Almitrine increases the steady-state hypoxic ventilatory response in hypoxic chronic air-flow obstruction.
Almitrine, a peripheral chemoreceptor agonist, exerts beneficial effects on blood gases in patients with hypoxic chronic air-flow obstruction, but as these patients exhibit poor ventilatory responses to hypoxia, the mechanism for this improvement is not clear. The effect of a 100-mg dose of almitrine given orally on ventilation and the steady-state hypoxic ventilatory response (HVR) were measured in a randomized, double-blind, placebo-controlled manner in 7 patients with severe hypoxic chronic air-flow obstruction. The isocapnic HVR (delta VE/delta SaO2) was calculated from the changes in ventilation and SaO2 from breathing 60% O2 to breathing air with the addition of CO2 to maintain isocapnia (as estimated from a transcutaneous CO2 electrode). Resting ventilation while breathing air and isocapnic HVR were measured before and 3 h after almitrine or placebo. Almitrine caused no significant change in resting ventilation. There was, however, a large increase in HVR after almitrine (almitrine: -1.5 L/min/%SaO2; range, -0.5 to -3.1; control: -0.4; range, -0.3 to -1.3), but no change after placebo. Almitrine is a powerful stimulant of chemosensitivity and of the hypoxic ventilatory response in chronic hypoxemia, with potential benefit to patients with chronic air-flow obstruction in respiratory failure.
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D000368:Aged; D015765:Almitrine; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000032:analysis; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004311:Double-Blind Method; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008173:Lung Diseases, Obstructive / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000494:pharmacology*; D010991:Plethysmography / Q000379:methods; D011897:Random Allocation; D012119:Respiration / Q000187:drug effects*
D000697:Central Nervous System Stimulants; D010879:Piperazines; D002245:Carbon Dioxide; D015765:Almitrine