May 13, 2015
Combination Cream Proves Effective in Treating
Genital Warts

Aberdeen, Scotland—Pharmacy customers who get up the nerve to ask about treating anogenital warts deserve a good answer. A new study provides some valuable information pharmacists can use to respond.

The study, published recently in JAMA Dermatology, reports that a high-dose treatment of sodium nitrite, 6%, with citric acid, 9%, creams applied twice daily was more effective than placebo for treating the common sexually transmitted disease.

In more than 90% of cases, the warts are caused by infection with human papillomavirus (HPV) types 6 and 11. Common treatments, including topical therapies and surgical removal, can cause local adverse reactions such as include itching, burning, pain, and erosions, and the warts recur about 30% of the time, according to background information in the article.

In a clinical trial conducted in European genitourinary medicine clinics, researchers from the University of Aberdeen, Scotland, examined the efficacy of a topical application of nitric oxide delivered using acidified nitrite.

In a four-arm trial, 299 patients from 40 centers—males and female adults with between two and 50 external anogenital warts—were assigned to either placebo or three acidified nitrite intervention arms ranging in dose.

Those in the intervention group were treated with either:

• A low dose of sodium nitrite, 3%, with citric acid, 4.5%, creams applied twice daily;
• A middle dose of sodium nitrite, 6%, with citric acid, 9%, creams applied once daily at night with placebo in the morning, or
• A high dose of sodium nitrite, 6% with citric acid, 9% percent, creams applied twice daily.

Study authors note that the sodium nitrite cream was applied first and then the citric acid added because citric acid reacts with nitrite to form the active molecule when mixed (NO, nitric oxide). Participants in the placebo arm applied sodium nitrite placebo with citric acid placebo twice daily.

Complete clinical clearance at 12 weeks was identified in 10 of 74 (14%) of the placebo patient; 11 of 72 (15%) of those receiving low-dose treatment; 17 of 74 (23%) who had middle-dose treatment; and 22 of 70 (31%) getting the high-dose treatment, according to the results.

“Reduction in target wart area, time to clearance, and patient and investigator assessments supported the superiority of the high-dose therapy vs. placebo,” the researchers point out.

At the same time, however, a dose-related increase in itching, pain, edema and staining of the anogenital skin was documented, and 21 participants dropped out of the active group, compared to none in the placebo group, because of the adverse effects.

“Sodium nitrite, 6 percent, with citric acid, 9 percent, twice daily is more effective than placebo in the treatment of anogenital warts,” the study concludes. “Treatment in the present study was associated with local irritant adverse effects. Lower doses were not more efficacious than placebo. For the sensitive anogenital application site, this dose probably represents the optimal one for further evaluation.”
U.S. Pharmacist Social Connect