Pitocin

Pi·to·cin (p-tsn)

A trademark for preparations of oxytocin.

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Pitocin,

trademark for an oxytocic (oxytocin).

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oxytocin

Pitocin

Pharmacologic class: Posterior pituitary hormone

Therapeutic class: Uterine-active agent

Pregnancy risk category NR

FDA Boxed Warning

• Drug isn't indicated for elective induction of labor (defined as initiation of labor in pregnant woman with no medical indications for induction). Available data aren't adequate to evaluate benefits versus risk.

Action

Unknown. Thought to directly stimulate smooth muscle contractions in uterus and cervix.

Availability

Injection: 10 units/ml ampule or vial

⊘Indications and dosages

➣ To induce or stimulate labor

Adults: Initially, 1-ml ampule (10 units) in compatible I.V. solution infused at 1 to 2 milliunits/minute (0.001 to 0.002 units/minute). Increase rate in increments of 1 to 2 milliunits/minute q 15 to 30 minutes until acceptable contraction pattern is established.

➣ To control postpartum bleeding

Adults: 10 to 40 units in compatible I.V. solution infused at rate adequate to control bleeding; or 10 units I.M. after placenta delivery

➣ Incomplete abortion

Adults: 10 units in compatible I.V. solution infused at 10 to 20 milliunits/minute (0.01 to 0.02 units/minute)

Off-label uses

• Antepartal fetal heart rate testing
• Breast enlargement

Contraindications

• Hypersensitivity to drug
• Cephalopelvic disproportion
• Fetal distress when delivery is not imminent
• Prolonged use in uterine inertia or severe toxemia
• Hypertonic or hyperactive uterine pattern
• Unfavorable fetal position or presentation that's undeliverable without conversion
• Labor induction or augmentation when vaginal delivery is contraindicated (as in invasive cervical cancer, active genital herpes, or total placenta previa)

Precautions

Use cautiously in:
• previous cervical or uterine surgery, history of uterine sepsis
• breastfeeding patients.

Administration

• Reconstitute by adding 1 ml (10 units) to 1,000 ml of normal saline solution, lactated Ringer's solution, or dextrose 5% in water.
☞ Don't give by I.V. bolus injection.
• Infuse I.V. using controlled-infusion device.
• Be aware that drug isn't routinely given I.M.
• Know that drug should be given only to inpatients at critical care facilities when prescriber is immediately available.

Route	Onset	Peak	Duration
I.V.	Immediate	40 min	1 hr
I.M.	3-5 min	40 min	2-3 hr

Adverse reactions

CNS: seizures, coma, neonatal brain damage, subarachnoid hemorrhage

CV: premature ventricular contractions, arrhythmias, neonatal bradycardia

GI: nausea, vomiting

GU: postpartal hemorrhage; pelvic hematoma; uterine hypertonicity, spasm, or tetanic contraction; abruptio placentae; uterine rupture (with excessive doses)

Hematologic: afibrinogenemia

Hepatic: neonatal jaundice

Other: hypersensitivity reactions including anaphylaxis, low 5-minute Apgar score (neonate)

Interactions

Drug-drug. Sympathomimetics: postpartal hypertension

Thiopental anesthetics: delayed anesthesia induction

Vasoconstrictors: severe hypertension (when given within 3 to 4 hours of oxytocin)

Drug-herbs. Ephedra (ma huang): increased hypertension

Patient monitoring

☞ Continuously monitor contractions, fetal and maternal heart rate, and maternal blood pressure and ECG. Discontinue infusion if uterine hyperactivity occurs.
☞ Monitor patient extremely closely during first and second stages of labor because of risk of cervical laceration, uterine rupture, and maternal and fetal death.
• When giving drug to control postpartal bleeding, monitor and record vaginal bleeding.
• Assess fluid intake and output. Watch for signs and symptoms of water intoxication.

Patient teaching

• Inform patient about risks and benefits of oxytocin-induced labor.
☞ Teach patient to recognize and immediately report adverse drug effects.

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Pitocin

Obstetrics A proprietary oxytocin, see there