DrugsActingonUterineSmoothMuscleCase128yearsoldfemale,pregnant33weeks,abdominalpain1day.Beganparoxysmalabdominalpainandsorenessofwaistyesterdayfollowinganoverwork.Nocolporrhagia(陰道出血)wasobserved.Obstetricexaminationfoundregularuterinecontraction,cervicalcanal(宮頸管)disappeared,fetalHR148/min,noruptureofmembrane.After8hourstocolytic(保胎)treatmentwithmagnesiumsulfatei.vdrop,camebloodyvaginalfluidandcervixopened5cm,thenchangedtohelpvaginaldelivery.Afterlabor,strongvaginalbleedingoccurredduetopooruteruscontraction,sooxytocin20Uwasi.vdropwith100ml5%glucoseandceasedbleeding.§1Uterus(子宮)Stimulantsoxytocin（縮宮素）pituitrin（垂體后葉素）ergots（麥角類）prostaglandins（前列腺素）Uterinestimulants(uterotonics)aremedicationsthatcause,orincreasethefrequencyandintensityof,uterinecontractions.

Thesedrugsareusedtoinduce(start)oraugment(stimulate)labor（生產）,facilitateuterinecontractionsfollowingamiscarriage（流產）,induceabortion,orreducehemorrhagefollowingchildbirthorabortion.Oxytocin（縮宮素，催產素）A9aminoacidspeptide.StimulatesboththefrequencyandforceofuterinecontractionsPharmacologicaleffectsOnuterine:Smalldose(2~5U)inducerhythmiccontractionfromtheuterinebottom,butrelaxcervix;highdose(5~10U)causesustainedtetaniccontraction.Alsocausecontractionofmyoepithelialcellssurroundingmammaryalveoli,leadstomilkejectionEffectsarehighlydependentonestrogen,whichcanincreaseoxytocinreceptorsintheuterinesmoothmuscle.ProgesteroneantagonizesthestimulanteffectofoxytocinClinicalusesHastenparturition（分娩）---usedintheaugmentationofexistingcontractionstoincreasestrengthandfrequencywhenlaborisnotprogressingwell.odinopoeia（引產）---usedtoinduce,orbegin,laborincertaincircumstanceswhenthemotherhasnotbegunlabornaturally.postpartumhemorrhage（產后出血）,causedbyuterineatony（無力）oruterinemalreduction（恢復不良）afterlabor,increaseuterinecontractionsandminimizebleedingAttention:ThedoseNocontraindicationsexistAntidiuresiseffectsinhighdosePituitrin（垂體后葉素）Includeoxytocin&vasopressinErgotalkaloid(麥角生物堿)Ergotsareproducedbyafungusthatformsprimarilyonryegrain（黑麥）.Ergometrine(麥角新堿)---stimulateuterine,usedinpostpartumhemorrhageoruterineatony(子宮收縮無力)oruterinemalreduction(縮復不良)Ergotamine(麥角胺)---vasoconstriction,usedinmigraine(偏頭痛)ProstaglandinsProstaglandinsplayamajorroleinthestimulationofuterinecontractionsthatbeginthelaborprocess.（蓖麻油炒雞蛋）OnefunctionofPGsistopromotecervicaleffacement（宮頸松軟）anddilationduringlabor.OxytocinplaysaroleinstimulatingthereleaseofPGs.Infectionstimulatestheirrelease,also,whichappearstobeafactorintheinitiationofupto30%ofcasesofpretermlabor（早產）.UterusissensitivetoPGE1,PGE2,andPGF2alpha§2UterusinhibitorsUterusinhibitors（Tocolytics，安胎藥）aremedicationsusedtosuppresspremature（早產）.Theyaregivenwhendeliverywouldresultinprematurebirth.Thetherapyalsobuystimefortheadministrationofbetamethasone（倍他米松）,aglucocorticoiddrugwhichgreatlyacceleratesfetallungmaturity,buttakesonetotwodaystoworkritodrine（利托君）terbutaline(特布他林)Beta-2adrenergicreceptoragonist,smoothmusclerelaxation,Magnesiumsulfatedelaylaborinthecaseofprematurelabor,todelaypreterm