Oxytocin (Systemic)


VA CLASSIFICATION
Primary: GU600
Secondary: DX900; HS900

Commonly used brand name(s): Pitocin; Syntocinon.

Note: For a listing of dosage forms and brand names by country availability, see Dosage Forms section(s).



Category:


Oxytocic—Oxytocin;

Antihemorrhagic (postpartum and postabortal uterine bleeding)—Oxytocin Injection;

Lactation stimulant—Oxytocin Nasal Solution;

Diagnostic aid (utero-placental insufficiency; placental reserve)—Oxytocin Injection;

Indications

Note: Bracketed information in the Indications section refers to uses that are not included in U.S. product labeling.

Accepted

Labor, medical induction of {02}{03}{09}{10}{12}{13}{15}{20}{21}{22}{25}{29}{30}{31}{32}{38}{40}{52} or
Labor, augmentation of or{02}{03}{09}{10}{12}{13}{20}{21}{22}{25}{26}{27}{28}{34}{35}{36}{48}{52}
Abortion, incomplete (treatment){02}{03}{10}{13}{14}{52}—Parenterally administered oxytocin is indicated for induction and augmentation of labor. Parenteral oxytocin is also indicated for management of incomplete abortion. {03} {13} {14} {52} Oxytocin is sometimes used in combination with prostaglandins {13} {20} {22} {52}.

Abortion, therapeutic{02}{03}{10}{13}{22}{45}{52}—Parenterally administered oxytocin is indicated for performance of therapeutic abortion {02} {03} {10} {13} {22} {45} {52}. Oxytocin is sometimes used in combination with hypertonic sodium chloride, urea, or prostaglandins {13} {20} {22} {52}.

Hemorrhage, postabortion and postpartum (treatment)—Oxytocin is indicated in the management of postabortion and postpartum bleeding or hemorrhage {02} {03} {09} {10} {12} {13} {23} {25} {52} {53} {54}.

Lactation deficiency (treatment)—Intranasally administered oxytocin is indicated for stimulation of impaired milk ejection (lack of let-down). {07} {08} {22} Nasal oxytocin is recommended for short-term use, generally during the first week postpartum {07} {22} {44}.

[Fetal distress (diagnosis)]1or
[Utero-placental insufficiency (diagnosis)]1—Oxytocin is administered parenterally to assess fetal-placental respiratory capabilities in high-risk pregnancies {14} {25} {37} {49} {55}. This is also referred to as the oxytocin challenge test {14} {25} {37} {49}.

1 Not included in Canadian product labeling.



Pharmacology/Pharmacokinetics

Physicochemical characteristics:
Source—
    Synthetically produced pituitary hormone {10} {13} {21} {25} {30} {47} {52}.
Molecular weight—
    1007.19 {01} {13} {52}

Mechanism of action/Effect:


Uterine:

The uterine myometrium contains receptors specific to oxytocin {10} {13} {25} {30} {46} {47} {51} {52}. Oxytocin stimulates contraction of uterine smooth muscle by increasing intracellular calcium concentrations, thus mimicking contractions of normal, spontaneous labor and transiently impeding uterine blood flow {02} {03} {10} {13} {52}. Amplitude and duration of uterine contractions are increased, leading to dilation and effacement of the cervix {02} {03} {10} {21} {25} {40} {50} {51}. The number of oxytocin receptors and, therefore, uterine response to oxytocin increases gradually throughout pregnancy, reaching its peak at term. {03} {10} {13} {21} {25} {30} {46} {47} {49} {51} {52}

For diagnosis of fetal distress and utero-placental insufficiency: By comparing baseline and oxytocin-induced fetal heart rate patterns and uterine contraction patterns, the oxytocin challenge test may aid in determining if there is adequate placental reserve for continuation of a high-risk pregnancy {14} {25}. The occurrence of a fetal heart rate pattern exhibiting late decelerations with administration of oxytocin may indicate utero-placental insufficiency {14} {19} {25} {56}.



Lactation:

Stimulates smooth muscle to facilitate ejection of milk from breasts {04} {07} {47}. Oxytocin does not increase milk production. {04} {07}


Absorption:

Rapidly absorbed through nasal mucous membranes {07}; may be erratic.

