Catephen ointment contains 10% green trea (Camellia sinensis) leaf extract, corresponding to 55–72mg epigallocatechin gallate per gram.
Green tea leaf extract inhibits the growth of activated keratinocytes and has local antioxidant effects; however, its mechanism of action in the treatment of genital warts is unknown.
Three times daily
A 0.5cm strand of Catephen should be squeezed from the tube and applied to all external genital and anal warts three times daily for up to 16 weeks. If complete clearance of warts occurs before this time, treatment should stop. Even if new warts appear during treatment, the maximum 16-week recommendation should not be exceeded.
Female patients with warts in the vulvar region and uncircumcised males should apply the ointment with caution. Patients should be made aware that Catephen may weaken condoms and vaginal diaphragms and advised to wash off any ointment before sexual activity.
Complete clearanceSafety and efficacy of the ointment were assessed in two randomised, double-blind pivotal phase III studies in immunocompetent patients (n=502 and n=503).
Pooled analysis showed that treatment with the 10% green tea leaf extract applied three times daily for up to 16 weeks was significantly more effective than vehicle placebo in the treatment of external genital and perianal warts, as measured by rates of complete visual clearance of all warts (53.6% vs 35.4%, p<0.001). Active treatment was associated with a two-fold higher likelihood of complete wart clearance (odds ratio 2.10, 95% CI 1.49–2.98).
The difference in clearance rates reached significance at 6 weeks and the overall time to complete clearance was significantly shorter with active treatment than placebo (p<0.01).
Partial (at least 50%) clearance was observed in 76.0% of patients treated with the green tea leaf ointment compared with 52.2% of those using placebo.
Recurrence of warts in patients who achieved complete clearance did not differ significantly between the active treatment and placebo groups, occurring in 6.5% and 5.8% of patients, respectively.
The most commonly reported adverse effects of the green tea leaf ointment are local application site reactions, including pain, pruritus and oedema. Mild skin reactions should not lead to discontinuation of the product.