Atosiban
Aliases: Tractocile
Last verified: 2026-09-23
The short version
An oxytocin-receptor antagonist — stops preterm contractions (tocolysis).
Identity & type
- Molecular type
- analog
- Origin
- An oxytocin-receptor antagonist — stops preterm contractions (tocolysis).
Mechanism of action
Competitive OTR blockade in the uterus.
Dosing & routes
Official / clinical context
Approved drug — indications, dosing and warnings are defined by the official label. IV bolus + infusion up to 48 h.
Regulator-approved labeling and published study designs — never a recommendation.
Community-reported practice
IV bolus + infusion up to 48 h. An obstetric drug: stops preterm contractions; not used outside that context.
Unverified self-reports. Not medical advice. Not endorsement.
Expected effects (community)
An obstetric drug: stops preterm contractions; not used outside that context.
Protocol — official vs community
Official / label
Tractocile (preterm labor, 24–33 weeks): 6.75 mg IV bolus over 1 minute, then 18 mg/h IV for 3 hours, then 6 mg/h IV continued for up to 45 hours total; treatment stops if labor progresses.
Duration: One course per episode, capped at 45 hours; repeat courses are not label-supported.
An oxytocin-receptor antagonist whose selling point is tolerability — side effects are mild (nausea, headache, tachycardia) compared with beta-agonists. Its honest ceiling: it delays delivery to complete antenatal corticosteroids; it does not reduce preterm birth.
Community (anecdotal)
Structured protocol data for this entry is coming.
Human evidence
EU standard for tocolysis.
Preclinical evidence
The preclinical phase was completed and submitted to regulators as part of registration; pharmacology and toxicology details are part of the official label.
Known risks
- Mild: nausea, headache.characterized
Teal: characterized in clinical/labeling contexts. Amber: theoretical or reported outside controlled settings.
Unknowns & evidence gaps
- Real-world data outside controlled trials