Atosiban

Summary

Atosiban is a synthetic nonapeptide analogue of oxytocin used as a tocolytic agent to delay preterm labor. It competitively inhibits oxytocin at uterine receptors, suppressing uterine contractions. Approved in the EU and several other countries for inhibition of imminent preterm birth between 24–33 weeks of gestation. Not approved in the United States.

Mechanism of Action

Competitive antagonist of oxytocin and vasopressin V1a receptors; inhibits oxytocin-induced uterine contractions by blocking myometrial oxytocin receptors, reducing intracellular calcium mobilization and decreasing uterine contractility

Routes of Administration

Goals & Uses

• Dysmenorrhea treatmentGynecologyLow
• Tocolysis (preterm labor inhibition)ObstetricsHigh
• Endometrial receptivity improvement (IVF)Reproductive MedicineLow
• Reduction of uterine contractionsObstetricsHigh

Contraindications

• Hypersensitivity to atosiban or excipientsAllergicHigh
• Intrauterine infection (chorioamnionitis)InfectiousHigh
• Gestational age < 24 weeks or > 33+6 weeksObstetricHigh
• Placenta praevia with hemorrhageObstetricHigh
• Severe preeclampsia or eclampsiaObstetricHigh
• Intrauterine fetal death or lethal fetal anomalyFetalHigh

Adverse Effects

• HyperglycemiaMetabolicUncommonAbnormally high blood glucose
• Injection site reactionsLocalCommon
• Tachycardia (maternal)CardiovascularUncommon
• HeadacheNeurologicCommonPain in the head or upper neck
• HypotensionCardiovascularUncommonLow blood pressure
• NauseaGastrointestinalCommonFeeling of sickness or urge to vomit

Drug Interactions

• OxytocinHigh
• Betamimetics (e.g., ritodrine, terbutaline)Moderate

Population Constraints

• Multiple gestationObstetricRelative
• Hepatic impairment (severe)HepaticRelative
• Renal impairmentOrgan ImpairmentRelative
• Gestational age < 24 weeksObstetricAbsolute

Regulatory Status

• European UnionApprovedApproved: Tocolysis to delay imminent preterm birth between 24 and 33 completed weeks of gestationApproved by EMA in 2000; marketed as Tractocile by Ferring Pharmaceuticals
• United StatesUnapprovedFDA rejected NDA in 2000 citing lack of neonatal benefit and safety concerns; not commercially available in the US
• United KingdomApprovedApproved: Tocolysis for preterm labor between 24 and 33 weeks gestationApproved and available post-Brexit under MHRA; consistent with prior EU approval

Approved in the EU (Tractocile) for tocolysis. The FDA declined approval in 2000 due to insufficient evidence of neonatal benefit and safety concerns. Available in over 60 countries outside the US.

Evidence & Sources

No sources recorded yet.