What are actions and therapeutic uses of non-depolarizing blcokers?

1-Benzylisoquinolinium compounds (Curare, Mivacurium, Atracurium release histamine lead to fall in BP, flushing and bronchoconstriction) Used as adjuvant of anesthesia to relax skeletal muscles, facilitate intubation in surgery, orally ineffective due to quaternary amines, penetrate membranes poorly can't cross BBB, many not metabolized excreted unchanged in urine Curare and miva. Atracurium degraded in plasma by ester hydrolysis, releases histamine provokes seizures. Cisatracurium same as atra but less likely to get effects) 2-Aminosteroid drugs (Vecuronium and Recuronium deacetylated in liver, clearance may be prolonged in pt with hepatic disease, excreted unchanged in bile, choice depends on onset of action and duration of muscle relaxation