title: The quinoxaline derivative caroverine in the treatment of sensorineural smell disorders: a proof-of-concept study.
abstract: The treatment of non-conductive olfactory disorders is to a large extent an unsolved problem. This proof-of-concept study focused on possible effects of the N-methyl-D-aspartate (NMDA) antagonist caroverine. Potential mechanisms for the hypothesized effect included reduced feedback inhibition in the olfactory bulb as a consequence of NMDA antagonistic actions and antagonism of an excitotoxic action of glutamate. A total of 77 consecutive patients with non-conductive olfactory disorders were included in the study. Fifty-one patients received caroverine for 4 weeks (120 mg/day); 26 controls matched for age, gender and duration of olfactory loss were treated with zinc sulfate for the same length of time (400 mg/day). Olfactory sensitivity was evaluated before and after treatment. Testing included assessment of n-butanol odor threshold and odor identification. When compared to baseline, treatment with caroverine improved both odor thresholds (p = 0.005) and odor identification (p = 0.042) in anosmic patients. In hyposmic patients it significantly improved odor identification ability (p = 0.041). In contrast, zinc sulfate had no significant effect on olfactory function. These results indicate that caroverine appears to be effective for the treatment of non-conductive smell disorders.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, University of Vienna, Vienna, Austria. christian.quint@univie.ac.at
authors.forename: Christian
authors.initials: C
authors.lastname: Quint
authors.forename: Andreas F P
authors.initials: AF
authors.lastname: Temmel
authors.forename: Thomas
authors.initials: T
authors.lastname: Hummel
authors.forename: Klaus
authors.initials: K
authors.lastname: Ehrenberger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016202:N-Methylaspartate / Q000037:antagonists & inhibitors*; D000857:Olfaction Disorders / Q000175:diagnosis / Q000188:drug therapy* / Q000209:etiology; D011810:Quinoxalines / Q000627:therapeutic use*; D012684:Sensory Thresholds / Q000187:drug effects; D012903:Smell / Q000187:drug effects; D019287:Zinc Sulfate / Q000627:therapeutic use
chemical_list: D011810:Quinoxalines; D016202:N-Methylaspartate; D019287:Zinc Sulfate; C000957:caroverine