oxytocin

Absorption: IV administration results in complete bioavailability.

Distribution: Widely distributed in extracellular fluid. Small amounts reach fetal circulation.

Metabolism/Excretion: Rapidly metabolized by liver and kidneys. Primarily excreted in urine as metabolites.

Half-Life: 3–9 min.

Time/Action Profile ⬆ ⬇

(reduction in uterine contractions)

ROUTE	ONSET	PEAK	DURATION
IV	immediate	unknown	1 hr
IM	3–5 min	unknown	30–60 min

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Anticipated nonvaginal delivery.

Use Cautiously in:

OB: 1st and 2nd stages of labor; slow infusion over 24 hr has caused water intoxication with seizure and coma or maternal death due to oxytocin's antidiuretic effect.

Adv. Reactions/Side Effects ⬆ ⬇

Maternal adverse reactions are noted for IV use only

CV:

maternal

hypotension,

fetal

arrhythmias

F and E:

maternal

hypochloremia, hyponatremia, water intoxication

GU:

maternal

↑uterine motility, painful contractions, abruptio placentae, ↓uterine blood flow

Neuro:

maternal

COMA, SEIZURES,

fetal

INTRACRANIAL HEMORRHAGE

Resp:

fetal

ASPHYXIA, hypoxia

Misc: hypersensitivity reactions

Interactions ⬆ ⬇

Drug-drug:

Severe hypertension may occur if oxytocin follows administration of vasopressors.

Route/Dosage ⬆ ⬇

Induction/Stimulation of Labor

IV (Adults ): 0.5–1 milliunits/min; ↑ by 1–2 milliunits/min every 30–60 min until desired contraction pattern established; dose may be ↓ after desired frequency of contractions is reached and labor has progressed to 5–6 cm dilation.

Postpartum Hemorrhage

IV (Adults ): 10 units infused at 20–40 milliunits/min.
IM (Adults ): 10 units after delivery of placenta.

Incomplete/Inevitable Abortion

IV (Adults ): 10 units at a rate of 20–40 milliunits/min.

Availability ⬆ ⬇

(Generic available)

Solution for injection: 10 units/mL

Assessment ⬆ ⬇

Fetal maturity, presentation, and pelvic adequacy should be assessed prior to administration of oxytocin for induction of labor.
Assess character, frequency, and duration of uterine contractions; resting uterine tone; and fetal heart rate frequently throughout administration. If contractions occur <2 min apart and are >50–65 mm Hg on monitor, if they last 60–90 sec or longer, or if a significant change in fetal heart rate develops, stop infusion and turn patient on her left side to prevent fetal anoxia. Notify health care professional immediately.
Monitor maternal BP and pulse frequently and fetal heart rate continuously throughout administration.
This drug occasionally causes water intoxication. Monitor patient for signs and symptoms (drowsiness, listlessness, confusion, headache, anuria) and notify physician or other health care professional if they occur.

Lab Test Considerations:

Monitor maternal electrolytes. Water retention may result in hypochloremia or hyponatremia.

Implementation ⬆ ⬇

Do not confuse oxytocin with Oxycontin.
Do not administer oxytocin simultaneously by more than one route.
IM: Ten units (1 mL) of oxytocin can be given after delivery of the placenta.

IV Administration:

Rotate infusion container to ensure thorough mixing. Store solution in refrigerator, but do not freeze.
- Infuse via infusion pump for accurate dose. Oxytocin should be connected via Y-site injection to an IV of 0.9% NaCl for use during adverse reactions.
- Magnesium sulfate should be available if needed for relaxation of myometrium.
- Dose of oxytocin is determined by uterine response.
Induction of Labor: Diluent: Dilute 1 mL (10 units) in 1 L of compatible infusion fluid (0.9% NaCl, D5W, or LR).Concentration: 10 milliunits/mL.
Rate: Begin infusion at 0.5–2 milliunits/min (0.05–0.2 mL); increase in increments of 1–2 milliunits/min at 15–30-min intervals until contractions simulate normal labor. Gradually increase dose at 30–60 min intervals in increments of 1–2 milliunits/min until the desired contraction pattern has been established. Once desired frequency of contractions has been reached and labor has progressed to 5–6 cm dilation, dose may be reduced by similar increments.
Postpartum Bleeding: Diluent: For control of postpartum bleeding, dilute 1–4 mL (10–40 units) in 1 L of compatible infusion fluid.Concentration: 10–40 milliunits/mL.
Rate: Begin infusion at a rate of 20–40 milliunits/min to control uterine atony. Adjust rate as indicated.
Incomplete or Inevitable Abortion: Diluent: For incomplete or inevitable abortion, dilute 1 mL (10 units) in 500 mL of 0.9% NaCl or D5W.Concentration: 20 milliunits/mL.
Rate: Infuse at a rate of 20–40 milliunits/min. Total dose should not exceed 30 units in a 12-hr period due to risk of water intoxication.

section name header

Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇

Time/Action Profile ⬆ ⬇

Contraind./Precautions ⬆ ⬇

Adv. Reactions/Side Effects ⬆ ⬇

Interactions ⬆ ⬇

Route/Dosage ⬆ ⬇

Availability ⬆ ⬇

Assessment ⬆ ⬇

Implementation ⬆ ⬇

Patient/Family Teaching ⬆ ⬇

Evaluation/Desired Outcomes ⬆ ⬇

US Brand Names ⬆