<prompt> A 70 kg old athlete was posted for surgery, Patient was administered succinylcholine due to unavailability of vecuronium. It was administered in intermittent dosing total 640 mg. During recovery, the patient was not able to respire spontaneously move limbs. What is the explanationPseudocholinesterase deficiency increasing action of syccinylcholinePhase 2 blockade produced by succinylcholineUndiagnosed muscular dystrophy and muscular weaknessMuscular weakness due to fasciculation produced by succinylcholine  <response>: This a case of phase II block, caused by a high dose of succinylcholine.After administration of 7-10 mgkg or 30-60 minutes of exposure to succinylcholine, non-deplarizing dual or phase II block occurs. MillersOption a requires specific mention here because prolonged paralysis with succinylcholine administration may also occur in pseudocholinesterase deficiency. But, this is due to the phase II block.So, Sch can cause phase II block in two conditions:-When Sch is administered in high dosesPatients with atypical or deficient pseudocholinesterase. It these patients it occurs at usual doses as usual amount of Sch is not metabolized. 