Antivirals Commonly Used in Dentistry: Assessment, Analysis, and Associated Dental Management Guidelines
ACYCLOVIR, VALACYCLOVIR, AND FAMCICLOVIR OVERVIEW AND FACTS
Acyclovir and valacyclovir are purine nucleoside analogues and both drugs act against herpes simplex 1 and 2 (cold sores and genital herpes, respectively), varicella zoster (shingles and chicken pox), and the Epstein-Barr virus (infectious mononucleosis).
Neither acyclovir nor valacyclovir cures the viral infection, but they do decrease the symptoms and signs associated with the viral infection. Both drugs can be taken with or without food, and it is best to take the drug around the same time every day. The elderly patient should be given a lower dose of either drug, compared to the normal, healthy patient.
Acyclovir (Zovirax) and Valacyclovir (Valtrex) Mechanism of Action
Both drugs impair viral growth by inhibiting replication of the viral DNA. The virus-infected cells absorb more of the drugs compared to the normal cells. Thus, the active form of the drug is available longer where needed, enhancing the efficacy of the drugs.
Acyclovir (Zovirax) and Valacyclovir (Valtrex) Clearance
Both drugs are excreted mainly by the kidneys, and the dose should be decreased in the presence of renal dysfunction. The dose of acyclovir or valacyclovir should be repeated after hemodialysis.
No dose modification is needed with any form of liver disease.
Acyclovir (Zovirax) and Valacyclovir (Valtrex) Drug Resistance and Side Effects
Resistance can occur with overuse of acyclovir or valacyclovir and it is best to use these drugs short-term and only when needed. Nausea, vomiting, and diarrhea can occur with both drugs.
Acyclovir (Zovirax) Facts
Avoid acyclovir with amphotericin B, bactrim, aspirin NSAIDS, zidovudine (AZT/ Retrovir), or prograf.
- Acyclovir tablet: 400mg/800mg per tablet
- Acyclovir capsule: 200mg/capsule
- Acyclovir suspension: 200mg/5mL: 473mL/bottle
- Acyclovir ointment: 5% cream: 15g tube