RT Journal Article SR Electronic T1 THE SEPARATE AND COMBINED RESPIRATORY EFFECTS OF CHLORPROMAZINE AND MEPERIDINE IN NORMAL MEN CONTROLLED AT 46 mm Hg ALVEOLAR pCO2 JF Journal of Pharmacology and Experimental Therapeutics JO J Pharmacol Exp Ther FD American Society for Pharmacology and Experimental Therapeutics SP 381 OP 393 VO 131 IS 3 A1 Lambertsen, C. J. A1 Wendel, H. A1 Longenhagen, J. B. YR 1961 UL http://jpet.aspetjournals.org/content/131/3/381.abstract AB A method for artificially controlling alveolar pCO2 was used to study the time course of changes in respiratory rate, depth and minute volume after intramuscular administration of physiological saline solution (2 ml), chlorpromazine hydrochloride (25 mg/70 kg), meperidine hydrochloride (100 mg/70 kg) and of meperidine together with chlorpromazine in the stated doses. The method employed provided magnification of drug-induced respiratory alterations by preventing the physiological readjustments in alveolar pCO2 normally associated with changes in alveolar ventilation. The results obtained indicated (a) the time course of a consistent and prominent respiratory depression by meperidine, (b) that chlorpromazine alone produces no consistent respiratory depression but that it may tend to improve tolerance to elevated pCO2, and (c) that administration of chlorpromazine with meperidine causes respiratory depression greater in degree and duration than produced by meperidine alone. The data obtained are discussed with regard to mechanisms of the observed chlorpromazine-meperidine interaction.