Acyclovir Herpes Medicine

• Generic name: Acyclovir
• Brand/Trade names: Zovirax
• Dosages: Capsules (200 mg); ointment (5%); oral suspension (200 mg per 5-mL spoonful); tablets (400 mg and 800 mg)
• Pharmacologic category: Antiviral Agent
• FDA approved: 1982
• Habit forming? No
• Pregnancy risk factor: B

Acyclovir is a synthetic nucleoside analogue active against herpes viruses. It can insert itself into virus DNA during virus replication. Acyclovir is used to treat genital herpes simplex virus (HSV), herpes labialis (cold sores), herpes zoster (shingles), HSV encephalitis, neonatal HSV, mucocutaneous HSV in immunocompromised patients, varicella-zoster (chickenpox).

This medication does not cure a herpes infection but may relieve the symptoms of viral infection and shorten the duration of an outbreak.

The most frequent adverse events are nausea, vomiting, diarrhea and headche.

• Elimination half-life: 2.5 to 3.3 hr
• Metabolism: Converted by viral enzymes to acyclovir monophosphate, and further converted to diphosphate then triphosphate (active form) by cellular enzymes
• Excretion: Urine (62% to 90% as unchanged drug and metabolite)

• suppresses asymptomatic viral shedding [9]
• excellent safety profile [13]
• well-tolerated by most patients
• high efficacy [5]
• can reduce asymptomatic viral shedding by 80%

• requires frequent dosing regimen
• does not cure the viral infection

• Posttransplantation cytomegalovirus (CMV) infection [2-3]
• Posttransplantation HSV infection [11, 12]
• Ocular herpes simplex virus infection [4]
• Infectious mononucleosis [6, 7]
• Herpes zoster ophthalmicus [8]
• Varicella pneumonia [10]

Acyclovir prevents the growth and multiplication of the herpes virus.

Acyclovir is selectively phosphorylated only within virus-infected cells by viral thymidine kinase (TK). Further phosphorylation by cellular enzymes leads to the production of acyclovir triphosphate, which compete with the natural nucleotide, dGTP, resulting in the selective inhibition of viral DNA polymerase. Incorporation of the analogue triphosphate into the growing DNA chain prevents continued extension of the DNA chain.

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• 1. U.S. Food and Drug Administration. Zovirax (Acyclovir) U.S. Prescribing Information. Available at (PDF format): Prescribing Information
• 2. Flechner SM, Avery RK, Fisher R, Mastroianni BA, Papajcik DA, O'Malley KJ, Goormastic M, Goldfarb DA, Modlin CS, Novick AC. A randomized prospective controlled trial of oral acyclovir versus oral ganciclovir for cytomegalovirus prophylaxis in high-risk kidney transplant recipients. Transplantation. 1998 Dec 27;66(12):1682-8.
• 3. Winston DJ, Wirin D, Shaked A, Busuttil RW. Randomised comparison of ganciclovir and high-dose acyclovir for long-term cytomegalovirus prophylaxis in liver-transplant recipients. Lancet. 1995 Jul 8;346(8967):69-74.
• 4. Uchoa UB, Rezende RA, Carrasco MA, Rapuano CJ, Laibson PR, Cohen EJ. Long-term acyclovir use to prevent recurrent ocular herpes simplex virus infection. Arch Ophthalmol. 2003 Dec;121(12):1702-4.
• 5. Tyring SK, Douglas JM, Corey L, Spruance SL, Esmann J. A randomized, placebo-controlled comparison of oral valacyclovir and acyclovir in immunocompetent patients with recurrent genital herpes infections. The Valaciclovir International Study Group. Arch Dermatol. 1998 Feb;134(2):185-91.
• 6. Andersson J, Britton S, Ernberg I, Andersson U, Henle W, Sko"ldenberg B, Tisell A. Effect of acyclovir on infectious mononucleosis: a double-blind, placebo-controlled study. J Infect Dis. 1986 Feb;153(2):283-90.
• 7. Ernberg I, Andersson J. Acyclovir efficiently inhibits oropharyngeal excretion of Epstein-Barr virus in patients with acute infectious mononucleosis. J Gen Virol. 1986 Oct;67 ( Pt 10):2267-72.
• 8. Hoang-Xuan T, Bu"chi ER, Herbort CP, Denis J, Frot P, The'nault S, Pouliquen Y. Oral acyclovir for herpes zoster ophthalmicus. Ophthalmology. 1992 Jul;99(7):1062-70; discussion 1070-1.
• 9. Wald A, Zeh J, Barnum G, Davis LG, Corey L. Suppression of subclinical shedding of herpes simplex virus type 2 with acyclovir. Annals Internal Medicine. 1996 Jan 1;124(1 Pt 1):8-15
• 10. Smego RA, Asperilla MO. Use of acyclovir for varicella pneumonia during pregnancy. Obstet Gynecol. 1991 Dec;78(6):1112-6.
• 11. Gluckman E, Lotsberg J, Devergie A, Zhao XM, Melo R, Gomez-Morales M, Mazeron MC, Perol Y. Oral acyclovir prophylactic treatment of herpes simplex infection after bone marrow transplantation. J Antimicrob Chemother. 1983 Sep;12 Suppl B:161-7
• 12. Seale L, Jones CJ, Kathpalia S, Jackson GG, Mozes M, Maddux MS, Packham D. Prevention of herpesvirus infections in renal allograft recipients by low-dose oral acyclovir. JAMA. 1985 Dec 27;254(24):3435-8.
• 13. Girard M. Safety of acyclovir in general practice: a review of the literature. Pharmacoepidemiol Drug Saf. 1996 Sep;5(5):325-32.

Last modified: April, 2010