Protein binding:

Low (30%).

Biotransformation:

Enzymatic hydrolysis, primarily by tissue oxytocinase {16} {25} {30}. Oxytocinase is also found in placental tissue and plasma {16} {25} {30} {46}.

Half-life:

1 to 6 minutes (decreased in late pregnancy and lactation) {03} {13} {52}.

Onset of action:

Nasal—Within a few minutes.

Intramuscular—3 to 5 minutes {13} {52}.

Intravenous—Immediate {13} {52}.

Duration of action:

Nasal—20 minutes.

Intramuscular—2 to 3 hours {13} {52}.

Intravenous—Uterine activity generally subsides within one hour {13} {15} {52}.

Elimination:
    Only small amounts are excreted unchanged {03} {07} {10} {13} {52}.


Precautions to Consider

Carcinogenicity/Mutagenicity

No animal or human studies have been conducted to evaluate the carcinogenic or mutagenic potential of oxytocin. {02} {03} {10} {13} {52}

Pregnancy/Reproduction

Pregnancy—

For augmentation or stimulation of labor

Oxytocin is not indicated for use in the first trimester of pregnancy, other than for the treatment of incomplete abortion or therapeutic abortion {02} {10} {13} {52}.

Animal reproductive studies have not been conducted {02} {10} {13} {52}.



For stimulation of lactation

Not recommended for use during pregnancy because its use may result in contractions and abortion {07} {08}.

FDA Pregnancy Category X. {07} {08}



Labor and delivery—

Based on extensive clinical use and known pharmacologic properties of oxytocin, it is not expected to cause an increased risk of fetal abnormalities when used as indicated {02} {10} {13} {52}. Because of maternal and fetal risks, oxytocin must be administered with caution {03} {13} {17} {52}. It has been reported to cause fetal bradycardia, neonatal retinal hemorrhage, and neonatal jaundice, in addition to maternal effects {02} {03} {10} {13} {25} {26} {27} {32} {52}.

Fetal deaths due to various causes have reportedly been associated with the parenteral use of oxytocics for induction or augmentation of labor {02} {10} {13} {52}.

Excessive dosage or administration of oxytocin to hypersensitive patients may cause uterine hypertonicity with spasm and tetanic contraction or uterine rupture {02} {03} {10} {13} {25} {26} {30} {52}. Abruptio placentae, impaired uterine blood flow, amniotic fluid embolism, and fetal trauma including cardiac arrhythmias, intracranial hemorrhage, and asphyxia may occur as a result {02} {03} {10} {13} {25} {27} {30} {52}.

Oxytocin may inhibit, rather than promote, expulsion of the placenta and increase the risk of hemorrhage and infection {03}.

Breast-feeding

For stimulation of milk ejection—Problems in humans have not been documented. Only minimal amounts pass into breast milk. {07}

Drug interactions and/or related problems
The following drug interactions and/or related problems have been selected on the basis of their potential clinical significance (possible mechanism in parentheses where appropriate)—not necessarily inclusive (» = major clinical significance):


Note: Combinations containing any of the following medications, depending on the amount present, may also interact with this medication.

Anesthetics, hydrocarbon inhalation, such as{25}
Cyclopropane{02}{03}{10}{13}{25}{52}
Enflurane{25}
Halothane{25}
Isoflurane{25}    (cyclopropane anesthesia may lessen tachycardia but worsen hypotension caused by oxytocin {02} {03} {10} {13} {52}; maternal sinus bradycardia and abnormal atrioventricular rhythms have been reported with concurrent use {02} {10} {13} {52}, although the correlation is controversial {03})

    (enflurane [concentrations > 1.5%], halothane [concentrations > 1%], and possibly isoflurane produce a dose-dependent decrease in the uterine response to oxytocics and may abolish the response if sufficient concentrations [> 3% of enflurane] are administered; uterine hemorrhage may result {25})


