The Use of Noscapine (Narcotine) as an Antitussive Agent

Abstract

and similar compounds is based on a phenanthrene nucleus, whereas Noscapine is an isoquinoline derivative (related to papaverine). It is readily absorbed after oral or parenteral administration, disappears rapidly from the blood stream, and only traces appear in the urine. Its fate is unknown. It has been referred to as the least toxic of the opium alkaloids in mice, rats, and man. Up to 3 grams by mouth have been given to man with only minor side reactions. Chronic toxicity studies did not demonstrate any cumulative effects. No depressant action on respiration or the central nervous system has been observed up to toxic doses; stimulation may appear with higher doses. The effects of Noscapine on the gastrointestinal tract were insignificant. No effects on secretory activity and minimal effects on gastrointestinal movements were reported. Occasionally emesis and constipation were noted only with large doses. No significant analgesc action was observed. Potentiation of morphine analgesia with antagonism to side effects have been reported, but not definitely established. The parenteral use of Noscapine has been limited because of local pain. In experimental cough in animals and man, it was described as effective as codeine. No tolerance to the drug developed. Finally, although no antihistaminic action was found, it did inhibit the “allergic cough” in sensitized guinea pigs exposed to aerosols of specific antigen. It did not, however, prevent anaphylactic shock after injected antigen. In a study centering about the experimental production of cough in normal and asthmatic subjects, small doses of Narcotine (5 and 15 mg.) were demonstrated to have greater anti