[The effects of almitrine bismesylate in chronic obstructive pulmonary disease with CO2 retention]

Ten cases of chronic obstructive pulmonary disease (COPD) were examined before and 2 hours after oral administration of 150 mg of almitrine bismesylate while breathing 31% oxygen. The agent induced a rise in mouth occlusion pressure (P 0.1) from 2.67 +/- 0.64 cmH2O to 3.74 +/- 1.02 cmH2O (P less than 0.01). However the central inspiratory drive and ventilation response to hypercapnia did not change after taking almitrine. VT/Ti increased from 0.32 +/- 0.06 L/sec. to 0.40 +/- 0.08 L/sec. (P less than 0.01) and RR, Ti, Ti/Ttot were not changed, so VT and VE increased from 0.37 +/- 0.10 L to 0.42 +/- 0.16 L (P less than 0.05) and from 7.70 +/- 1.72 L to 8.85 +/- 2.28 L (P less than 0.05) respectively. VA also increased from 3.34 +/- 0.06 L to 4.14 +/- 0.86 L (P less than 0.01). Analysis of blood gases showed a marked increase in PaO2 from 88.70 +/- 16.19 mmHg to 109.10 +/- 25.57 mmHg (P less than 0.05) and a decrease in PaCO2 from 61.73 +/- 12.15 mmHg to 54.01 +/- 10.37 mmHg (P less than 0.05). Our results suggested that almitrine bismesylate could improve the blood gases in COPD patients with CO2 retention as it is a respiratory stimulant which might act through a peripheral mechanism.