PARKE-DAVIS SEEKING BENADRYL Rx-TO-OTC SWITCH FOR ANTIPRURITIC

PARKE-DAVIS SEEKING BENADRYL Rx-TO-OTC SWITCH FOR ANTIPRURITIC use via a petition to amend the monograph for OTC antihistamine drug products. In an Aug. 31 submission to FDA, the firm's counsel (Washington-based Kleinfeld, Kaplan & Becker and Stovall & Spradlin) requested that the allowable indications for oral diphenhydramine be extended to include a claim for the relief of allergic itching. Oral diphenhydramine is currently Category I for symptoms of hay fever and the common cold. In support of the safety and efficacy of oral diphenhydramine as an OTC antipruritic, the submission points to Parke-Davis' approved NDA for Benadryl as a treatment of "uncomplicated allergic skin manifestations of urticaria and angioedema," and inclusion of the ingredient in the OTC antihistamine tentative final monograph (TFM). The submission also notes that switching the allergic itching indication to OTC status does not raise any safety issues related to dosing because the recommended prescription dose (25 mg to 50 mg three to four times daily) is identical to the dose recommended for relief of cold/hay fever symptoms in the antihistamine TFM. The firm is suggesting that the antihistamine final monograph permit oral diphenhydramine products to carry the indication: "For temporary relief of itching associated with hives, minor skin irritations, or rashes due to food or animal allergies, insect bites, inhaled allergens (dust, mold, spores), poison ivy, oak, or sumac, soaps, detergents, cosmetics, and jewelry." In addition to its use as an antihistamine, diphenhydramine has been switched to OTC status for use as a sleep-aid and as an antitussive. Both the antihistamine and nighttime sleep-aid switches were accomplished through the monograph procedures, while the drug's OTC use as an antitussive was approved via a supplement to Parke-Davis' Benadryl NDA. Discussing the firm's reasons for pursuing the switch through the monograph, the submission states: "The expeditious review and approval possible by following [the monograph] route furthers the statutory policy favoring direct public access to safe and effective self-medication. This policy is particularly important for a symptom as prevalent and widespread as itching associated with common minor allergic responses (e.g., insect bites, inhaled allergens, poison ivy, etc.)." To "require an NDA for OTC marketing," the filing continues, "would unduly and unnecessarily delay a clearly desirable result." The filing notes that if the switch is allowed, "the existing warnings [for diphenhydramine] on drowsiness and use in patients with glaucoma, prostatic hypertrophy, and asthma" discussed in the antihistamine TFM would apply to the antipruritic indication. In addition, the firm is recommending that the antihistamine TFM incorporate warnings required "for OTC topical antiprurities concerning discontinuing use and consulting a physician if the condition worsens or symptoms persist for more than seven days."