(ox i toe' sin)
Pregnancy Category C
Synthetic form of an endogenous hormone produced in the hypothalamus and stored in the posterior pituitary; stimulates the uterus, especially the gravid uterus just before parturition, and causes myoepithelium of the lacteal glands to contract, which results in milk ejection in lactating women.
- Antepartum: to initate or improve uterine contractions to achieve early vaginal delivery; stimulation or reinforcement of labor in selected cases of uterine inertia; management of inevitable or incomplete abortion; second trimester abortion (parenteral)
- Postpartum: to produce uterine contractions during the third stage of labor and to control postpartum bleeding or hemorrhage (parenteral)
- Unlabeled use: antepartum fetal heart rate testing (oxytocin challenge test), treatment of breast engorgement
- Significant cephalopelvic disproportion, unfavorable fetal positions or presentations, obstetric emergencies that favor surgical intervention, prolonged use in severe toxemia, uterine inertia, hypertonic uterine patterns, induction or augmentation of labor when vaginal delivery is contraindicated, previous cesarean section, pregnancy (nasal).
Available Forms: Injection--10 U/mL
Adjust dosage based on uterine response.
Induction or stimulation of labor:
Initial dose of no more than 1---2 mU/min (0.001---0.002 U/min) by IV infusion through an infusion pump. Increase the dose in increments of no more than 1---2 mU/min at 15- to 30-min intervals until a contraction pattern similar to normal labor is established. Do not exceed 20 mU/min. Discontinue in event of uterine hyperactivity, fetal distress.
Control of postpartum uterine bleeding
Add 10---40 U to 1,000 mL of a nonhydrating diluent, run at a rate to control uterine atony.
Administer 10 U after delivery of the placenta.
Treatment of incomplete or inevitable abortion:
IV infusion of 10 U of oxytocin with 500 mL physiologic saline solution or 5% dextrose in physiologic saline infused at a rate of 10---20 mU (20---40 drops)/min.
|IM||3---5 min||2---3 h|
Metabolism: Hepatic, T1/2: 1---6 min
Distribution: Crosses placenta; enters breast milk
- Preparation: Add 1 mL (10 U) to 1,000 mL of 0.9% Aqueous Sodium Chloride or other IV fluid; the resulting solution will contain 10 mU/mL (0.01 U/mL).
- Infusion: Infuse constant infusion pump to ensure accurate control of rate; rate determined by uterine response; begin with 1---2 mL/min and increase at 15---30-min intervals.
- Compatibilities: Compatible at a concentration of 5 U/L in Dextrose---Ringer's combinations; Dextrose---Lactated Ringer's combinations; Dextrose---Saline combinations; Dextrose 2%, 5%, and 10% in Water; Fructose 10% in Water; Ringer's Injection; Lactated Ringer's Injection; Sodium Chloride 0.45% and 0.9% Injection; and 1/6 M Sodium Lactate. Do not combine in solution with fibrinolysin or heparin.
- GI: Nausea, vomiting
- CV: Cardiac arrhythmias, PVCs, hypertension, subarachnoid hemorrhage
- GU: Postpartum hemorrhage, uterine rupture, pelvic hematoma, uterine hypertonicity, spasm, tetanic contraction, rupture of the uterus with excessive dosage or hypersensitivity
- Hypersensitivity: Anaphylactic reaction
- Fetal effects: Fetal bradycardia, neonatal jaundice, low Apgar scores
- Other: Maternal and fetal deaths when used to induce labor or in first or second stages of labor; fatal afibrinogenemia; severe water intoxication with convulsions and coma, maternal death (associated with slow oxytocin infusion over 24 h; oxytocin has antidiuretic effects)
History: Significant cephalopelvic disproportion, unfavorable fetal positions or presentations, severe toxemia, uterine inertia, hypertonic uterine patterns, previous cesarean section
Physical: Fetal heart rate (continuous monitoring is recommended); fetal positions; fetal-pelvic proportions; uterine tone; timing and rate of contractions; breast exam; orientation, reflexes; P, BP, edema; R, adventitious sounds; CBC, bleeding studies, urinary output
- Ensure fetal position and size and absence of complications that are contraindicated with oxytocin before therapy.
- Ensure continuous observation of patient receiving IV oxytocin for induction or stimulation of labor; fetal monitoring is preferred. A physician should be immediately available to deal with complications if they arise.
- Regulate rate of oxytocin delivery to establish uterine contractions that are similar to normal labor; monitor rate and strength of contractions; discontinue drug and notify physician at any sign of uterine hyperactivity or spasm.
- Monitor maternal BP during oxytocin administration, discontinue drug and notify physician with any sign of hypertensive emergency.
- Monitor neonate for the occurrence of jaundice.
Drug-specific teaching points
- The patient receiving parenteral oxytocin is usually receiving it as part of an immediate medical situation, and the drug teaching should be incorporated into the teaching about the procedure, labor, or complication of delivery that is involved. The patient needs to know the name of the drug and what she can expect once it is administered.
Adverse effects in Italic are most common; those in Bold are life-threatening.