Abstract
Levorphan is a severe respiratory depressant. Quantitatively it lowers the sensitivity of the respiratory center to CO2 to about one half control. The threshold (apnea point) to CO2 is raised about 4 mm. Hg. Levallorphan alone is also a respiratory depressant though it lowers the sensitivity to CO2 less than levorphan and has no effect on threshold. When these two drugs are given together, ventilation is improved over that with either alone but is still less than control. Stimulus-response curves with subjects under the combination reveal that the sensitivity is restored to control value, but that the threshold remains at the same level as when under levorphan alone. The protective action of levallorphan was most apparent with high alveolar CO2 tensions in these experiments.
Footnotes
- Received October 9, 1954.
- © 1955, by The Williams & Wilkins Company
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