RICH-VICKS OTC PHENYLTOLOXAMINE ANTIHISTAMINIC SUPERIORITY TO PLACEBO

RICH-VICKS OTC PHENYLTOLOXAMINE ANTIHISTAMINIC SUPERIORITY TO PLACEBO is demonstrated in a double blind efficacy trial in 108 patients with confirmed seasonal allergic rhinitis, the firm said in a recent submission to FDA's OTC Review Division. The firm said that in the study," "phenyltoloxamine citrate at 30 mg was shown to be significantly more effective than placebo in relieving the symptoms of allergic rhinitis. Phenyltoloxamine citrate at 60 mg was also effective though to a lesser degree." Under the study protocol, after baseline symptom scores and nasal air flow measurements were taken, patients were randomized into three groups; phenyltoloxamine 30 mg, phenyltoloxamine 60 mg, or placebo. Patients were treated on a q.i.d. basis, and hourly day time evaluations of symptoms and nasal air flow were made. At night, patients took two doses of medication and recorded their symptoms in a diary. The study lasted for eight days. Rich-Vicks acknowledged that in another study submitted to the OTC division "phenyltoloxamine did not appear to relieve the symptoms of allergic rhinitis." However, the firm maintained that "this study should not be considered conclusive because the study was essentially incomplete." The second study involved 75 patients with confirmed seasonal rhinitis who were randomized into groups receiving either 30 mg. 60 mg, or placebo. Drug administration followed the same schedule as in the first study. Rich-Vicks said that the "findings from this study were not supportive" of phenytoloxamine efficacy. However, the firm asserted that the findings were not supportive "because of several difficulties encountered during the conduct of the study." Rich-Vicks explained that "only two-thirds of the desired populations could be recruited, the study was carried out over two different allergy seasons (spring and fall), and a significant number of patients found difficulty in completing the case records which were quite complicated." In response to a request from FDA, Rich-Vicks submitted copies of the case report forms from the two studies to the agency. The study results, plus a third study from the literature reporting efficacy of the ingredient, were submitted to FDA to support a Category I move for phenyltoloxamine citrate at an adult dose of 30-60 mg every four-six hours.