Valtrex or valacyclovir
Pharmacokinetics of acyclovir in immunocompromized children with leukopenia and mucositis after chemotherapy: can intravenous acyclovir be substituted by oral valacyclovir?

Soderhall S.

Karolinska Pharmacy, Karolinska Hospital, SE-171 76 Stockholm, Sweden. stygge.staffan swipnet.se

BACKGROUND: The efficacy of oral acyclovir, a purine nucleoside analogue with activity against human herpes viruses, is limited as a result of its low bioavailability. Valacyclovir, the L-valyl ester of acyclovir, has been developed as a pro-drug to improve the bioavailability. The aim of the present study was to compare the pharmacokinetics of acyclovir after intravenous administration and after oral administration of valacyclovir. PROCEDURE: The pharmacokinetics of acyclovir were studied in 18 children aged 1.4-18.1 years (median: 6.9 years; 9 females) after intravenous infusion (1 hr; median dose: 10.5 mg/kg). In 10 of the children the pharmacokinetics of acyclovir were also studied after oral administration of valacyclovir (median dose: 34.1 mg/kg). Quantification of acyclovir in serum was performed by reversed-phase liquid chromatography with fluorometric detection. The pharmacokinetic analysis was performed by pharmacokinetic modelling. RESULTS: The serum concentration versus time curves of acyclovir were described by the two compartment model after intravenous administration and by the one compartment model with a zero- or first-order absorption phase after oral administration of valacyclovir. The bioavailability of acyclovir after oral administration of valacyclovir was 45% (median value; 95% CI: 37-55%). CONCLUSION: It is possible to substitute intravenous acyclovir therapy by oral valacyclovir therapy in children with leukopenia and mucositis after chemotherapy. This finding can at present not be fully implemented in clinical practice, since a commercial pharmaceutical formulation of valacyclovir aimed for children not able to swallow intact tablets is lacking. Crushed valacyclovir tablets have a very unpleasant taste, but can be administered to children through nasogastric tubes. Copyright 2002 Wiley-Liss, Inc.

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Valtrex or valacyclovir
Valacyclovir prevention of cytomegalovirus reactivation after heart transplantation: a randomized trial.

Crisp A.

North West Lung Centre, Wythenshawe Hospital, Manchester, United Kingdom. jegan mater.ie

BACKGROUND: Cytomegalovirus (CMV) is a major cause of serious morbidity following solid organ transplantation via both direct and indirect mechanisms. The aim of this study was to investigate the efficacy and safety of valacyclovir prophylaxis in heart transplant recipients. METHODS:Twenty-seven CMV seropositive adults due to receive a heart transplant were included in a single-center, randomized, double-blind study. Patients were randomized to receive either oral valacyclovir 2000 mg or oral acyclovir 200 mg four times daily starting within 3 days of heart transplant and continuing for 90 days. The primary outcome measure was time to development of CMV antigenemia assessed for 6 months after surgery. Other measures were time to asymptomatic CMV infection, symptomatic CMV infections, and end-organ CMV disease. Patients were monitored for other herpes infections, other opportunistic infections, and acute graft rejection. Safety was assessed by evaluating changes in hematology and clinical chemistry parameters and by the occurrence of adverse events. RESULTS: The median time to CMV antigenemia was 19 days for the acyclovir group compared with 119 days for the valacyclovir group (hazard ratio 0.42; 95% CI, 0.18-0.99; p = 0.049). Similar delays of approximately 100 days were found for CMV infection, symptomatic CMV infection, and CMV disease. There was also a trend for delayed acute rejection, and fewer opportunistic or other herpesvirus infections occurred in the valacyclovir group. Valacyclovir was well tolerated in the study population. CONCLUSION: Oral valacyclovir is a safe and effective mode of prophylaxis of CMV after heart transplantation.

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Valtrex or valacyclovir
Randomized study of valacyclovir as prophylaxis against cytomegalovirus reactivation in recipients of allogeneic bone marrow transplants.

Valacyclovir International Bone Marrow Transplant Study Group.

