Compounds such as 5-chloronicotine, 5-fluoronornicotine, anabaseine, 5-fluoroanabaseine, 2-acetoxymethylquinuclidine or 2-(3-pyridyl)-quinuclidine are useful as locally acting and highly selective muscle relaxants. Each compound, when administered intravenously, acts to bind to musculoskeletal nicotinic receptor sites in a reversible manner causing transient depolarization, and hence provides for reversible muscle relaxation to a patient during anesthesia.