Interaction between betamethasone and vecuronium.
A possible interaction between betamethasone and vecuronium was examined in 20 rat phrenic nerve-hemidiaphragm preparations. Ten preparations were bathed in a physiological solution with betamethasone 1 mumol litre-1 added and, after a 30-min period were exposed to vecuronium at concentrations of 4, 6, 8 and 10 mumol litre-1 with vecuronium free washings between each exposure. Ten control experiments were performed also using a betamethasone-free bathing solution. In comparison with control, the betamethasone group had significantly (P = 0.0008) less depression of muscle contraction (twitch) force at all concentrations of vecuronium. The calculated ED50 (50% depression of muscle contraction force) was 5.65 mumol litre-1 for controls and 7.39 mumol litre-1 for betamethasone-pretreated preparations. This study confirms our previous clinical observations that an interaction occurs between vecuronium and betamethasone which is characterized by resistance to neuromuscular block.
Parr
S M
SM
Section of Anaesthesia, Wellington School of Medicine, New Zealand.
Robinson
B J
BJ
Rees
D
D
Galletly
D C
DC
D000818:Animals; D001623:Betamethasone / Q000494:pharmacology*; D003864:Depression, Chemical; D003964:Diaphragm / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009924:Organ Culture Techniques; D010791:Phrenic Nerve / Q000187:drug effects*; D051381:Rats; D014673:Vecuronium Bromide / Q000494:pharmacology*
D014673:Vecuronium Bromide; D001623:Betamethasone