oxytocin

(ox i toe' sin)
Parenteral: Pitocin, Syntocinon

Pregnancy Category C

Drug classes


Therapeutic actions


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.

Indications

Contraindications/cautions


Dosage


Available Forms: Injection--10 U/mL Adjust dosage based on uterine response.

Adult

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
IV drip:
Add 10---40 U to 1,000 mL of a nonhydrating diluent, run at a rate to control uterine atony.
IM:
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.

Pharmacokinetics

RouteOnsetDuration
IVImmediate60 min
IM3---5 min2---3 h

Metabolism: Hepatic, T1/2: 1---6 min

Distribution: Crosses placenta; enters breast milk

Excretion: Urine

IV facts


Adverse effects


Nursing Considerations


Assessment


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

Implementation



Drug-specific teaching points

Adverse effects in Italic are most common; those in Bold are life-threatening.