An Overview of Herpes and Zoster Treatment

December 7, 2020

An Overview of Herpes and Zoster Treatment

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0.25 ce credits

Acyclovir (Zovirax®)
Available as: capsules 200mg; tablets 400mg & 800mg  and 200mg/5ml                     
Mechanism: requires 3 phosphorylation steps for activation.  Is selectively activated and accumulates only in infected cells.  It inactivates DNA polymerase.
Indication for Use:

  • Initial and recurrent HSV I and II
  • Treatment of herpes Zoster (shingles)
  • Treatment of varicella (chickenpox)
  • IV used for treatment of herpes simplex encephalitis, neonatal HSV and serious HSV or VZV infections

 
Dosages                

  • initial genital: 400mg 5 times daily for 7-10
  • mucocutaneous oral labial: 400 mg 5 times daily for 5 days
  • Recurrent: 800mg three times daily for 2 days or 400mg three times daily for 5 days
  • Suppression: 400mg twice daily
  • Zoster: 800mg 5 times daily for 7 days. (start within 24 hours of rash)
  • Varicella: 20mg/kg (800mg MAX) four times daily for 5 days. (generally, treatment not recommended)

 
Warnings/precautions:

  • Pregnancy: Category-B
  • Treatment for Zoster is MOST effective when initiated within 48 hours of onset of rash.  After 72 hours of onset, minimal benefit.
  • Renal impairment: dosage adjustment required

 
Adverse Effects

  • Photosensitivity may occur
  • Stevens-Johnson syndrome
  • GI: diarrhea and nausea

 
Drug interactions:

  • May elevate theophylline
  • May lower levels of Phenytoin and Valproic acid

 
Patient Education

  • Avoid sexual intercourse when visible herpes lesions are present.
  • Oral Acyclovir does NOT eliminate latent HSV, and is not a cure
  • May cause photosensitivity, wear sunscreens and protective clothing.
  • May take with or without food

 
Famvir® (Famciclovir)    
Available as: tablets 125mg, 250mg & 500mg
Mechanism:
Gets bio-transformed to penciclovir which is active against HSV I & II, and VZV. Inhibits viral DNA synthesis.
Indication for Use:                                   

  • Zoster: 500mg every 8 hours for 7 days
  • Recurrent genital herpes: 1GM twice daily for 1 day
  • Herpes Simplex (oral or genital) 250mg three times daily for 7-10 days
  • Suppression: 250mg twice daily for up to 1 year
  • Mucocutaneous oral labial: 500mg twice daily for 7 days
  • Famciclovir has been approved as the first and only antiviral to shorten duration of cold sore outbreak with a single dose:
  • Dose: Famciclovir 500mg:  Three tablets (1500mg) as a single dose at earliest sign or symptom of a cold sore.

 
Warnings/precautions

  • Pregnancy Category B
  • Initiate therapy ASAP

 
Adverse Effects

  • Headache
  • Nausea & vomiting

 
Patient Education

  • May take with or without food
  • Initiate therapy ASAP (within 6 hours of outbreak)

 
Valtrex® (valacyclovir)       Available as: 500mg & 1GM tablets
Mechanism: rapidly transformed to acyclovir by first pass metabolism in the gut & liver.
Indication for Use:                           

  • Zoster (shingles):  1GM three times daily for 7 days (begin treatment within 48 hours)
  • Labialis (cold sores): 2 grams twice for 1 day
  • Genital herpes: initial episodes: 1GM twice daily for 7- 10 days. (treat within 48 hours)
  • Recurrent episodes: 500mg twice daily for 3 days or 1GM daily for 5 days
  • Suppression: 500mg daily (if less than 9 outbreaks per year)
  • Suppression: 1GM daily (if more than 9 outbreaks per year)
  • Chronic suppressive antiviral therapy reduces the risk of HSV reactivation and decreases (but may not eliminate) shedding in patients with frequent recurrences
    All treatments should begin as soon as symptoms appear

Warnings/precautions:

  • Photosensitivity
  • Pregnancy category-B

 
Epithelial Keratitis dosing for oral antiviral agents.
http://www.aao.org/clinical-statement/herpes-simplex-virus-keratitis-treatment-guideline

  • Acyclovir (Zovirax®): 400mg 3-5 times daily for 7-10 days OR
  • Valacyclovir (Valtrex®):  500mg twice daily for 7-10 days OR
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Depending upon whether the HSV-1 virus attacks the oral mucosa, or HSV-2 attacks the genital mucosa, the doses for the three antivirals are different.
For Zoster (shingles), caused by a varicella virus, think highest dose for longest duration.  Most important with the treatment of these viral infections, start treatment early, ideally within 48 hours of onset of symptoms.
Didn’t you forget something??  Topical treatment of Herpes infections?
The short answer is no I didn’t.  All of the topical products whether for cold sores, genital herpes or herpes eye infections are expensive and need to be applied frequently, at least 5 times per day.
With the oral dosage forms being available as generics, there is no need whatsoever to prescribe these less than effective and overpriced products.
 
Have a great day on the bench!!

Start Earning CE Now
0.25 ce credits

Depending upon whether the HSV-1 virus attacks the oral mucosa, or HSV-2 attacks the genital mucosa, the doses for the three antivirals are different.
For Zoster (shingles), caused by a varicella virus, think highest dose for longest duration.  Most important with the treatment of these viral infections, start treatment early, ideally within 48 hours of onset of symptoms.
Didn’t you forget something??  Topical treatment of Herpes infections?
The short answer is no I didn’t.  All of the topical products whether for cold sores, genital herpes or herpes eye infections are expensive and need to be applied frequently, at least 5 times per day.
With the oral dosage forms being available as generics, there is no need whatsoever to prescribe these less than effective and overpriced products.
 
Have a great day on the bench!!