Detailed Drug Information:

DRUG CLASS AND MECHANISM: Viral illnesses differ from bacterial infections in that viruses are not living organisms, but rather take over living cells and reproduce themselves, often at the expense of the host cell. Acyclovir is an antiviral drug which acts against the Herpes viruses, including herpes simplex 1 and 2 (cold sores and genital herpes), varicella-zoster (shingles and chicken pox), and the Epstein-Barr virus (mononucleosis). Acyclovir inhibits the replication of viral DNA needed to reproduce itself. Virally infected cells absorb more acyclovir than normal cells and convert more of it to an active form which prolongs its antiviral activity where it is most needed.

PREPARATIONS: Capsules (200 mg); Tablets (400mg, 800mg); Ointment 5% (15gm).

STORAGE: Acyclovir should be stored at room temperature in a tight container.

PRESCRIBED FOR: Oral acyclovir is used to treat initial genital herpes infections and to treat patients with recurrent (6 episodes per year) severe genital herpes. Acyclovir reduces the pain and the number of lesions in the initial case, and decreases the frequency and severity in those with recurrent infections. In the treatment of shingles, acyclovir reduces pain, shortens the healing time, and limits the spread of virus and the formation of new lesions. Acyclovir can be used to treat chicken pox and acts to reduce healing time, limit the number of lesions, and reduce fever if used within the first 24 hours after the onset of the disease. Acyclovir ointment is used topically to treat initial genital herpes where it has been shown to decrease pain, reduce healing time, and limit the spread of the infection.

DOSING: Acyclovir may be taken with or without food. Acyclovir is excreted mainly by the kidney and dosages need to be reduced in patients with kidney dysfunction.

DRUG INTERACTIONS: Genital herpes is a sexually transmitted disease and patients should avoid intercourse when they have visible lesions. Resistance to acyclovir can develop, especially with overuse. Therefore, acyclovir should be used only for severe cases and only as long as needed. Long-term suppression for recurrent genital herpes should include periodic re-evaluations and trials without the drug or intermittent short-term treatments.

SIDE EFFECTS: Rare side effects in patients treated short-term with acyclovir are nausea, vomiting, and headache. Long-term treatment has the additional potential for rash and diarrhea.