The effects of potent analgesics upon vestibular function.

With the introduction of potent synthetic analgesics, it became evident upon clinical evaluation that the ambulatory patient more frequently displayed the signs and symptoms of toxicity than the bed-ridden patient. Thus, the occurrence of dizziness, nausea and vomiting was appreciably increased in the patient who was up and about and who was receiving meperidine and methadon (14). This phenomenon was not readily appreciated in the case of morphine in ambulant patients because this drug is used principally for seriously-ill bed patients and because of its decreased effectiveness when administered by the oral route. However, it had been recognized by many studying the effects of morphine in man that untoward reactions may occur more frequently in the upright position (5). Two possible approaches to the investigation of this problem were considered, the influence of such medications upon cardiovascular dynamics and their possible alterations of vestibular function. Since preliminary investigations in our laboratory failed to reveal any significant aberrations in cardiovascular dynamics with these drugs (6) this study was initiated to determine the effects of potent analgesics upon labyrinthine function.