Caudal block anesthesia with a vasoconstrictor or{02}{03}{09}{10}{13}{52}
Vasopressors{09}    (concurrent use with oxytocin may potentiate the pressor effect of the sympathomimetic pressor amines with possible severe hypertension and rupture of cerebral blood vessels {09})

    (severe hypertension has been reported when oxytocin was given 3 to 4 hours after caudal block anesthesia with a vasoconstrictor {02} {03} {09} {10} {13} {52})


» Sodium chloride, intra-amniotic for abortion or
» Urea, intra-amniotic for abortion or
» Oxytocics, other{09}{21}    (concurrent use with oxytocin may result in uterine hypertonus {09}, possibly causing uterine rupture or cervical laceration, especially in the absence of adequate cervical dilation; although combinations are sometimes used for therapeutic advantage, patient should be monitored closely during concurrent use; when used as an adjunct to abortifacients, it is recommended that oxytocin not be administered until the oxytocic effect of the abortifacient has subsided, to reduce the risk of uterine rupture and cervical laceration; water intoxication may also occur in patients given oxytocin following the use of intra-amniotic hypertonic saline for abortion)



Laboratory value alterations
The following have been selected on the basis of their potential clinical significance (possible effect in parentheses where appropriate)—not necessarily inclusive (» = major clinical significance):

With physiology/laboratory test values
Bilirubin, neonatal serum concentrations{25}{27}{41}{42}    (neonatal jaundice has been reported, although it is not clear whether jaundice is due to oxytocin or labor process itself {25} {41} {42})


Chloride and{44}
Sodium{44}{45}    (antidiuretic effect of oxytocin may cause reduced maternal serum concentrations and water intoxication {44} {45})


Medical considerations/Contraindications
The medical considerations/contraindications included have been selected on the basis of their potential clinical significance (reasons given in parentheses where appropriate)— not necessarily inclusive (» = major clinical significance).


Except under special circumstances, this medication should not be used when the following medical problems exist:

For all indications:
» Allergy to oxytocin, history of{02}{03}{09}{10}{13}{52}
For augmentation or induction of labor:
» Absolute contraindications to vaginal delivery{02}{22}
» Hypertonic uterine patterns{02}{03}{09}{10}{13}{52}
Risk-benefit should be considered when the following medical problems exist

For all indications, except for stimulation of lactation:
Cardiac disease, especially involving fixed cardiac output{09} or
Hypertension or
Renal function impairment    (increased susceptibility to fluid overload, arrhythmia, or hypotension and reflex tachycardia; reduction in dosage is recommended)


Exaggerated response to oxytocin or other oxytocics, history of{02}{03}{10}{13}{52}    (excessive dosage or administration of oxytocin to hypersensitive patients may cause uterine hypertonicity with spasm and tetanic contraction, which can lead to uterine rupture, cervical lacerations, abruptio placentae, impaired uterine blood flow, amniotic fluid embolism, and fetal trauma including cardiac arrhythmias, intracranial hemorrhage, and asphyxia {02} {03} {10})


For augmentation or induction of labor only, in addition to those problems listed above:
» Relative contraindications to vaginal delivery{22}
» Uterine inertia{02}{03}{09}{10}{40}{53}    (prolonged use of oxytocin is not recommended {02} {03} {09} {10} {40} {53}; in cases of uterine inertia, it is recommended that oxytocin be administered for no longer than 6 to 8 hours {53})



Patient monitoring
The following may be especially important in patient monitoring (other tests may be warranted in some patients, depending on condition; » = major clinical significance):

Acid-base equilibrium determinations, fetal and{26}{27}{30}{34}{35}{36}
Contractions—frequency, duration, and force of and{02}{03}{10}{13}{20}{21}{25}{26}{27}{30}{31}{34}{36}{38}{40}{49}{52}
Fetal heart rate monitoring, continuous and{02}{03}{10}{13}{16}{18}{20}{21}{25}{26}{27}{30}{31}{34}{36}{38}{40}{49}{52}
Heart rate and blood pressure determinations, maternal and{21}{25}{26}{30}{31}{49}
Uterine tone, resting{02}{03}{10}{20}{26}{30}{49}    (recommended at frequent intervals during labor and delivery {02} {10} {13} {20} {26} {30} {49} {52})


