<prompt> Oxytocin should be discontinued if the number of uterine contractions persists with frequency more than5 per 10 minutes5 per 15 minutes5 per 20 minutesAny of the above  <response>: Ans. a 5 per 10 minutes Ref. Williams Obstetrics 22ndCh. 22Oxytocin is a nanopeptide, synthesized in hypothalamus Paraventricular nucleus but stored and released by posterior pituitary. Its half life of 3-4 minutes. Alcohol inhibits its release. Uses: Stimulates labor, uterine contractions, milk let-down; controls uterine hemorrhage. Oxytocin when used for stimulation of labour should be discontinued if the number of contractions persists with a frequency 5 in a 10-min period or 7 in a 15-min period or with a persistent nonreassuring FHR pattern.INTRAVENOUS OXYTOCIN ADMINISTRATION for stimulation of labour The goal of induction or augmentation is to effect uterine activity sufficiently to produce cervical change and fetal descent while avoiding development of a nonreassuring fetal status. Discontinuation of oxytocin nearly always rapidly decreases the frequency of contractions. When oxytocin is stopped, its concentration in plasma rapidly falls because the mean half-life is approximately 5 min. It is found that a uterine response occurs within 3 to 5 minutes of beginning an oxytocin infusion and that a plasma steady state is reached in 40 minutes. Response depends on -- preexisting uterine activity,- cervical status,- pregnancy duration, and- individual biological differences. The uterine response to oxytocin increases from 20 to 30 weeks and increases rapidly at termEducational point: Maximal Dosage of oxytocin- The maximal effective dose of oxytocin to achieve adequate contractions in all cases is not known.- Wen and colleagues found that the likelihood of progression to a vaginal delivery decreases at and beyond an oxytocin dosage of 36 mUmin.- At a dosage of 72 mUmin, however, half of the nulliparas were delivered vaginally.- Thus, if contractions are not adequate--less than 200 Montevideo units--and if the fetal status is reassuring andlabor has arrested, an oxytocin infusion dose greater than 48 mUmin has no apparent risks.Hypothalamicpituitary drugs DRUGCLINICAL USE1.GHGH deficiency, Turner syndrome.2.Somatostatin octreotideAcromegaly, carcinoid, gastrinoma, glucagonoma, esophageal varices.3.OxytocinStimulates labor, uterine contractions, milk let-down; controls uterine hemorrhage.4.ADH DDAVPPituitary central, not nephrogenic Dl. 