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Original Investigation
August 2015

Evaluation of the Efficacy, Safety, and Tolerability of 3 Dose Regimens of Topical Sodium Nitrite With Citric Acid in Patients With Anogenital Warts: A Randomized Clinical Trial

Author Affiliations
  • 1Division of Applied Medicine, University of Aberdeen, Foresterhill, Aberdeen, Scotland
  • 2Department of Dermatology, University Medical Centre, Groningen, Groningen, the Netherlands
  • 3Department of Dermatology and Venereology, Medical University of Warsaw, Warsaw, Poland
  • 4Paula-Modersohn-Platz Freiburg, Germany
  • 5University of Exeter Medical School, University of Exeter, St Luke’s Campus, Exeter, England
  • 6Department of Dermatology, Erasmus Medical Centre, Rotterdam, the Netherlands
  • 7Department of Dermatology, Havenziekenhuis, Rotterdam, the Netherlands
JAMA Dermatol. 2015;151(8):854-861. doi:10.1001/jamadermatol.2015.0381

Importance  Anogenital warts are a common disorder associated with significant physical and mental distress and a substantial cause of health care costs.

Objective  To assess the efficacy of the topical application of nitric oxide delivered using acidified nitrite.

Design, Setting, and Participants  A multicenter, randomized, controlled, dose-ranging clinical trial was conducted in European genitourinary medicine clinics between December 20, 2001, and January 14, 2003. Analysis was by intent to treat for all individuals initiating therapy. Participants included male and female volunteers older than 18 years with between 2 and 50 external anogenital warts. A total of 299 individuals from 40 centers were randomized to a control arm and a treatment arm that received 3 doses of acidified nitrite applied topically for 12 weeks with an additional 12 weeks of follow-up, with the final follow-up visit on January 14, 2003.

Interventions  Placebo nitrite cream and placebo citric acid cream were applied twice daily. Active treatment was divided as low dose (sodium nitrite, 3%, with citric acid, 4.5%, creams applied twice daily), middle dose (sodium nitrite, 6%, with citric acid, 9%, creams applied once daily at night, with placebo applied in the morning), and high dose (sodium nitrite, 6%, with citric acid, 9%, creams applied twice daily).

Main Outcomes and Measures  The primary outcome was proportion of patients with complete clinical clearance of target warts; secondary outcomes were reduction in target wart area and safety.

Results  Complete clinical clearance at 12 weeks occurred in 10 of 74 patients (14%; 95% CI, 6%-21%) with placebo; 11 of 72 (15%; 95% CI, 7%-24%) with low-dose treatment; 17 of 74 (23%; 95% CI, 13%-33%) with middle-dose treatment; and 22 of 70 (31%; 95% CI, 21%-42%) with high-dose treatment (P = .01). Reduction in target wart area, time to clearance, and patient and investigator assessments supported the superiority of the high-dose therapy vs placebo. There were no systemic or serious adverse events associated with treatment. However, there was a dose-related increase in itching, pain, edema, and staining of the anogenital skin associated with the active treatment. Overall, 21 patients withdrew from active treatment because of adverse events compared with none using placebo.

Conclusions and Relevance  Use of sodium nitrite, 6%, with citric acid, 9%, twice daily is more effective than placebo in the treatment of anogenital warts. Treatment was associated with local irritant adverse effects.

Trial Registration  clinicaltrials.gov Identifier: NCT02015260