NEUROMUSCULAR AND CARDIOVASCULAR EFFECTS OF DOXACURIUM IN CHILDERN ANAESTHETIZED WITH HALOTHANE

The neuromuscular and cardiovascular effects of doxacurium chloride(BW A938U) were evaluated in 27 children (2–12 yr) anaesthetizedwith 1% halothane and nitrous oxide in oxygen. In nine childrenthe incremental technique was used to establish a cumulativedose-response curve by train-of-four stimulation. The remainingchildren received either 30 or 50 µg kg^–1 of thedrug as a single bolus. The median ED₅₀ and ED ₉₅ of doxacuriumin children were 19 and 32 µg kg^–1, respectively.No clinically significant change in heart rate or arterial pressureoccurred. Following doxacurium 30 µg kg^–1 and 50µg kg^–1, recovery to 25% of control occurred in25 (SEM 6) and 44 (3) min, respectively. The recovery index(25–75% of control) was 27 (2) min. The duration of actionof doxacurium is similar to that of tubocurarine and dimethyl-tubocurarinein children. Compared with adults, children seem to requiremore doxacurium (µg kg^–1) to achieve a comparabledegree of neuromuscular depression, and they recover more rapidly. Presented in part at the American Society of AnesthesiologistsAnnual Meeting, October 1987, and the International AnesthesiaResearch Society Meeting, March 1988.