DOSE-RESPONSE RELATIONSHIP AND TIME COURSE OF ACTION OF ORG 9426 - A NEW MUSCLE-RELAXANT OF INTERMEDIATE DURATION EVALUATED UNDER VARIOUS ANESTHETIC TECHNIQUES

The dose‐response relationship of Org 9426, its time course of action and the reversibility of the residual block by neostigmine have been investigated in 100 patients undergoing various anaesthetic techniques. The dose‐response was measured immediately following induction of anaesthesia. Doses of Org 9426, required for 50% and 90% depression of the twitch height, were 202 and 328 μg.kg−1, respectively. The clinical duration of the maintenance doses, 150 μg.kg−1, ranged from 9.5 to 13.4 min and from 12.8 to 18.9 min for the first and fifth maintenance doses, respectively. Spontaneous recovery indices (25%‐75%) were between 9.5 and 16.7 min; neostigmine methylsulphate administered at 25% recovery of the twitch height promptly reversed the residual block. No side effects were observed. The extent of the influence of the anaesthetic on the time course of Org 9426 appears to be fractional considering the variation of the time course within the separate groups. Copyright © 1991, Wiley Blackwell. All rights reserved