Fluid intake and output determinations{14}    (recommended to reduce the risk of water intoxication, especially during prolonged administration of oxytocin {14})




Side/Adverse Effects
The following side/adverse effects have been selected on the basis of their potential clinical significance (possible signs and symptoms in parentheses where appropriate)—not necessarily inclusive:

Those indicating need for medical attention
Incidence rare
With nasal use
    
Psychotic reaction —one case reported{07}
    
seizures —one case reported{07}{44}
    
unexpected uterine bleeding or contractions{07}

With parenteral use
    
Afibrinogenemia or{02}{03}{10}{11}{12}{13}{52} pelvic hematoma or{02}{03}{10}{13}{52} postpartum hemorrhage {02}{03}{10}{11}{12}{13}{25}{52}(increased or continuing vaginal bleeding)
    
allergy{03} or (skin rash or itching; hives), generalized anaphylaxis {02}{03}{10}{13}{43}{52}(difficulty in breathing; skin rash or itching; hives)
    
cardiac arrhythmias or{02}{03}{10}{13}{52} premature ventricular contractions{02}{03}{10}{13}{52} (fast or irregular heartbeat)
    
hypotension (weakness; dizziness), followed by hypertension{02} and (continuing or severe headache), reflexive tachycardia {25}(fast heartbeat)
    
uterine rupture {02}{10}{13}{24}{25}{52}(increased or continuing vaginal bleeding; severe pelvic or abdominal pain)
    
water intoxication {02}{03}{10}{13}{25}{44}{45}{52}(seizures; coma; confusion; continuing headache; rapid weight gain)

Note: Fatal allergic reactions have occurred with the use of oxytocin {03}.
Hypotension may be caused by administration of large doses or rapid intravenous infusion {25}.
Maternal death due to uterine rupture has been reported to be associated with the parenteral administration of oxytocics for the induction or augmentation of labor {10} {13} {52}.
Because of its slight antidiuretic effect, prolonged intravenous administration of oxytocin (usually in doses of 40 to 50 milliunits or more per minute) with large volumes of fluid may produce severe water intoxication {02} {03} {10} {13} {25} {45} {52}. Maternal deaths due to hypertensive episodes and subarachnoid hemorrhage have been reported {02} {03} {10} {13} {25} {52}.





Those indicating need for medical attention only if they continue or are bothersome
Incidence rare
With parenteral use
    
Nausea{02}{03}{10}{11}{12}{13}{52}
    
vomiting{02}{03}{10}{13}{52}

With nasal use
    
Lacrimation (tearing of the eyes){07}
    
nasal irritation{07}
    
rhinorrhea (runny nose){07}






Patient Consultation
As an aid to patient consultation, refer to Advice for the Patient, Oxytocin (Systemic).

In providing consultation, consider emphasizing the following selected information (» = major clinical significance):

Before using this medication
  Conditions affecting use, especially:
Allergy to oxytocin

Proper use of this medication

For intranasal use only
Proper administration

» Proper dosing

Precautions while using this medication
Possible therapeutic failure of nasal spray when used as lactation stimulant


Side/adverse effects
Signs of potential side effects, especially:

For parenteral use—Water intoxication, afibrinogenemia, pelvic hematoma, postpartum hemorrhage, anaphylaxis, allergy, cardiac arrhythmias, premature ventricular contractions, hypotension, and uterine rupture

For nasal use—Unexpected uterine bleeding or contractions, psychotic reaction, and seizures


General Dosing Information
Patients receiving oxytocin should be hospitalized and under the supervision of a physician experienced in its use {02} {03} {10} {13} {52}.

Therapeutic failure frequently occurs with the administration of nasal spray for stimulation of lactation. {03} {07}

For parenteral dosage forms only
Oxytocin must be diluted and administered by intravenous infusion for induction or stimulation of labor {02} {03} {10} {13} {21} {52}. Intramuscular administration of oxytocin is not recommended for induction or stimulation of labor, since intramuscular administration is difficult to regulate and may lead to uterine hyperactivity and fetal distress {13} {21} {30} {52}.

