title: Prevention of late fentanyl-induced respiratory depression after the injection of opiate antagonists naltrexone and S-20682: comparison with naloxone.
abstract: Compared with naloxone, two opiate antagonists (naltrexone and S-20682) were tested in the intact dog in order to reverse respiratory depression, induced by fentanyl 50 micrograms kg-1 i.v. Respiratory rate and arterial blood-gases were measured at 5, 30, 60, 120, 180 and 240 min after the additional i.v. injection of the antagonist (1 microgram kg-1). Only S-20682, but not naloxone or naltrexone, prevented late (240 min) fentanyl-induced depression of respiratory drive. A late respiratory depression coincided with an increase in amplitudes and a reduction of frequency in electrical cortical activity (EEG). Naltrexone exhibited an antagonistic effect of duration twice (60 min) that of naloxone.
mesh_terms: D000818:Animals; D002245:Carbon Dioxide / Q000097:blood; D003864:Depression, Chemical; D004285:Dogs; D004569:Electroencephalography; D005283:Fentanyl / Q000037:antagonists & inhibitors*; D009019:Morphinans / Q000031:analogs & derivatives / Q000494:pharmacology*; D009270:Naloxone / Q000031:analogs & derivatives* / Q000494:pharmacology*; D009271:Naltrexone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D010100:Oxygen / Q000097:blood; D010313:Partial Pressure; D012119:Respiration / Q000187:drug effects*; D013997:Time Factors
chemical_list: C022915:20682-S; D009019:Morphinans; D009292:Narcotic Antagonists; D002245:Carbon Dioxide; D009270:Naloxone; D009271:Naltrexone; D010100:Oxygen; D005283:Fentanyl