title: [Studies of time-course changes in human body balance after ingestion of long-acting hypnotics].
abstract: Falling accidents are a serious nocosomial problem, with balance disorders after the ingestion of hypnotics said to be a cause. Based on the results of animal studies, it was postulated that this problem involves the muscle relaxation that is a pharmacological effect of benzodiazepines (BZP). No reports have, to our knowledge, been made of time-course changes in human body balance after ingestion of hypnotics. Accordingly, we used quazepam (Doral), a long-acting hypnotic considered to show comparatively weak muscle relaxation, to study static balance after drug ingestion in human volunteers. Briefly, informed consent was obtained from 8 healthy adults, then a gait analytic system (Gangas) was used to test static balance after drug ingestion (Mann and Romberg tests). We also measured circulating drug concentration over time. Our results showed that balance disorders occurred after quazepam ingestion with an unstable posture particularly striking. Given the function of quazepam receptors, it is difficult to surmise that balance disorders after drug ingestion were due to the drug's muscle relaxation. We surmised that inhibition from the central nervous system in connection with nerves awakening was involved. We found a strong correlation between the manifestation of balance disorders after drug ingestion and circulating drug concentration.
authors.affiliation: Department of Otorhinolaryngology, Jikei University School of Medicine, Tokyo.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakamura
authors.forename: Masanori
authors.initials: M
authors.lastname: Ishii
authors.forename: Yoji
authors.initials: Y
authors.lastname: Niwa
authors.forename: Momoko
authors.initials: M
authors.lastname: Yamazaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control; D000328:Adult; D001569:Benzodiazepines / Q000009:adverse effects* / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006993:Hypnotics and Sedatives / Q000009:adverse effects* / Q000493:pharmacokinetics; D004856:Postural Balance / Q000187:drug effects; D012678:Sensation Disorders / Q000139:chemically induced*; D013997:Time Factors
chemical_list: D006993:Hypnotics and Sedatives; D001569:Benzodiazepines; C025130:quazepam