Oxytocin (Pitocin)

Pharmacologic Class:

Hormone; oxytocic

Oxytocin

(Pitocin)

Contraindications:

Antepartum use is contraindicated in the following: significant cephalopelvic disproportion; unfavorable fetal positions that are undeliverable without conversion before delivery; obstetrical emergencies in which the benefit-to-risk ratio for the fetus or mother favors surgical intervention; fetal distress when delivery is not imminent; when adequate uterine activity fails to achieve satisfactory progress; when the uterus is already hyperactive or hypertonic; when vaginal delivery is contraindicated, such as invasive cervical carcinoma, active genital herpes, total placenta previa, vasa previa, and umbilical cord presentation or prolapse of the cord.

Administration Alerts

Dilute 10 units of oxytocin in 1000 mL IV fluid prior to administration. For postpartum administration, may add up to 40 units in 1000 mL IV fluid. Incidence of allergic reactions is higher when given IM or by IV injection, rather than IV infusion. Pregnancy category X.

Therapeutic Class:

Drug to induce labor; uterine stimulant

Actions and Uses

Oxytocin (Pitocin), identical to the natural hormone secreted by the posterior pituitary gland, is a preferred drug for inducing labor. Oxytocin is given by different routes depending on its intended action. Given antepartum by IV infusion, oxytocin induces labor by increasing the frequency and force of uterine contractions. It is timed to the final stage of pregnancy, after the cervix has dilated, membranes have ruptured, and presentation of the fetus has occurred. Doses in an IV infusion are increased gradually, every 15-60 minutes, until a normal labor pattern is established. Oxytocin may also be administered postpartum to reduce hemorrhage after expulsion of the placenta and to aid in returning normal muscular tone to the uterus. This drug is approved at higher doses for the adjunct management of incomplete or inevitable abortion. Intranasal forms once used to promote milk letdown are no longer available in the United States.

Black Box Warning:

Oxytocin is not indicated for the elective induction of labor (the initiation of labor in a pregnant patient who has no medical indications for induction).

Adverse Effects

The most common adverse effects of oxytocin are rapid, painful uterine contractions and fetal tachycardia. When given IV, vital signs of the fetus and mother are monitored continuously to avoid complications in the fetus, such as dysrhythmias or intracranial hemorrhage. Serious complications in the mother may include uterine rupture, seizures, or coma. The risk of uterine rupture increases in women who have delivered five or more children.