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Syntocinon Side Effects

Generic name: oxytocin

Medically reviewed by Last updated on Dec 19, 2023.

Note: This document contains side effect information about oxytocin. Some dosage forms listed on this page may not apply to the brand name Syntocinon.

Applies to oxytocin: parenteral injection.

Side effects include:

Adverse effects usually are dose related.

Uterine hyperstimulation and subsequent fetal heart rate deceleration most common. (See Uterine Hyperactivity under General Precautions.)

Maternal nausea, vomiting, sinus bradycardia, premature ventricular complexes; probably related to labor and not the drug.

Neonatal hyperbilirubinemia, jaundice, retinal hemorrhage, low Apgar scores at 5 minutes.

For Healthcare Professionals

Applies to oxytocin: compounding powder, injectable solution, intravenous solution.


The more commonly reported adverse effects have included headache, tachycardia, bradycardia, nausea and vomiting.[Ref]


Common (1% to 10%): Tachycardia, bradycardia

Frequency not reported: Premature ventricular contractions, hypertensive episodes, cardiac arrhythmia, bradycardia (neonate), premature ventricular contractions and other arrhythmias (neonate)

Postmarketing reports: Myocardial ischemia, QTc prolongation, hypotension, flushing[Ref]

Bradycardia and premature ventricular contractions and other arrhythmias have been reported in the neonate due to induced uterine motility.[Ref]

Nervous system

Common (1% to 10%): Headache

Frequency not reported: Subarachnoid hemorrhage, permanent CNS or brain damage (neonate), neonatal seizures[Ref]

Permanent CNS or brain damage, and seizures have been reported in the neonate due to induced uterine motility.[Ref]


Frequency not reported: Severe water intoxication with convulsions, coma, fatal water intoxication

Postmarketing reports: Maternal hyponatremia, neonatal hyponatremia[Ref]


Frequency not reported: Anaphylactic reaction

Postmarketing reports: Anaphylactic reaction and shock[Ref]


Frequency not reported: Uterine Rupture, pelvic hematoma, postpartum hemorrhage

Postmarketing reports: Uterine hypertonicity, tetanic contractions, rupture of the uterus; fetal distress (neonate), amniotic fluid embolism[Ref]


Frequency not reported: Fatal afibrinogenemia

Postmarketing reports: Disseminated intravascular coagulation[Ref]


Frequency not reported: Neonatal jaundice[Ref]

Neonatal jaundice has been reported in the neonate due to use of oxytocin in the mother.[Ref]


Common (1% to 10%): Nausea, vomiting[Ref]


Postmarketing reports: Acute pulmonary edema, asphyxia (neonate)


Frequency not reported: Neonatal retinal hemorrhage[Ref]

Neonatal retinal hemorrhage has been reported in the neonate due to use of oxytocin in the mother.[Ref]


Frequency not reported: Fetal death, low Apgar scores at 5 minutes

Fetal death has been reported due to induced uterine motility; low Apgar scores at 5 minutes have been reported in the neonate due to oxytocin use in the mother.


Postmarketing reports: Angioedema


1. Product Information. Syntocinon (oxytocin). Sandoz Pharmaceuticals Corporation. 2001;PROD.

2. Cerner Multum, Inc. UK Summary of Product Characteristics.

3. Cerner Multum, Inc. Australian Product Information.

4. Product Information. Pitocin (oxytocin). Pfizer U.S. Pharmaceuticals Group. 2004.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.