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Library · Reproductive · Prevention of preterm labor in pregnancy

Atosiban

Tractocile, RW22164, RWJ-22164, ORF-22164

Synthetic oxytocin-receptor antagonist from 1985, used to delay preterm labor by blocking oxytocin’s effect on the uterus. Delays birth by at least 48 hours, allowing time for corticosteroids to mature fetal lungs; a standard tocolytic in Europe but not FDA-approved in the US.

Research score 90/100. Reference only, not a dose.

  • Hormone Regulation
  • Fertility Enhancement
  • Anti-inflammatory
  • Stress Relief
US status
Prescription Only
Approval
EMA Approved
Evidence
Oxytocin and vasopressin receptor antagonist used to delay preterm birth (24-33 weeks). Standard of care in many regions (EU).
Research score
90 / 100
Indication
Labor Induction
Origin
Sweden
Source category
Reproductive System
Status group
Approved / prescription

Mechanism

Competitively blocks oxytocin (and to a lesser extent vasopressin V1a) receptors on uterine muscle, cutting calcium-driven contractions via reduced phospholipase C/IP3 signaling, and lowering inflammatory cytokines linked to labor onset.

Safety file

Favorable safety profile; nausea (~14%), headache, and injection-site reactions are the main effects, with lower cardiovascular risk than beta-mimetics and no observed fetal toxicity.

  • Nausea
  • Vomiting
  • Headache
  • Chest pain
  • Injection site reactions