Dosing and uses of Pitocin (oxytocin)
Adult dosage forms and strengths
injectable solution
- 10 units/mL
Postpartum Hemorrhage
10 unit IM after delivery of placenta
Add 10-40 units; not to exceed 40 units; to 1000 mL of nonhydrating IV solution and infuse at necessary rate to control uterine atony
Labor Induction
0.5-1 mUnit/min IV, titrate 1-2 mUnit/min q15-60min until contraction pattern reached that is similiar to normal labor (usually 6 mUnits/min); may decrease dose after desired frequency of contraction reached and labor has progressed to 5-6 cm dilation
Incomplete or Inevitable Abortion
10-20 mUnit/min; not to exceed 30 units/12 hr
Monitor
Intrauterine pressure, fetal heart rate
Prader-Willi Syndrome (Orphan)
Orphan designation for treatment of Prader-Willi syndrome
Sponsor
- Pr Maithe Tauber; Hospital des enfants, TSA70034 31059; Toulouse, FRANCE
Pediatric dosage forms and strengths
Not applicable
Pitocin (oxytocin) adverse (side) effects
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
Warnings
Black box warnings
Elective induction of labor is defined as the initiation of labor in a pregnant individual who has no medical indications for induction.
Because the available data are inadequate to evaluate the benefits-to-risks onsiderations, oxytocin is not indicated for elective induction of labor.
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 and lactation
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.
Pharmacology of Pitocin (oxytocin)
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
Administration
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
