[Naloxone--a clinical study on dosage (author's transl)].

In 50 Patients (group I) anaesthetized with neuroleptanalgesia and in 20 patients (group II) anaesthetized with moderate doses of fentanyl given to supplement nitrous oxide - halothane anaesthesia the postoperative respiratory depression was antagonized with naloxone. Each patient was carefully titrated with small increments of naloxone (40 microgram) given in 1-2 minute intervals. A reversal of the narcotic induced respiratory depression was taken for granted, when respiratory rate exceeded 12/min, tidal volume and blood gas analysis showed normal values. The results demonstrated a correlation between the need for naloxone and the time interval from the last administration of fentanyl to the completion of the operation and the fentanyl consumption per hour. When the interval was less than 1 hour more than 90% of the patients required postsurgical naloxone for respiratory inadequacy. The mean naloxone dose was 20 to 30% of the fentanyl dose given per hour: 1,2 microgram/kg naloxone reversed 4,9 microgram/kg.h fentanyl (group I) and 0,6 microgram/kg naloxone reversed 2,9 microgram/kg.h fentanyl (group II) respectively. To prevent renarcotization it is recommended to administer naloxone i.m. 30 to 45 min after the last naloxone-injection using the total i.v. dose.