oxytocin

enUK

oxytocin

(ŏksĭtō`sĭn), hormonehormone,
secretory substance carried from one gland or organ of the body via the bloodstream to more or less specific tissues, where it exerts some influence upon the metabolism of the target tissue.
..... Click the link for more information. released from the posterior lobe of the pituitary glandpituitary gland,
small oval endocrine gland that lies at the base of the brain. It is sometimes called the master gland of the body because all the other endocrine glands depend on its secretions for stimulation (see endocrine system).
..... Click the link for more information. that facilitates uterine contractions and the milk-ejection reflex. The structure of oxytocin, a cyclic peptidepeptide,
organic compound composed of amino acids linked together chemically by peptide bonds. The peptide bond always involves a single covalent link between the α-carboxyl (oxygen-bearing carbon) of one amino acid and the amino nitrogen of a second amino acid.
..... Click the link for more information. consisting of nine amino acids, was determined in 1953 and in the same year it was synthesized in the laboratory. Both oxytocin and antidiuretic hormoneantidiuretic hormone
, polypeptide hormone secreted by the posterior pituitary gland. Its principal action is to regulate the amount of water excreted by the kidneys. Antidiuretic hormone (ADH), known also as vasopressin, causes the kidneys to resorb water directly from the
..... Click the link for more information. are biosynthesized in the hypothalamus of the brain and travel down neuronal axons to the posterior pituitary, where they accumulate prior to release. Stimuli that elicit the release of oxytocin include childbirth, suckling, and coitus; the uterine contractions that result may facilitate either childbirth or the ascent of spermatozoa through the fallopian tubes. Oxytocin may also play a role in the initiation of labor. The milk-ejection response occurs only in females immediately after childbirth. The role of oxytocin in males is unknown.

Oxytocin

(also pitocin), a hormone that is produced by the neurosecretory cells of the anterior nuclei of the hypothalamus. Oxytocin is transported over nerve fibers from the hypothalamus to the posterior lobe of the hypophysis, where it accumulates and is then released into the blood. It elicits contractions of the smooth muscles of the uterus and, to a lesser degree, the muscles of the urinary bladder and intestine. It also stimulates the flow of milk from the mammary glands. Oxytocin is secreted in response to stimulation of the nipple during lactation and distention of the uterus in the late stages of pregnancy. Adrenaline suppresses the secretion of oxytocin, and progesterone counteracts oxytocin’s effect on the uterine muscles.

Oxytocin is an octapeptide Whose four amino-acid groups are bound in a ring by cystine, which is also linked to a tripeptide:

Oxytocin—which is structurally similar to the other hypophyseal hormone, vasopressin—was isolated in pure form from biological substances (1950) and produced synthetically (1954) by V. du Vigneaud and co-workers; this was the first synthesis of a biologically active protein. A less expensive, synthetic oxytocin is used in medicine.

V. M. SAMSONOVA

oxytocin

[¦äk·sē¦tō·sən] (biochemistry) C₄₃H₆₆O₁₂N₁₂S₂ A polypeptide hormone secreted by the neurohypophysis that stimulates contraction of the uterine muscles.

oxytocin

enUK

oxytocin

[ok″se-to´sin] a hypothalamic hormone stored in and released from the posterior pituitary; it may also be prepared synthetically or obtained from the posterior pituitary of domestic animals. It acts as a powerful stimulant to the pregnant uterus, especially toward the end of gestation, and also causes milk to be expressed from the alveoli into the lactiferous ducts during breastfeeding. Injection of oxytocin may be used to induce labor or strengthen uterine contractions during labor, to contract uterine muscle after delivery of the placenta, and to control postpartum hemorrhage. It must be administered with care to avoid trauma to the mother or infant by hyperactivity of uterine muscles during labor. Oxytocin also may be administered intravenously by slow drip or applied to the mucous membranes of the nasal cavity to be absorbed into the bloodstream.oxytocin challenge test (OCT) a type of contraction stress test to assess placental reserve for transmitting oxygen to the fetus and detecting insufficiency by observing the fetal heart rate response to oxytocin-induced contraction. See also fetal monitoring.

oxytocin

Pitocin, Syntocinon (CA) (UK), Syntometrine (UK)

Pharmacologic class: Posterior pituitary hormone

Therapeutic class: Uterine-active agent

Pregnancy risk category NR

FDA Box Warning

• Drug isn't indicated for elective induction of labor (defined as initiation of labor in pregnant woman with no medical indications for induction). Available data aren't adequate to evaluate benefits versus risk.

Action

Unknown. Thought to directly stimulate smooth muscle contractions in uterus and cervix.

Availability

Injection: 10 units/ml ampule or vial

Indications and dosages

➣ To induce or stimulate labor

Adults: Initially, 1-ml ampule (10 units) in compatible I.V. solution infused at 1 to 2 milliunits/minute (0.001 to 0.002 units/minute). Increase rate in increments of 1 to 2 milliunits/minute q 15 to 30 minutes until acceptable contraction pattern is established.