Department of Haematology, Huddinge University Hospital, Stockholm, Sweden. per.ljungman medhs.ki.se

Oral valacyclovir for cytomegalovirus (CMV) prophylaxis in bone marrow transplantation (BMT) was investigated in a randomized, double-blind, acyclovir-controlled, multicenter clinical trial in recipients of allogeneic BMT who were CMV seropositive (or donor positive) before transplantation and were aged 13 years or older. Patients were randomized before BMT. All initially received intravenous acyclovir (500 mg/m(2)) 3 times daily until day 28 after transplantation or after discharge, then oral valacyclovir (2 g) or acyclovir (800 mg) 4 times daily until week 18 after transplantation. Evidence of CMV infection, CMV disease, and death were documented for 22 weeks. Primary end points were time to CMV infection (detection of CMV in blood, broncho-alveolar lavage) or CMV disease and survival. Preemptive CMV therapy was permitted. Seven hundred twenty-seven patients were evaluable for efficacy. After the administration of intravenous acyclovir, valacyclovir was significantly more effective than oral acyclovir in reducing the incidence of CMV infection. CMV infection or disease developed in 102 (28%) valacyclovir patients, compared with 143 (40%) acyclovir patients (HR, 0.59; 95% CI, 0.46-0.76; P <.0001). Survival did not differ between treatments (76% and 75% in the valacyclovir and acyclovir groups, respectively). The safety of oral valacyclovir was similar to that of high-dose oral acyclovir. Valacyclovir was more effective than acyclovir in preventing CMV reactivation in BMT recipients and showed a similar safety profile. CMV disease incidence was low, and no differences were observed between oral valacyclovir and acyclovir. Survival was similar in each group. Valacyclovir prophylaxis provides a clinically valuable intervention but must be part of an overall strategy for CMV prevention in BMT.

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Valtrex or valacyclovir
Valacyclovir prophylaxis for herpes simplex virus infection or infection recurrence following laser skin resurfacing.

Rachel JD.

Department of Otolaryngology/Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, USA. fps beeson.com

BACKGROUND: The CO2 laser for cutaneous resurfacing has been associated with the reactivation of herpes simplex virus (HSV), causing delayed reepithelialization and scarring. Antiviral agents appear to be effective in reducing reactivation, however, the optimal therapeutic regimen has yet to be clearly defined. OBJECTIVE: To assess the reactivation rates of HSV after CO2 laser resurfacing in patients who received prophylactic valacyclovir for either 10 or 14 days. METHODS: One hundred twenty patients received valacyclovir 500 mg twice a day for either 10 or 14 days starting the day prior to facial laser resurfacing. Serology levels and consecutive Tzank preparations were obtained to determine past exposure to HSV and the presence of virus. RESULTS: No patients in either group developed an HSV infection or had a recurrence. CONCLUSION: These results support the use of valacyclovir in a 10- or 14-day regimen as a preventive agent against HSV outbreaks following facial laser resurfacing.

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Valtrex or valacyclovir
Treatment of sudden sensorineural hearing loss with systemic steroids and valacyclovir.

Witsell DL.

Division of Otolaryngology-Head and Neck Surgery, Department of Surgery, Duke University Medical Center, Durham, NC 27710, USA. tucci001 duke.edu

OBJECTIVE: To determine if the addition of an antiviral medication to systemic steroids improves recovery in the treatment of idiopathic sudden sensorineural hearing loss. STUDY DESIGN: Randomized, double-blind, placebo-controlled prospective multicenter clinical trial. SETTING: The study was administrated from a tertiary care center and clinical research institute; patients were enrolled by otolaryngologists in academic and private practice outpatient settings. PATIENTS: Inclusion criteria included 1) loss of at least 30 dB in 3 contiguous frequencies over <3 days in patients with previous audiometry, 2) marked loss of hearing in patients with prior subjectively normal hearing and no previous audiometry, with contralateral hearing taken as baseline, and 3) patients seen within 10 days of onset of hearing loss. Pretreatment evaluation included audiometry and complete blood cell count, complete blood chemistry, and fluorescent treponemal antibody absorption test. Auditory brainstem-evoked response or magnetic resonance imaging was recommended. INTERVENTION: Patients received prednisone (80 mg/d for 4 d, then tapered over 8 d) with placebo or prednisone with valacyclovir (1 g, 3 times a day for 10 days). MAIN OUTCOME MEASURE: 1) Audiometric assessment at presentation, Week 2, and Week 6; 2) Hearing Screening Inventory questionnaire twice weekly for 6 weeks; and 3) acute Short Form-12 questionnaire at presentation and Week 2. RESULTS: Of 105 subjects enrolled in the study, 84 subjects were evaluable. There were no significant differences between placebo and valacyclovir treatment groups in terms of hearing recovery or symptom recovery on the basis of the Hearing Screening Inventory or Short Form-12 questionnaires. No adverse events were related to the use of valacyclovir. CONCLUSION: Within the paradigm used in the current study, an antiviral medication did not provide more benefit than steroid alone in the treatment of idiopathic sudden sensorineural hearing loss.

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