oxytocin (Rx)

Frequency Not Defined

Sinus bradycardia, tachycardia, premature ventricular complexes & other arrhythmias

Permanent CNS or brain damage, and death secondary to asphyxia

Neonatal seizure

Neonatal jaundice

Fetal death

Low Apgar score (5 min)

Uteroplacental hypoperfusion & variable deceleration of fetal heart rate

Fetal hypoxia

Perinatal hepatic necrosis

Fetal hypercapnia

Severe decreases in maternal systolic & diastolic blood pressure, increases in heart rate, systemic venous return & cardiac output, & arrhythmia

Contraindications

Significant cephalopelvic disproportion

Unfavorable fetal positions or presentations, eg, transverse lies,which are undeliverable without conversion prior to delivery

Obstetric emergencies that favor surgery

Fetal distress where delivery is not imminent

Where adequate uterine activity fails to achieve satisfactory progress

Hyperactive or hypertonic uterus

Contraindicated vaginal delivery, eg, invasive cervical carcinoma, active herpes genitalis, total placenta previa, vasa previa, & cord presentation or prolapse of cord

Hypersensitivity

Fetal distress, polyhydramnios, partial placenta previa, prematurity, borderline cephalopelvic disproportion, previous major surgery of cervix or uterus (incl C-section), overdistension of uterus, grand multiparity, invasive cervical carcinoma, history of uterine sepsis or traumatic delivery

Hyperstimulation of the uterus, with strong (hypertonic) &/or prolonged (tetanic) contractions, or a resting uterine tone of 15-20 mm H2O between contractions may occur, possibly resulting in uterine rupture, cervical & vaginal lacerations, postpartum hemorrhage, abruptio placentae, impaired uterine blood flow, amniotic fluid embolism, & fetal trauma including intracranial hemorrhage

Not indicated for elective labor induction

Cautions

If uterine hyperactivity occurs, discontinue immediately

Intravenous preparations should be be administered by trained personnel

Risk of severe water intoxication on prolonged administration due to its antidiuretic effects

Restricting fluid intake may be warranted

Uterine hypertonicity, spasm, rupture of the uterus, and tetanic contractions may occur from high doses

IM not recommended for labor induction/augmentation

Pregnancy Category: X

Lactation: May be distributed milk; commencement of nursing should be delayed for at least 1 day when discontinued; use caution

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Uterine stimulant, vasopressive, & antidiuretic effects; activates G-protein-coupled receptors that trigger increases in intracellular calcium levels in uterine myofibrils, which results in uterine contractions; increases local prostaglandin production, which further stimulates uterine contraction

Pharmacokinetics

Duration: 2-3 hr (IM); 1 hr (IV)

Vd: 0.3 L/kg

Metabolism: Rapidly metabolized in the liver and plasma

Excretion: Urine (small amounts)

Half-Life: 1-6 min; decreased in late pregnancy and during lactation

IV Incompatibilities

Additive: fibrinolysin

IV Compatibilities

Solution: compatible w/ most common solvents

Additive: chloramphenicol sodium succinate, metaraminol, netilmicin, sodium bicarbonate, thiopental, verapamil

Y-site: heparin, hydrocortisone sodium succinate, insulin, meperidine, morphine sulfate, KCl, vitamin B/C, warfarin

IV Preparation

Dilute to 10 mU/mL by adding 10 U (1 mL) to 1000 mL of D5W, LR, or NS

IV/IM Administration

Administer by IV infusion using infusion control device, or

By IM injection (not recommended in most cases)

Storage

Store at room temperature (15-25°C)

Do not freeze

Do not use solution if discolored or contains precipitate