II. Indications

III. Mechanism

  1. Oxytocin is a hypothalamic polypetide stored in the posterior Pituitary Gland
    1. Oxytocin is encoded by the human OXT gene
  2. Oxytocin release is triggered by reflex response to Hypothalamus from infant sucking nipple
  3. Oxytocin acts to stimulate Smooth Muscle in the Uterus and in the Breast
    1. Increases force and frequency of uterine contractions
    2. Stimulates milk ejection in lactating women (contraction of alveolar myepithelium of the mammary glands)
  4. Oxytocin is similar in structure to the other posterior pituitary Hormone, Vasopressin (ADH)
    1. Oxytocin and Vasopressin differ by only 2 Amino Acid residues (out of 9 Amino Acids)
    2. Oxytocin may have Vasopressin-like effects (e.g. SIADH) with prolonged continuous infusion

IV. Medications

  1. Oxytocin 10 units/ml in 1 ml and 10 ml vials (multi-use)

V. Dosing: Labor Induction or Labor Augmentation

  1. See Labor Induction
  2. Precautions
    1. Use with a intravenous pump to maintain consistent and safe doses
    2. Continuous Fetal Monitoring
  3. Preparation: Oxytocin in Normal Saline Infusion
    1. Oxytocin 10 units in 1000 ml Normal Saline
      1. Starting rate of 6-12 ml/hour delivers 1-2 mU/minute
      2. Increasing rate 6 ml/hour delivers another 1 mU/min
    2. Oxytocin 20 units in 1000 ml Normal Saline
      1. Starting rate of 3-6 ml/hour delivers 1-2 mU/minute
      2. Increasing rate 3 ml/hour delivers another 1 mU/min
  4. Protocol: Low Dose (preferred)
    1. Start: 0.5 to 2 mU/minute
    2. Increase: 1-2 mU/minute every 15-40 minutes
      1. Base Pitocin rate changes on contractions
      2. After 8 mU/minute, may then increase by 2 mIU/minute
    3. Maximum: 40 mU/minute
  5. Protocol: High Dose
    1. See Monitoring below
    2. Precautions
      1. Low dose protocol is preferred in all patients (see Labor Induction for efficacy)
      2. As of 2019, evidence is against the use of high dose Oxytocin (see Labor Induction for efficacy)
      3. Use only in Nulliparous patients only
    3. Protocol
      1. Start: 6 mU/minute
      2. Increase: 3-6 mU/minute every 15-40 minutes
      3. Maximum: 40-42 mU/minute

VI. Dosing: Postpartum Hemorrhage Management and Prophylaxis

  1. Postpartum Hemorrhage prevention after Vaginal Delivery
    1. Oxytocin 10 units IM after delivery
    2. Oxytocin 10-40 units in 1 L IV fluid (NS, LR, D5W)
  2. Postpartum Hemorrhage prevention after Cesarean Section
    1. High dose Oxytocin prevents uterine atony
    2. Dose: Oxytocin 2667 mU/min for 30 minutes
    3. Munn (2001) Obstet Gynecol 98:386-90 +PMID: 11530117 [PubMed]

VII. Adverse Effects

  1. Anaphylaxis
  2. Uterine hypertonicity
    1. Uterine tetanic contractions and Fetal Distress
    2. Uterine Rupture
  3. Water Intoxication (SIADH)
    1. Associated with slow infusion >24 hours

VIII. Safety

  1. Avoid in Lactation
  2. In pregnancy, contraindicated, of course, prior to peripartum (at which point its primary use is pregnancy)
  3. Monitoring
    1. Continuous Fetal Monitoring

IX. Drug Interactions

  1. Sympathomimetics
    1. Increased risk of Postpartum Hemorrhage when combined with Oxytocin

X. Pharmacokinetics: Intravenous Oxytocin

  1. Onset: 3 to 5 minutes
  2. Duration: 30 minutes (up to 2 to 3 hours)
  3. Half-Life: 3 to 5 minutes

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Related Studies

Ontology: Oxytocin (C0030095)

Definition (MSH) A nonapeptide hormone released from the neurohypophysis (PITUITARY GLAND, POSTERIOR). It differs from VASOPRESSIN by two amino acids at residues 3 and 8. Oxytocin acts on SMOOTH MUSCLE CELLS, such as causing UTERINE CONTRACTIONS and MILK EJECTION.
Definition (NCI) Oxytocin (125 aa, ~13kDa) is encoded by the human OXT gene. This protein plays a role in smooth muscle contraction in both the mammary gland and uterus. Oxytocin also is involved in maternal-newborn bonding, cognition and many other psychological and physiological processes.
Definition (CSP) peptide hormone produced by the posterior lobe of the pituitary gland that induces contraction of the smooth muscle of the uterus and the myoepithelial cells of the mammary gland.
Concepts Pharmacologic Substance (T121) , Hormone (T125) , Amino Acid, Peptide, or Protein (T116)
MSH D010121
SnomedCT 12369008, 112115002
LNC LP15767-4, MTHU013002
English Ocytocin, Oxytocin, Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2, cyclic 1-6 disulfide, oxytocin, oxytocics oxytocin, oxytocin (medication), OXYTOCIN, Oxytocin [Chemical/Ingredient], ocytocin, Oxytocin preparation, Oxytocin product, Oxytocin (substance), Oxytocin preparation (product), Oxytocin preparation (substance), OXT
Swedish Oxytocin
Spanish preparado de oxitocina, preparado con oxitocina (producto), preparado con ocitocina, oxitocina (producto), preparado con oxitocina, ocitocina, oxitocina (sustancia), oxitocina, preparado de oxitocina (sustancia), preparado de ocitocina, preparado de oxitocina (producto), Oxitocina
Czech oxytocin
Finnish Oksitosiini
French Oxytocine, Ocytocine
Russian 3-IZOLEITSIN,8-LEITSIN-VAZOPRESSIN, OTSITOTSIN, VAZOPRESSIN, IZOLEITSIL-LEITSIL, OKSITOTSIN, IZOLEITSIL, LEITSIL-VAZOPRESSIN, AL'FA-GIPOFAMIN, VAZOTOTSIN, LEITSIL, 3-ИЗОЛЕЙЦИН,8-ЛЕЙЦИН-ВАЗОПРЕССИН, АЛЬФА-ГИПОФАМИН, ВАЗОПРЕССИН, ИЗОЛЕЙЦИЛ-ЛЕЙЦИЛ, ВАЗОТОЦИН, ЛЕЙЦИЛ, ИЗОЛЕЙЦИЛ, ЛЕЙЦИЛ-ВАЗОПРЕССИН, ОКСИТОЦИН, ОЦИТОЦИН
Japanese オシトシン, オキシトシン
Croatian OKSITOCIN
Polish Oksytocyna, Ocytocyna
Norwegian Oxytocin, Oksytocin
Portuguese Oxitocina, Ocitocina
German Ocytocin, Oxytocin
Italian Ossitocina

Ontology: Pitocin (C0733348)

Concepts Pharmacologic Substance (T121) , Hormone (T125) , Amino Acid, Peptide, or Protein (T116)
MSH D010121
French Pitocine
English pitocin, Pitocin
Norwegian Pitocin