[Beta 1-, beta 2-effects of ritrodine and terbutaline in the treatment of preterm labor (author's transl)].
beta 2-Stimulants are at present the most effective tocolytic agents. The aim of the study was to evaluate the beta 1- . beta 2-effects of terbutaline and ritodrine in the treatment of preterm labor. 1) Terbutaline, administered intravenously at a rate of 0.4-1.2 microgram/min, and ritodrine also at a rate of 50-300 microgram/min, effectively inhibited uterine activity during 180 minutes. Among the patients there was no difference in responses between those who received terbutaline and ritodrine. 2) The levels of c-AMP and c-GMP in the blood after administration of terbutaline or ritodrine increased and showed dose-response. The levels of c-AMP during a 180-minute infusion increased from 15 to 27 pmol/ml. 3) The action of c-AMP related substances on the circulatory systems was manifested as the dose-response of beta 1 action to the maternal blood pressure, maternal and fetal heart rate. Both beta 2-stimulants produced a tolerable changes in maternal heart rate and blood pressure, no significant changes during the infusion.
D000242:Cyclic AMP / Q000097:blood; D006152:Cyclic GMP / Q000097:blood; D004305:Dose-Response Relationship, Drug; D005260:Female; D005318:Fetal Heart / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007752:Obstetric Labor, Premature / Q000517:prevention & control*; D011247:Pregnancy; D011412:Propanolamines / Q000494:pharmacology*; D011941:Receptors, Adrenergic / Q000187:drug effects*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D012312:Ritodrine / Q000494:pharmacology*; D013726:Terbutaline / Q000494:pharmacology*; D014590:Uterine Contraction / Q000187:drug effects
D011412:Propanolamines; D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D000242:Cyclic AMP; D006152:Cyclic GMP; D012312:Ritodrine; D013726:Terbutaline