TABLE 1

Characteristics before each randomised intervention treadmill test in 17 patients with moderate to severe chronic obstructive pulmonary disease

Intervention arm
Central and peripheral endogenous endorphins (normal saline)Central endogenous endorphins only (methylnaltrexone)No endogenous endorphins (naloxone)
Subjects n171616
FEV1
 Baseline
  Litres1.62±0.541.67±0.611.59±0.57
  % pred53.95±17.6656.16±18.0552.94±17.82
 Post-bronchodilator
  Litres1.83±0.721.76±0.671.69±0.59
  % pred56.28±18.1656.58±16.9356.53±18.27
Mean FVC
 Litres2.95±0.623.10±0.712.98±0.61
 % pred72.95±11.7777.107±11.1773.89±11.34
Post-bronchodilator FEV1/FVC0.55±0.160.56±0.180.55±0.17

Data are presented as n or mean±sd. FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity.