<prompt> Which of the following drugs is hydrolyzed by a plasma esterase that is abnormally low in activity in about 1 in every 2500 humans?EthanolRifampicinCimetidineSuccinylcholine  <response>: SCh is the shoest acting muscle relaxant due to its metabolism by pseudocholinesterase. Some patients contain an atypical pseudocholinesterase which has abnormally low activity and are susceptible to develop apnea with the use of this drug. 