ARANDOMIZED DOUBLE-BLIND PLACEBOCONTROLLED CLINICAL TRIAL OF TWO STRENGTHS OF TOPICAL ZINC SULFATE SOLUTION AGAINST RECURRENT HERPES SIMPLEX

Background and Objective – Recurrent herpes simplex is one of the most common infections in humans, but there is not yet an effective treatment to prevent recurrence. Topical zinc sulfate 0.5% to 20% was recently used to reduce recurrence of the infection, but the high concentrations caused severe irritation. In this study, the efficacy of topically administered zinc sulfate in reducing the frequency of herpes simplex attacks was assessed. Methods – Sixty-four patients with recurrent herpes simplex referred to educational dermatology centers in Isfahan during 1999 – 2000 were enrolled in a double-blind clinical trial. Patients were randomized to treatment with topical zinc sulfate 0.05% or 0.025% or placebo for 6 months. No other drugs were permitted during the study. Patients were followed for possible side effects. Data analysis was performed using ÷2 (Chi-squared) and SPSS software. Results – There was a statistically significant reduction (60% reduction from pre-treatment number of attacks) in the group receiving zinc sulfate 0.05% (p < 0.01) compared with the groups receiving zinc sulfate 0.025% (25% reduction) and placebo (16% reduction). There was no significant difference between the frequency of recurrence in patients receiving placebo or 0.025% zinc sulfate at the end of 4 months of follow-up. After 6 months, the recurrence rate in patients treated with zinc sulfate 0.05% was much lower than that in the other two groups. Conclusion – Topical zinc sulfate 0.05% was an effective therapeutic modality against recurrent herpes simplex compared with either a lower concentration or placebo.