You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Half-life of IV oxytocin? and explain in detail?
Ans. b (3 minutes) (Ref. KDT 6th/320; Williams Obstetrics 22nd/Ch. 22; p. 540)KDT 6th/320 and Internet:Oxytocin, produced by the hypothalamus and stored and secreted by the posterior pituitary gland, is a peptide of nine amino acids (a nonapeptide). It is rapidly degraded in liver and kidney; plasma half life = 6 minutes and is shortened at term.OXYTOCIN# Oxytocin causes milk ejection, contraction of pregnant uterus.6# Oxytocin--mainly used for induction of labour.# It is found that a uterine response to oxytoxin for inducting labour 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 term.# Oxytocin should be discontinued if: Q- the number of contractions persists with a frequency greater than five in a 10-minute period or- seven in a 15-minute period or- with a persistent nonreassuring fetal heart rate pattern.# The mean half-life of oxytocin is = 5 minutes Q (hence when it is stopped, its concentration in plasma rapidly falls).# Maximal Dosage of oxytocin:- It is found that the likelihood of progression to a vaginal delivery decreases at and beyond an oxytocin dosage of 36 mU/min.- However, if contractions are not adequate--less than 200 Montevideo units--and if the fetal status is reassuring and labor has arrested, an oxytocin infusion dose greater than 48 mU/min has no apparent risks.# Contraindications and S/Es of oxytocin:ContraindicationsSide effectsa) Grand multiparaUterine ruptureb) Contracted pelvisHypotensionc) MalpresentationAntidiuresisd) Obstructed labourPituitary shocke) Incoordinate uterine contractionsAnginal painf) Hypovolemia and cardiac diseases Oxytocin Challenge test (Syn: contraction stress test)# Indications (are very selective)- IUGR,- Post-maturity,- Pregnancy with DM,- Hypertension.# Contraindications- Compromised foetus,- Previous ISCS- APH,- Threat of preterm labour# It takes at least 1-2 hr to perform the test.Educational PointATOSIBAN# Atosiban is an oxytocin receptor antagonist with high uterine specificity.