<prompt> Which of the following local anaesthetic is the shoest acting which aids in obstetric anaesthesia?TetracaineBupivacainePrilocaineChloroprocaine  <response>: Chloroprocaine is a chlorinated derivative of procaine. Its major assets are its rapid onset and sho duration of action and its reduced acute toxicity due to its rapid metabolism plasma t12 25 seconds. Chloroprocaine gained widespread use as an epidural agent in obstetric anesthesia, where its rapid hydrolysis served to minimize risk of systemic toxicity or fetal exposure. Ref: Catterall W.A., Mackie K. 2011. Chapter 20. Local Anesthetics. In B.C. Knollmann Ed, Goodman Gilmans The Pharmacological Basis of Therapeutics, 12e. 