<prompt> Succinylcholine is used with caution in all exceptMythenia gravisBurnsCrush injuryTachycardia  <response>: Sch is the only muscle relaxant that causes vagal stimulation and causes bradycardia attenuates tachycardia and hypeension In burns, crush injury and myasthenia gravis can cause severe hyperkalemia. Ref: Morgan 4the p 214 