Overview
This lecture reviews Pitocin (oxytocin), its uses, mechanisms of action, side effects, nursing implications, and management of complications during labor induction and postpartum care.
Pitocin (Oxytocin) Overview
- Pitocin is a synthetic form of the hormone oxytocin, which stimulates uterine contractions and milk release.
- Naturally released from the posterior pituitary gland, but can be administered for medical purposes.
Indications and Administration
- Used to induce or augment labor and to treat postpartum hemorrhage.
- Can be administered intramuscularly (IM) after birth or intravenously (IV) during labor via infusion pump (IV piggyback).
- Dosing starts low (e.g., 1 milliunit/minute) and increases by 1-2 milliunits/minute every 30-60 minutes as per protocol.
- Always mixed in isotonic fluids (e.g., lactated Ringer's, normal saline) and follows facility guidelines.
Mechanism of Action
- Pitocin increases intracellular calcium in uterine smooth muscle cells, activating contractile proteins for contractions.
- Binds to oxytocin receptors, activating phospholipase C, which produces IP3, leading to calcium release from the sarcoplasmic reticulum.
- Additional calcium enters the cell via voltage-gated channels, strengthening contractions.
Pharmacokinetics and Effects
- IV Pitocin acts within minutes and has a short half-life (1–6 minutes).
- Rapidly decreases after stopping the infusion.
- High doses or prolonged use can cause water intoxication, hyponatremia, and hypertension due to antidiuretic and vasopressor effects similar to ADH (vasopressin).
Contraindications
- Do not use in patients with cervical cancer, placenta previa, macrosomia (>9.9 lbs / 4500g), gestational age <39 weeks, cord prolapse, active genital herpes, or abnormal fetal position.
Expected and Adverse Effects
- Expected: uterine contractions, nausea, vomiting.
- Goal: contractions every 2–3 minutes, lasting 40–70 seconds, moderate to strong intensity, with adequate rest between.
- Adverse effects ("PIT DRIP" mnemonic): hyperstimulation, sustained uterine tone (>20 mm Hg), tachysystole (>5 contractions/10 min), prolonged contractions (>120 sec), irregular fetal heart rate, and fluid retention.
Nursing Responsibilities
- Continuous monitoring of maternal vital signs, uterine contractions, and fetal heart rate.
- Monitor fluid input/output and lab values (especially sodium).
- Adjust or stop Pitocin if signs of hyperstimulation or fetal distress occur.
Management of Complications (The Five S's)
- Stop Pitocin infusion.
- Shift patient to lateral side (preferably left).
- Supply IV bolus fluid as per protocol.
- See how patient and baby respond.
- Supply oxygen if fetal heart rate remains abnormal; consider subcutaneous terbutaline if unresolved.
Key Terms & Definitions
- Oxytocin/Pitocin — hormone/medication that induces uterine contractions.
- Posterior pituitary gland — gland releasing natural oxytocin.
- Phospholipase C — enzyme activated by oxytocin receptor.
- IP3 (inositol trisphosphate) — molecule that releases calcium from storage.
- Tachysystole — excessive uterine contractions (>5 in 10 min).
- Antidiuretic hormone (ADH)/Vasopressin — hormone causing water retention.
Action Items / Next Steps
- Review hospital protocols for Pitocin administration.
- Access and complete the free quiz on this material.