OXYTOCIN 5 USP UNITS IN DEXTROSE 5%
Clinical safety rating
cautionComprehensive clinical and safety monograph for OXYTOCIN 5 USP UNITS IN DEXTROSE 5% (OXYTOCIN 5 USP UNITS IN DEXTROSE 5%).
Comprehensive clinical and safety monograph for OXYTOCIN 5 USP UNITS IN DEXTROSE 5% (OXYTOCIN 5 USP UNITS IN DEXTROSE 5%).
Induction or augmentation of laborFacilitation of milk ejectionTreatment of postpartum hemorrhage (off-label)
Oxytocin is a nonapeptide hormone that binds to oxytocin receptors on the myometrium, increasing intracellular calcium and stimulating uterine smooth muscle contraction. It also acts on mammary gland myoepithelial cells to promote milk ejection.
| Metabolism | Rapidly metabolized in the liver and kidneys by oxytocinase (cystinyl aminopeptidase) and other peptidases. Small amounts are excreted unchanged in urine. |
| Excretion | Renal (primarily); >99% of infused oxytocin is excreted unchanged in urine; negligible biliary/fecal elimination. |
| Half-life | Terminal elimination half-life: 1–6 minutes (intravenous); 2–5 minutes (intramuscular); short half-life requires continuous infusion for sustained effect. |
| Protein binding | Low; approximately 30% bound to plasma proteins (no specific carrier protein identified). |
| Volume of Distribution | 0.2–0.3 L/kg; small Vd consistent with distribution primarily in extracellular fluid; does not readily cross placenta. |
| Bioavailability | Intravenous: 100%; Intramuscular: approximately 50% (due to first-pass hepatic metabolism after absorption). |
| Onset of Action | Intravenous: 30–60 seconds (uterine contraction); Intramuscular: 3–5 minutes; Subcutaneous: 3–5 minutes. |
| Duration of Action | Continuous infusion required for sustained uterine tone; single IV dose effect lasts 20–30 minutes; IM dose effect lasts 30–60 minutes. |
| Molecular Weight | 1007.19 |
Induction or augmentation of labor: IV infusion, initial rate 0.5-2 mU/min, increased by 1-2 mU/min every 15-30 min until adequate contractions; max 20 mU/min. Postpartum hemorrhage: IV infusion 10-40 units in 1000 mL D5W or NS, rate adjusted to control bleeding.
| Dosage form | INJECTABLE |
| Renal impairment | No dosage adjustment required for renal impairment. Oxytocin is extensively metabolized and renal excretion of unchanged drug is minimal. |
| Liver impairment | No dosage adjustment required for hepatic impairment. Oxytocin metabolism by liver is not significantly altered in liver disease. |
| Pediatric use | Not indicated for pediatric use. Oxytocin is only used in obstetrics for labor induction or postpartum hemorrhage in adults. |
| Geriatric use | Not indicated for geriatric use. Oxytocin is exclusively used in women of childbearing age for obstetrical indications. |
| 1st trimester | Use only for medically indicated induction/augmentation; not for routine use. Risk of uterine hyperstimulation and fetal distress. Category C. |
| 2nd trimester | Use only for medically indicated induction/augmentation; not for routine use. Risk of uterine hyperstimulation and fetal distress. |
| 3rd trimester | Use only for medically indicated induction/augmentation; not for routine use. Risk of uterine hyperstimulation and fetal distress. |
Clinical note
Comprehensive clinical and safety monograph for OXYTOCIN 5 USP UNITS IN DEXTROSE 5% (OXYTOCIN 5 USP UNITS IN DEXTROSE 5%).
| Placental transfer | Minimal transfer due to rapid metabolism by placental oxytocinase; endogenous oxytocin crosses placenta but exogenous doses used for induction are rapidly degraded. |
| Breastfeeding | Minimal excretion into breast milk; not orally bioavailable. Considered compatible with breastfeeding when used for postpartum indications. |
| Lactation Rating | L1 |
| Teratogenic Risk | FDA Pregnancy Category C. Oxytocin is not expected to increase the risk of major birth defects when used as indicated for labor induction/augmentation. However, high doses may cause uterine hyperstimulation leading to fetal distress, hypoxia, or neonatal morbidity. First trimester exposure is minimal as use is typically restricted to labor. No teratogenicity observed in animal studies but fetal risks are primarily related to uterotonic effects. |
| Fetal Monitoring | Continuous electronic fetal heart rate monitoring and uterine activity monitoring (tocodynamometry or intrauterine pressure catheter) are mandatory. Assess maternal vital signs (blood pressure, heart rate) and fluid balance due to risk of water intoxication with prolonged high-dose infusion. Monitor for signs of uterine hyperstimulation (tachysystole, hypertonus) or rupture. |
| Fertility Effects | No direct adverse effects on fertility. Oxytocin is used exogenously for labor induction and does not affect gametogenesis, implantation, or early pregnancy maintenance. Endogenous oxytocin plays a role in parturition and lactation but supplemental use does not impair reproductive potential. |
■ FDA Black Box Warning
WARNING: UTERINE RUPTURE AND FETAL INJURY. To be used only under close medical supervision. High doses or prolonged use may lead to uterine hyperstimulation, tetanic contractions, and uterine rupture. Fetal heart rate must be monitored continuously.
| Serious Effects |
Hypersensitivity to oxytocinSignificant cephalopelvic disproportionFetal distress where delivery is not imminentProlonged use in uterine inertiaActive genital herpes infectionNon-reassuring fetal status (e.g., bradycardia)Placenta previaVasa previaPrior classical cesarean section or major uterine surgeryGrand multiparity
| Precautions | Risk of uterine hyperstimulation, fetal distress, uterine rupture, water intoxication (especially when administered with large volumes of electrolyte-free solutions), severe hypotension, and anaphylaxis. Monitor uterine activity, fetal heart rate, and fluid balance. |
| Food/Dietary | None known. Patient should avoid excessive fluid intake to prevent water intoxication due to oxytocin's antidiuretic effect. |
| Clinical Pearls | Oxytocin should be administered as a controlled intravenous infusion via infusion pump to avoid uterine hyperstimulation. Initiate at 0.5-2 mU/min and titrate by 1-2 mU/min every 30-60 minutes as needed. Monitor fetal heart rate, uterine activity (tone, frequency, duration), and maternal vital signs continuously. Have magnesium sulfate available for tocolysis if hyperstimulation occurs. Oxytocin has antidiuretic effect; monitor fluid balance to avoid water intoxication. Nasal formulation not for induction/augmentation. |
| Patient Advice | Report any uterine contractions that are too frequent or painful, or changes in fetal movement. · You will be continuously monitored for your and your baby's heart rates and uterine activity. · Inform your healthcare provider if you experience headache, nausea, vomiting, or confusion (signs of fluid overload). · Do not adjust the infusion rate yourself; it will be controlled by the medical team. · This medication is used to start or strengthen labor contractions. |
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