Pharm

Acyclovir

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Acyclovir, Zovirax, Sitavig

  • See Also
  1. Famciclovir
  2. Valacyclovir
  • Indications
  1. Primary or Recurrent Herpes Simplex Virus Infection
    1. Oral Herpes (Herpes Labialis)
    2. Genital Herpes
  2. HSV Encephalitis
  3. HSV Keratitis
  4. Herpes Neonatorum
  5. Herpes Zoster
  6. Genital Herpes
  7. Varicella Zoster Virus
  8. Herpes Zoster Ophthalmicus
  9. Herpes Labialis
  • Contraindications
  1. Milk Protein concentrate allergy
  • Mechanism
  1. Prodrug metabolized by multiple enzymes (e.g. thymidine kinase) to active triphosphate agent
  2. Inhibits viral DNA Polymerase
  • Medications
  1. Tablets: 200, 400, 800 mg
  2. Suspension: 200 mg/5 ml
  3. Buccal tablet (Sitavig)
    1. Must stay in place in buccal space until dissolves (6 hours)
    2. Replace if buccal tablet falls off before 6 hours
    3. Do not chew gum while tablet is in place
  1. Primary Herpetic Gingivostomatitis
    1. Adult: 200 mg orally every 4 hours while awake (5x/day)
    2. Ped: 15 mg/kg/day (750 mg/m2/day) divided five times daily for 5 days
  2. Episodic, recurrent Orolabial Herpes
    1. Topicals
      1. Acyclovir cream apply 5 times per day for 4 days
      2. Sitavig buccal one tablet per episode placed in upper gum on same side of mouth as symptoms
        1. Very expensive ($300 for 2 tabs in 2014) and only shortens Cold Sore course by <1 day
        2. (2014) Presc Lett 21(9): 53
    2. Systemic
      1. Child: 15 mg/kg (max: 200 mg) orally 5 times per day for 5 days
      2. Adult: 400 mg orally 3 times daily for 5 days (or 200 mg orally 5 times daily for 5 days)
  • Dosing
  • Herpes Neonatorum
  1. HSV Encephalitis or Herpes Neonatorum
    1. Child: 30 mg/kg/day (1500 mg/m2/day) divided every 8 hours IV
  1. Initial Genital HSV
    1. Adult: 200 mg orally 5 times per day (or every 4 hours) for 10 days
  2. Episodic Genital HSV
    1. Adult: 200 mg orally 5 times per day for 5 days
    2. Apply topical Acyclovir to affected area 6 times per day for 7 days
  3. Prophylaxis of Genital HSV
    1. Adult: 400 mg orally twice daily for up to 12 months
  • Dosing
  • Varicella Zoster
  1. Precaution: Adust IV dosing in obese patients
    1. Use Adjusted body weight (ABW), which is 120% of Ideal Body Weight
  2. Herpes Zoster (Shingles) or Herpes Ophthalmicus
    1. Adult Oral: 800 mg orally 5 times/day for 7-10 days
    2. Adult IV: 10-12 mg/kg/dose every 8 hours for 7-14 days
  3. Varicella Zoster Virus (Chicken Pox)
    1. Child
      1. Dose: 10-20 mg/kg/dose to 800 mg orally four times daily for 5 days
    2. Adult
      1. Dose: 600-800 mg/dose orally every 4 hours while awake (5x/day)
      2. Dose: 1000 mg/dose orally every 6 hours for 5 days
    3. Intravenous
      1. Dose: 30 mg/kg/day (1500 mg/m2/day) divided every 8 hours IV
  • Dosing
  • Renal
  1. eGFR 25 to 50 ml/min: Give usual dose every 12 hours
  2. eGFR 10 to 25 ml/min: Give usual dose every 24 hours
  3. eGFR <10 ml/min: Give 50% of usual dose every 24 hours
  4. Give another dose following each Hemodialysis session
  • Adverse Effects
  1. Headache
  2. Gastrointestinal Upset
  3. Impaired Renal Function
  4. CNS depression
    1. Lethargy
    2. Confusion
    3. Coma
  5. Tremors
  6. Agitation
  • Pharmacokinetics
  1. Base Weight calculations on Lean Body Mass
  2. Metabolized by Kidney
    1. Decrease interval in renal Impairment to q12-24h
  3. Hemodialysis: 50-100% dialyzable
  1. FDA Pregnancy Class C
  2. Safety unclear in Breast Feeding
  • Drug Interactions (prolong Acyclovir half life)
  1. Probenecid
  2. Zidovudine
  • Precautions
  1. Overdose may result in Renal Failure
  2. Maintain adequate urine to flush renal tubules
  3. Avoid rapid infusion (risk of crystal nephropathy)
  4. Base intravenous dosing on adjusted body weight (120% of Ideal Body Weight) in obese patients
  1. Only effective if used at outset of symptoms (first sense of Paresthesias such as burning or tingling)
  2. Shortens Vesicle life and decreases shedding
  3. Prevents recurrence in Immunocompromised
  4. Reduction in episodes: 53%
  5. Quicker healing: 4 days instead of 8 for Placebo
  6. Reduction in number of Fever Blisters: 71%
  • Resources
  1. Acyclovir Tablet
    1. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=70038a69-badc-4073-a13e-ebc9bb8146bc
  • References
  1. (2013) Med Lett Drugs Ther 11(127): 19-30 [PubMed]