<prompt> Phase II block is seen inHalothaneEtherD-tubocurareSuxamethonium  <response>: Ans. is d i.e. . Suxamethonium Suxamethonium causes Biphasic Block, with dose more than 500mg. Phase I block - Features of classical depolarization block Phase II block - Results from desensitization of receptor to acetylcholine and resembles competitive block and partially antagonized by anticholinesterase.Other frequently asked facts about SuccinylcholineIt is a non-competitive muscle relaxant and has overall shortest duration of action dt rapid hydrolysis by Pseudocholinesterase.It causes malignant hyperthermia.It increases muscle tone and causes muscle rigidity.It causes hyperkalemia in ParaplegiaTetanusBumIt increases intraocular pressure and intra-abdominal pressure. 