USE OF OXIDASE INHIBITOR WITH DEXTROMETHORPHAN TO TREAT INTRACTABLE COUGHING AND DERMATITIS

摘要

This invention discloses a method for increasing theeffectiveness of dextromethorphan (DM) in treating eithersevere coughing or dermatitis which do not respond to otherdrug treatments. This method involves the administration, to apatient who is an extensive metabolizer of dextromethorphan andwho is suffering from severe coughing or dermatitis, ofdextromethorphan along with a second agent that inhibits theenzymatic activity of debrisoquin hydroxylase (also calledsparteine monooxygenase, cytochrome P450DB, and cytochromeP450-2D6). Quinidine is an especially potent inhibitor ofenzymatic DM oxidation, but it is not well tolerated byeveryone. Other antioxidants which are less potent and bettertolerated by some patients include quinine, yohimbine,fluoxetine, haloperidol, ajmaline, lobeline, and pipamperone.Since people have major variations in their oxidative enzymeactivities, screening tests should be undertaken under thesupervision of a physician to select a preferred antioxidantfor each particular patient. In tests described herein,patients suffering from intractable coughing or dermatitiswhich did not respond adequately to any other safe andnon-addictive drugs reported excellent results and virtuallycomplete elimination of their coughing or dermatitis. Inaddition, the treated patients did not report any adverse sideeffects such as drowsiness, fatigue, or nausea.