It is recommended that oxytocin infusion be administered intravenously by means of an infusion pump, a microdrip regulator, or a similar device to allow precise adjustment of the flow rate {02} {10} {13} {20} {21} {25} {30} {52}.

Dosage must be adjusted to meet the individual requirements of each patient, on the basis of maternal and fetal response {02} {10} {13} {21} {52}.

Oxytocin should not be used simultaneously by more than one route.

For treatment of adverse effects
Oxytocin infusion should be discontinued or the rate of infusion decreased at the first sign of uterine hyperactivity or fetal distress {02} {10} {13} {20} {21} {25} {27} {33} {35} {36} {38} {40} {48} {52} {53}. Supportive care, including administration of oxygen to the mother, is also recommended {02} {10} {13} {20} {21} {25} {33} {40} {52}.


Nasal Dosage Forms

OXYTOCIN NASAL SOLUTION USP

Usual adult dose
Lactation stimulant
Intranasal, 1 spray into one or both nostrils two to three minutes before nursing or pumping of breasts. {04} {05} {07} {08}


Strength(s) usually available
U.S.—


40 Units per mL (Rx) [Syntocinon{07}]

Canada—


40 Units per mL (Rx) [Syntocinon{08}]

Packaging and storage:
Store below 40 °C (104 °F), preferably between 15 and 30 °C (59 and 86 °F), unless otherwise specified by manufacturer.



Parenteral Dosage Forms

Note: Bracketed uses in the Dosage Forms section refer to categories of use and/or indications that are not included in U.S. product labeling.

OXYTOCIN INJECTION USP

Usual adult dose
Augmentation or
Induction of labor
Intravenous infusion, initially no more than 0.5 to 2 milliunits per minute, increased every fifteen to sixty minutes in increments of 1 to 2 milliunits per minute until adequate uterine activity is established, up to 20 milliunits per minute (usually 2 to 5 milliunits per minute) {02} {03} {09} {10} {13} {21} {25} {26} {28} {29} {30} {31} {32} {33} {38} {40} {48} {52} {53}. Occasionally, doses higher than 20 milliunits per minute may be required {22} {25} {29} {34} {35} {36} {53}.

The infusion rate may be reduced by similar increments, once labor is established {09} {13} {20} {52} {53}.

Abortion, incomplete (treatment) {02} {10} {13} {52} {53} or
Abortion, therapeutic {02} {10} {13} {52} {53}
Intravenous infusion, 10 Units at a rate of 20 to 40 milliunits per minute.

Hemorrhage, postpartum (treatment)
Intravenous infusion, 10 Units at a rate of 20 to 40 milliunits per minute following delivery of the infant(s) and preferably the placenta(s) {53}.

Intramuscular, 10 Units after delivery of the placenta(s) {02} {10} {13} {25} {52} {53}.

Hemorrhage, postabortion (treatment)
Intravenous infusion, 10 Units at a rate of 20 to 100 milliunits per minute {53}.

[Utero-placental insufficiency (diagnosis)]1
Intravenous infusion, initially 0.5 milliunits per minute, doubled every twenty minutes as necessary to the effective dose (usually 5 to 6 milliunits per minute) {53}. When three moderate uterine contractions (duration of forty to sixty seconds) occur in one ten-minute interval, the infusion is discontinued and baseline and oxytocin-induced fetal heart rate and uterine contraction patterns are compared {14} {19} {49} {53}.


Strength(s) usually available
U.S.—


10 Units per mL (Rx) [Pitocin{13}{52}] [Syntocinon][Generic]{02}{03}{06}{10}

Canada—


5 Units per mL (Rx) [Syntocinon{11}]


10 Units per mL (Rx) [Syntocinon{11}{12}]

Packaging and storage:
Store below 40 °C (104 °F), preferably between 15 and 30 °C (59 and 86 °F), unless otherwise specified by manufacturer {02} {10}. Protect from freezing {02} {10}.

Preparation of dosage form:
For augmentation or induction of labor—Using standard aseptic technique, add 10 units of Oxytocin Injection USP to 1000 mL of normal saline (0.9% sodium chloride injection), lactated Ringer's solution, or other nonhydrating diluent {02} {10} {13} {20} {21} {52}. Final solution concentration is 10 milliunits per mL {02} {03} {10} {13} {20} {52}.

