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• Recurrent genital herpes: The study has demonstrated that valaciclovir 500 mg twice daily is equivalent in efficacy to aciclovir 200 mg five times daily as episodic treatment of recurrent genital HSV infection. Valaciclovir maintains the established efficacy and safety of aciclovir but offers a much more convenient twice daily dosing regimen. 1
• First-episode genital herpes: Twice-daily valaciclovir is as effective and well tolerated in the treatment of first-episode genital herpes as five-times-daily acyclovir. Valaciclovir provides a useful alternative to acyclovir with the advantage of a more convenient dosing regimen and the potential for improved compliance.2
• Suppression of HSV shedding: Although the suppression of viral replication is not complete, valacyclovir and acyclovir are highly effective in suppressing the frequency and quantity of genital HSV shedding. No significant differences in frequency and quantity of HSV were detected by polymerase chain reaction (PCR) between the valacyclovir and acyclovir. 3
• Herpes zoster: The study showed that valaciclovir significantly accelerate the resolution of herpes zoster-associated pain compared with acyclovir. In the management of herpes zoster valaciclovir is superior to acyclovir.5
• Post-transplantation cytomegalovirus prophylaxis: Valacyclovir appears to be more effective than acyclovir in preventing CMV reactivation in bone marrow transplant recipients. 4

• Herpes zoster: Acyclovir and famciclovir have comparable efficacy and similar adverse effect profile.
  In the clinical study there was no significant differences between the four treatment regiments (famciclovir 750 mg once daily, 500 mg twice daily and 250 mg daily, and aciclovir 800 mg five times daily) with respect to times to full crusting; loss of vesicles, ulcers and crusts; cessation of new lesion formation; a 50% reduction in the area of affected skin; and the loss of acute pain. 6
  The pharmacokinetics of famciclovir allow a more convenient dosing schedule than the schedule used with acyclovir.

• Herpes labialis (cold sores): In comparative model the efficacy of penciclovir cream was greater than acyclovir cream. 7
• Genital herpes: The results of the study showed that there is no significant differences in clinical efficacy between penciclovir 1% cream and acyclovir 3% cream with respect to clinical cure rate, times to healing, resolution of all symptoms, absence of blisters, cessation of new blisters, crusting, and loss of crust. However a significantly shorter time to crusting was found with penciclovir when compared with acyclovir. Adverse experience was was comparable with two medications. 8

• Acyclovir (Zovirax) Medical Facts

• 1. Bodsworth NJ, Crooks RJ, Borelli S, Vejlsgaard G, Paavonen J, Worm AM, Uexkull N, Esmann J, Strand A, Ingamells AJ, Gibb A. Valaciclovir versus aciclovir in patient initiated treatment of recurrent genital herpes: a randomised, double blind clinical trial. International Valaciclovir HSV Study Group. Genitourin Med. 1997 Apr;73(2):110-6. PubMed
• 2. Fife KH, Barbarash RA, Rudolph T, Degregorio B, Roth R. Valaciclovir versus acyclovir in the treatment of first-episode genital herpes infection. Results of an international, multicenter, double-blind, randomized clinical trial. The Valaciclovir International Herpes Simplex Virus Study Group. Sex Transm Dis. 1997 Sep;24(8):481-6. PubMed
• 3. Gupta R, Wald A, Krantz E, Selke S, Warren T, Vargas-Cortes M, Miller G, Corey L. Valacyclovir and acyclovir for suppression of shedding of herpes simplex virus in the genital tract. J Infect Dis. 2004 Oct 15;190(8):1374-81. Epub 2004 Sep 20. PubMed
• 4. Ljungman P, de La Camara R, Milpied N, Volin L, Russell CA, Crisp A, Webster A; Valacyclovir International Bone Marrow Transplant Study Group. Randomized study of valacyclovir as prophylaxis against cytomegalovirus reactivation in recipients of allogeneic bone marrow transplants. Blood. 2002 Apr 15;99(8):3050-6. PubMed
• 5. Lin WR, Lin HH, Lee SS, Tsai HC, Huang CK, Wann SR, Chen YS, Chiang SC, Yen MY, Liu YC. Comparative study of the efficacy and safety of valaciclovir versus acyclovir in the treatment of herpes zoster. J Microbiol Immunol Infect. 2001 Jun;34(2):138-42. PubMed
• 6. Shafran SD, Tyring SK, Ashton R, Decroix J, Forszpaniak C, Wade A, Paulet C, Candaele D. Once, twice, or three times daily famciclovir compared with aciclovir for the oral treatment of herpes zoster in immunocompetent adults: a randomized, multicenter, double-blind clinical trial. J Clin Virol. 2004 Apr;29(4):248-53. PubMed
• 7. McKeough MB, Spruance SL. Comparison of new topical treatments for herpes labialis: efficacy of penciclovir cream, acyclovir cream, and n-docosanol cream against experimental cutaneous herpes simplex virus type 1 infection. Arch Dermatol. 2001 Sep;137(9):1153-8. PubMed
• 8. Chen XS, Han GZ, Guo ZP, Lu NZ, Chen J, Wang JB; Penciclovir Multicenter Genital Herpes Clinical Study Group. A comparison of topical application of penciclovir 1% cream with acyclovir 3% cream for treatment of genital herpes: a randomized, double-blind, multicentre trial. Int J STD AIDS. 2000 Sep;11(9):568-73. PubMed