Acyclovir

U.S. Brand Names: Zovirax®

Use: Used to treat herpes zoster.

Contraindications: Do not use this drug if you have had an allergic reaction to acyclovir or any of its components in the past.

Warnings/Precautions: This drug is for oral ingestion only. Patients on Zovirax® must begin treatment within 72 hours of the onset of the shingles rash. The drug is most useful if it is started within the first 48 hours.

Pregnancy Category: C; this drug can enter breast milk so use with caution if nursing..

Adverse Reactions:

• General: Fever, headache, pain, peripheral edema, and rarely, anaphylaxis
  
• Nervous: Confusion, dizziness, hallucinations, paresthesia, somnolence (These symptoms may be marked, especially in older adults.)
  
• Digestive: Diarrhea, elevated liver function tests, gastrointestinal distress, nausea
  
• Hemic and Lymphatic: Leukopenia, lymphadenopathy
  
• Miscellaneous: Malaise, nausea, headache, vomiting, diarrhea, constipation
  
• Musculoskeletal: Myalgia
  
• Skin: Alopecia, pruritus, rash, urticaria
  
• Special Senses: Visual abnormalities
  
• Urogenital: Elevated creatinine
  
  
  

Famciclovir

U.S. Brand Names: Famvir®

Use: Treatment of acute herpes zoster

Pregnancy Risk Factor and Implications: B; Should be used during pregnancy only if the benefits outweigh the risks. It is not known whether or not it is excreted in human breast milk.

Adverse Reactions:

Note: You must begin treatment with Famvir at least 72 hours after the onset of the rash.

• Nervous System: Headache, paresthesia, migraine
  
• Gastrointestinal: Nausea, diarrhea, vomiting, flatulence, abdominal pain
  
• Body as a whole: Fatigue
  
• Skin and Appendages: Pruritus, rash
  
• Other: Urticaria, hallucinations, confusion (including delirium, disorientation, confusional state)
  

Contraindications: Famvir should not be taken by patients with a known hypersensitivity to the product, its components, and to Denavir (penciclovir cream).

Warnings/Precautions: The efficacy of Famvir has not been established for ophthalmic zoster, disseminated zoster or in immunocompromised patients with herpes zoster. In patients with underlying renal disease who have received inappropriately high doses of Famvir for their level of renal function, acute renal failure has been reported.

Valaciclovir

U.S. Brand Names: Valtrex®

Use: An antiviral agent used to treat herpes zoster (shingles) infection. It is not a cure but will help the sores heal faster and relieve the pain or discomfort of shingles.

Warnings/Precautions: Let your doctor know if you have dehydration, kidney disease, an unusual or allergic reaction to valacyclovir, acyclovir, other medicines, foods, dyes, or preservatives, or if you are pregnant or trying to get pregnant or are breast-feeding.

Adverse Reactions: Note: This drug works best when taken within the first 72 hours of the infection. Begin treatment as soon as possible after the first signs of infection. Possible side effects include increased thirst, reduced amount of urine passed, stomach pain, unusual weakness or tiredness, constipation, headache, loss of appetite, nausea, and vomiting.