For control of postabortion or postpartum uterine bleeding—Using standard aseptic technique, add 10 to 40 units of Oxytocin Injection USP to 1000 mL of a nonhydrating diluent {02} {10} {13} {52}. Final solution concentration is 10 to 40 milliunits per mL.



Revised: 06/30/1994



References

Note: All references used in the development and earlier revisions of this monograph have not yet been incorporated into the computer database and, therefore, are not listed below. Citations for information not yet referenced in the monograph will be provided upon request.

  1. USAN/DDN 1988.
  1. Oxytocin injection USP package insert (Lyphomed, U.S.), Rec 7/8/91, Rev 12/90.
  1. Wyeth Oxytocin Injection USP (synthetic) package insert, Rev. 2/10/88, Rec. 4/11/89.
  1. Syntocinon Nasal Spray, Rev 7/15/86. In: PDR 1988: 1885.
  1. ASHP. American Hospital Formulary Service. Bethesda: Author, 1988.
  1. Oxytocin injection USP, synthetic package insert (LyphoMed, US), Rec 3/89, Rev 7/87.
  1. Syntocinon package insert (Sandoz, US), Rec 10/31/88, Rev 7/15/88.
  1. Syntocinon product monograph (Sandoz). In: CPS 1988: 891.
  1. Oxytocin general monograph, Rev 1988. In: CPS 1988: 680.
  1. Oxytocin injection USP package insert (Wyeth, US), Rec 5/27/92, Rev 12/4/91.
  1. Syntocinon injection product monograph (Sandoz). In: CPS 1988: 890-1.
  1. Pitocin product monograph (Parke-Davis). In: CPS 1982: 450-1.
  1. Pitocin package insert (Parke-Davis), Rec 11/29/90, Rev 1/90.
  1. Panel comment, Panel survey 8/15/91.
  1. Manufacturer comment, Panel survey, 8/15/91.
  1. Panel comment, Panel survey, 8/15/91.
  1. Panel comment, Panel survey, 8/15/91.
  1. Panel comment, Panel survey, 8/15/91.
  1. Panel comment, Panel survey, 8/15/91.
  1. American College of Obstetricians and Gynecologists. Technical bulletin no. 110: induction and augmentation of labor. Washington, D.C.: Author, November 1987.
  1. American College of Obstetricians and Gynecologists. Technical bulletin no. 157: induction and augmentation of labor. Washington, D.C.: Author, July 1991.
  1. Panel consensus. USP DI Obstetrics and Gynecology panel meeting November 1991.
  1. American College of Obstetricians and Gynecologists. Technical bulletin no. 143: diagnosis and management of postpartum hemorrhage. Washington, D.C.: Author, July 1990.
  1. American College of Obstetricians and Gynecologists, Committee on obstetrics, maternal and fetal medicine. Committee opinion no. 64: Guidelines for vaginal delivery after a previous cesaerean birth. Washington, D.C.: Author, October 1988.
  1. Scott JR, et al., editors. Danforth's obstetrics and gynecology. 6th ed. Philadelphia: J.B. Lippincott Co, 1990.
  1. Foster T.C., Jacobson J.D., Valenzuela G.J. Oxytocin augmentation of labor: a comparison of 15- and 30-minute dose increment intervals. Obstet Gynecol 1988; 71(2): 147-9.
  1. Akuory HA, et al. Oxytocin augmentation of labor and perinatal outcome in nulliparas. Obstet Gynecol 1991; 78(2): 227-30.
  1. Cummiskey KC, Gall SA, Dawood MY. Pulsatile administration of oxytocin for augmentation of labor. Obstet Gynecol 1989; 74(6): 869-72.
  1. Mercer B, Pilgrim P, Sibai B. Labor induction with continuous low-dose oxytocin infusion: a randomized trial. Obstet Gynecol 1991; 77(5): 659-63.
  1. Blakemore KJ, Petrie RH. Oxytocin for the induction of labor [review]. Obstet Gynecol Clin N Am 1988; 15(2): 339-51.
