance (CrCl) 50–90 mL/min: 5–12.4 mg/kg IV q8h.
    • CrCl 10–50 mL/min: 5–12.4 mg/kg IV q12h–q24h.
    • CrCl < 10 mL/min: 2.5 mg/kg IV q24h.
    • Hemodialysis: 2.5 mg/kg IV after dialysis.
    • Chronic ambulatory peritoneal dialysis: 2.5 mg/kg IV q24h.
    • Continuous arteriovenous hemofiltration: 3.5 mg/kg/d IV.

Mechanism of action

  • It is phosphorylated by viral thymidine kinase to acyclovir monophosphate and then enzymes in the host cell convert it to acyclovir triphosphate, which inactivates viral DNA polymerase,mpreventing viral DNA synthesis and thus replication.

Side effects

  • Malaise.
  • Gastrointestinal: Nausea, vomiting, diarrhea, and headache.
  • Hematologic : aplastic anemia, leukopenia, thrombocytopenia.
  • Neurologic: headaches, vertigo, lethargy, confusion,hallucinations, depression, seizures, encephalopathy, coma (CNS disturbances more likely in elderly patients).
  • Cardiovascular: hypertension, tachycardia, anaphylaxis.
  • Intravenous infusions: may be associated with phlebitis and infusion-site inflammation.

Changing infusion sites and decreasing final infusion concentration less than 10 mg/mL can help prevent phlebitis at the infusion site.

  • Reversible crystalluria-induced nephropathy with intravenous acyclovir (typically in patients with pre-existing renal dysfunction or dehydration).
  • Other: malaise, arthralgia, myalgia, dyspnea, dysmenorrhea

Contraindications

  • Hypersensitivity to drug/class.

Interactions

  • Increaded levels of acyclovir : probenecid, zidovudine, Amphotericin, Cimetidine, Mycophenolate mofetil.
  • Glyburide with metformin : Acyclovir or valacyclovir may cause lactic acidosis in patients with decreased renal function.
  • Interferon :May worsen potential neurotoxicity of acyclovir.
  • Intrathecal methotrexate :May worsen potential neurotoxicity of acyclovir.
  • Nephrotoxic drugs (i.e. cisplatin) :Acyclovir increases risk of nephrotoxicity.
  • Theophylline :Acyclovir causes decreased metabolism and increased serum levels of theophylline.

Pregnancy &Lactation

  • Pregnancy category B .
  • Drug enters breast milk; use with caution

Precautions

  • Avoid rapid infusion because of risk of renal damage.
  • Use with caution in immunocompromised patients (potential risk of thrombotic thrombocytopenic purpura /hemolytic uremic syndrome ).
  • Use with caution in patients receiving nephrotoxic drugs.
  • Maintain adequate hydration during PO or IV therapy.

Drug Info

  • For efficacious treatment of chicken pox, acyclovir must be initiated within the first 24–72 hours after appearance of the characteristic skin eruption.
  • Intravenous acyclovir is reserved for severe illness and in immunocompromised patients.
  • Foscarnet is the only antiviral drug approved by the FDA for treatment of acyclovir-resistant HSV.

Was this helpful?

18 / 0


Share the knowledge
Leave a Reply 0