Effect of almitrine on hypoxic ventilatory drive measured by transient and progressive isocapnic hypoxia in normal men.
1. In a double-blind placebo-controlled study, we have investigated the effect of the peripheral chemoreceptor stimulant drug almitrine bismesylate on hypoxic ventilatory drive (expressed as the slope of the minute ventilation/arterial oxygen saturation relationship in litres min-1+-1) as measured by both progressive isocapnic hypoxia at rest and transient hypoxia (three breaths of 100% N2) during moderate exercise, in seven normal men, to determine if the ventilatory response to the transient hypoxic stimulus is a more specific measure of peripheral chemoreceptor sensitivity to hypoxia. 2. Hypoxic ventilatory drive measured using progressive isocapnic hypoxia ranged from -0.13 to -2.65 litres min-1%-1 after placebo and from -0.20 to -6.48 litres min-1%-1 after almitrine. The response was greater after almitrine in six of the seven subjects, and the difference was significant for the whole group (P less than 0.05). 3. Hypoxic ventilatory drive measured using transient hypoxia ranged from -0.19 to -1.59 litres min-1%-1 after placebo and from -0.09 to -1.62 litres min-1%-1 after almitrine. The response was not consistently greater after almitrine, and the difference was not significant for the group. 4. Difficulties in accurately quantifying a brief rise in minute ventilation after transient hypoxia, particularly in subjects with a low hypoxic ventilatory drive, may have masked small changes in the slope of the minute ventilation/arterial oxygen saturation relationship with this method.(ABSTRACT TRUNCATED AT 250 WORDS)
Airlie
M A
MA
Department of Respiratory Medicine, University of Edinburgh, U.K.
Flenley
D C
DC
Warren
P M
PM
D000328:Adult; D015765:Almitrine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004311:Double-Blind Method; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D005082:Physical Exertion; D012119:Respiration / Q000187:drug effects*
D000697:Central Nervous System Stimulants; D015765:Almitrine