  1. Satin AJ, Hankins GDV, Yeomans ER. A prospective study of two dosing regimens of oxytocin for the induction of labor in patients with unfavorable cervices. Am J Obstet Gynecol 1991; 165(4 Part 1): 980-4.
  1. Wein P. Efficacy of different starting doses of oxytocin for induction of labor. Obstet Gynecol 1989; 74(6): 863-8.
  1. Blakemore KJ, et al. A prospective comparison of hourly and quarter-hourly oxytocin dose increase intervals for the induction of labor at term. Obstet Gynecol 1990; 75(5): 757-61.
  1. Lopez-Zeno JA, et al. A controlled trial of a program for the active management of labor. New Engl J Med 1992; 326(7): 450-4.
  1. Cahill DJ, Boylan PC, O'Herlihy C. Does oxytocin augmentation increase perinatal risk in primigravid labor? Am J Obstet Gynecol 1992; 166(3): 847-50.
  1. Akoury HA, et al. Oxytocin augmentation of labor and perinatal outcome in nulliparas. Obstet Gynecol 1991; 78: 227-30.
  1. Lipitz S, et al. Breast stimulation test and oxytocin challenge test in fetal surveillance: prospective randomized study. Am J Obstet Gynecol 1987; 1178-81.
  1. Chua S, et al. Oxytocin titration for induction of labor: a prospective randomized study of 15 versus 30 minute dose increment schedules. Aust NZ Obstet Gynecol 1991; 31(2): 134-7.
    1. Mercer B, Pilgrim P, Sibai B. Labor induction with continuous low-dose oxytocin infusion: a randomized trial. Obstet Gynecol 1991; 77(5): 659-63.
    1. Buchan PC. Pathogenesis of neonatal hyperbilirubinaemia after induction of labour with oxytocin. BMJ 1979; 2: 1255-7.
    1. Calder AA, et al. Increased bilirubin levels in neonates after induction of labour by intravenous prostaglandin E 2 or oxytocin. Lancet 1974 Dec 7; 1339-42.
    1. Kawabarayashi T, et al. Anaphylactoid reaction to oxytocin during cesarean section. Gynecol Obstet Invest 1988; 25(4): 277-9.
    1. Seifer DB, Sandberg EC, Ueland K, et al. Water intoxication and hyponatremic encephalopathy from the use of oxytocin nasal spray. A case report. J Reprod Med 1985; 30(3): 225-8.
    1. Mwangingu FT. Water intoxication and oxytocin. BMJ 1985; 290: 113.
    1. Mizutani S, Tomado Y. Oxytocinase: placental cystine aminopeptidase or placental leucine aminopeptidase (P-LAP) [review]. Seminars in Reprod Endocrinol 1992; 10(2): 146-53.
    1. Jenkins JS, Nussey SS. The role of oxytocin: present concepts [review]. Clin Endocrinol 1991; 34: 515-25.
    1. Saunders NJ, et al. Oxytocin infusion during second stage of labour in primiparous women using epidural analgesia: a randomized double blind placebo controlled trial. BMJ 1989; 299: 1423-6.
    1. Takahashi K, et al. Uterine contractility and oxytocin sensitivity in preterm, term, and postterm pregnancy. Am J Obstet Gynecol 1980; 136(6): 774-9.
    1. Garfield RE, Hayashi RH. Appearance of gap junctions in the myometrium of women during labor. Am J Obstet Gynecol 1981; 140(3): 254-60.
    1. Fuchs A-R, Fuchs F, Husslein P, Soloff MS. Oxytocin receptors in the human uterus during pregnancy and parturition. Am J Obstet Gynecol 1984; 150(6): 734-41.
    1. Pitocin package insert (Parke-Davis) Rec 12/92, Rev 3/91.
    1. Panel consensus. Panel ballot date 9/17/92.
    1. Panel comment. Panel ballot date 9/17/92.
    1. Panel comment. Panel ballot date 9/17/92.
    1. Panel comment. Panel ballot date 9/17/92.
    Hide
    (web3)