➣ To control postpartum bleeding

Adults: 10 to 40 units in compatible I.V. solution infused at rate adequate to control bleeding; or 10 units I.M. after placenta delivery

➣ Incomplete abortion

Adults: 10 units in compatible I.V. solution infused at 10 to 20 milliunits/minute (0.01 to 0.02 units/minute)

Off-label uses

• Antepartal fetal heart rate testing

• Breast enlargement

Contraindications

• Hypersensitivity to drug

• Cephalopelvic disproportion

• Fetal distress when delivery is not imminent

• Prolonged use in uterine inertia or severe toxemia

• Hypertonic or hyperactive uterine pattern

• Unfavorable fetal position or presentation that's undeliverable without conversion

• Labor induction or augmentation when vaginal delivery is contraindi-cated (as in invasive cervical cancer, active genital herpes, or total placenta previa)

Precautions

Use cautiously in:

• previous cervical or uterine surgery, history of uterine sepsis

• breastfeeding patients.

Administration

• Reconstitute by adding 1 ml (10 units) to 1,000 ml of normal saline solution, lactated Ringer's solution, or dextrose 5% in water.

See Don't give by I.V. bolus injection.

• Infuse I.V. using controlled-infusion device.

• Be aware that drug isn't routinely given I.M.

• Know that drug should be given only to inpatients at critical care facilities when prescriber is immediately available.

Adverse reactions

CNS: seizures, coma, neonatal brain damage, subarachnoid hemorrhage

CV: premature ventricular contractions, arrhythmias, neonatal bradycardia

GI: nausea, vomiting

GU: postpartal hemorrhage; pelvic hematoma; uterine hypertonicity, spasm, or tetanic contraction; abruptio placentae; uterine rupture (with excessive doses)

Hematologic: afibrinogenemia

Hepatic: neonatal jaundice

Other: hypersensitivity reactions including anaphylaxis, low 5-minute Apgar score (neonate)

Interactions

Drug-drug. Sympathomimetics: postpartal hypertension

Thiopental anesthetics: delayed anesthesia induction

Vasoconstrictors: severe hypertension (when given within 3 to 4 hours of oxytocin)

Drug-herbs. Ephedra (ma huang): increased hypertension

Patient monitoring

See Continuously monitor contractions, fetal and maternal heart rate, and maternal blood pressure and ECG. Discontinue infusion if uterine hyper-activity occurs.

See Monitor patient extremely closely during first and second stages of labor because of risk of cervical laceration, uterine rupture, and maternal and fetal death.

• When giving drug to control postpartal bleeding, monitor and record vaginal bleeding.

• Assess fluid intake and output. Watch for signs and symptoms of water intoxication.

Patient teaching

• Inform patient about risks and benefits of oxytocin-induced labor.

See Teach patient to recognize and immediately report adverse drug effects.

p

ox·y·to·cin (OXT),

(ok'sē-tō'sin), A nonapeptide neurohypophysial hormone, differing from human vasopressin in having a leucyl residue at position 8 and an isoleucyl residue at position 3, that causes myometrial contractions at term and promotes milk release during lactation; used to induce or stimulate labor, to manage postpartum hemorrhage and atony, and to relieve painful breast engorgement. Synonym(s): ocytocin [G. okytokos, swift birth]

oxytocin

(ŏk′sĭ-tō′sĭn)n.1. A short polypeptide hormone, C₄₃H₆₆N₁₂O₁₂S₂, released from the posterior lobe of the pituitary gland, that stimulates the contraction of smooth muscle of the uterus during labor and facilitates ejection of milk from the breast during nursing.2. A synthetic form of this hormone, used as a drug to induce labor and to control postpartum hemorrhage.

oxytocin

Endocrinology A nonapeptide hormone which stimulates contraction of uterine smooth muscles and promotes milk ejection in females. Cf ADH.

ox·y·to·cin

(ok'si-tō'sin) A nonapeptide neurohypophysial hormone that causes myometrial contractions at term and promotes milk release during lactation; used for the induction or stimulation of labor, in the management of postpartum hemorrhage and atony, and to relieve painful breast engorgement. It is produced in the posterior pituitary gland.

oxytocin

An OXYTOCIC hormone produced by the pituitary gland. The hormone promotes contraction of the womb and the letdown of milk during suckling. It is used as a drug in obstetrics to bring on labour at term and to augment slow labour. There is recent evidence that the hormone may have a role to play in promoting trust between humans. The drug is on the WHO official list. A brand name is Syntocinon.

oxytocin

a hormone secreted by the posterior lobe of the PITUITARY GLAND,causing contraction of the uterine muscle. The hormone is important to parturition and, afterwards, for getting the uterus back to its normal size and shape.

Oxytocin

A hormone that stimulates the uterus to contract during child birth and the breasts to release milk.Mentioned in: Antepartum Testing, Pituitary Dwarfism, Stillbirth

ox·y·to·cin

(OXT) (ok'si-tō'sin) Nonapeptide neurohypophysial hormone that causes myometrial contractions at term and promotes milk release during lactation.

oxytocin

ox·y·to·cin

oxytocin

ox•y•to•cin

oxytocin

oxytocin

Oxytocin

oxytocin

oxytocin

oxytocin

oxytocin

FDA Box Warning

Action

Availability

Indications and dosages

Off-label uses

Contraindications

Precautions

Administration

Adverse reactions

Interactions

Patient monitoring

Patient teaching

p

ox·y·to·cin (OXT),

oxytocin

oxytocin

ox·y·to·cin

oxytocin

oxytocin

Oxytocin

ox·y·to·cin

oxytocin

Synonyms for oxytocin

noun hormone secreted by the posterior pituitary gland (trade name Pitocin)

Synonyms

Related Words