Imiquimod (Aldara)
This immunomodulator is FDA-approved for topical treatment of external and perianal genital warts, which are caused by papillomavirus. Gradual clearance of warts occurs in about 50% of patients over an average of 8 to 10 weeks. Recurrences are less common than after ablative therapies. Imiquimod is also effective for a high percentage of patients with too many actinic keratoses to be treated with liquid nitrogen.