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Endocrine · Reference monograph

Oxytocin-receptor antagonist used as a tocolytic

Reference compound — not available from Purity Peptides. Shown for research context.

Overview

Atosiban is a synthetic nonapeptide antagonist of the oxytocin receptor that also blocks the vasopressin V1a receptor. Structurally it is derived from oxytocin, with modifications at positions 1, 2, 4 and 8, including a deaminated, mercaptopropionic acid N-terminus and a D-amino acid at position 2, which convert the agonist scaffold into a competitive antagonist. It was developed by Ferring Pharmaceuticals.

Atosiban was approved in the EU in 2000, marketed as Tractocile, for delaying imminent preterm birth, and it is also approved in Brazil. The FDA did not approve it, and it is not available in the US. Atosiban was designed as a uterus-targeted alternative to older tocolytic agents such as beta-adrenergic agonists, which act on receptors throughout the body. Comparative trials against beta-agonists and calcium channel blockers have examined differences in maternal side-effect profiles, while placebo-controlled research continues to ask whether delaying delivery translates into improved neonatal outcomes. Atosiban has also been investigated in assisted reproduction research, where uterine contractility around embryo transfer is a variable of interest.

Mechanism studied

  1. Atosiban
  2. Oxytocin receptor blockade
  3. Contractions ↓
  4. Gestation endpoints

Atosiban competitively binds the oxytocin receptor on myometrial cells, preventing endogenous oxytocin from activating Gq-coupled phospholipase C signalling. This reduces inositol trisphosphate formation and calcium release from intracellular stores, lowering the frequency and strength of uterine contractions. It also blocks the vasopressin V1a receptor, which is expressed in the uterus and contributes to myometrial contractility. Because oxytocin receptor expression in the uterus rises toward term, the target is relatively tissue-specific, which is the rationale for its comparatively limited off-target effects in comparative studies. Some studies describe biased signalling at the oxytocin receptor, adding mechanistic nuance.

Research highlights

  • 01Developed by Ferring as an oxytocin-derived peptide antagonist with mixed oxytocin and V1a receptor activity.
  • 02Approved in the EU in 2000; not approved by the FDA.
  • 03Comparative trials against beta-agonists and nifedipine examined maternal tolerability differences.
  • 04Investigated in assisted reproduction research on uterine contractility around embryo transfer.
  • 05Open questions include whether delaying preterm delivery with tocolytics improves neonatal outcomes.

Latest published research

578 papers on PubMed →

  1. Role of the tail of the ventral tegmental area in the regulation of maternal behaviour: a pharmacological study in postpartum rats

    Pérez-Gozalbo C et al. · Neuropharmacology · 2026 Dec 1 · PMID 42604662

  2. Oxytocin Signalling in Lower Urinary Tract Symptoms Associated with Benign Prostatic Hyperplasia and Overactive Bladder Syndrome: A Narrative Review

    Badshah M et al. · Biomedicines · 2026 Oct 10 · PMID 42940112

  3. Characterization of cisternal, alveolar, and residual milk fractions in dromedary (Camelus dromedarius) and Bactrian camels (Camelus bactrianus)

    Nurseitova MA et al. · Tropical animal health and production · 2026 Oct 10 · PMID 42859315

  4. Pharmacological characterization of neuromodulatory systems involved in biased social interaction toward stressed conspecifics in male rats

    Kiyokawa Y et al. · Social neuroscience · 2026 Oct 1 · PMID 42820313

  5. Drug repurposing identifies candidate uterus-selective tocolytics for preterm labor

    Siricilla S et al. · Science translational medicine · 2026 Sep 23 · PMID 42777085

  6. Discovery of an antagonist nanobody targeting the oxytocin receptor with tocolytic effect in mice

    Nie J et al. · Nature communications · 2026 Sep 11 · PMID 42864336

  7. Atosiban versus nifedipine for the management of preterm labor: a systematic review and meta-analysis of randomized controlled trials

    Pascon A et al. · Revista brasileira de ginecologia e obstetricia : revista da Federacao Brasileira das Sociedades de Ginecologia e Obstetricia · 2026 · PMID 42923929

  8. Delicate Balance of Intra- and Inter-Molecular Entropic Effects in S-S Peptide Cyclization

    Medvedev MG et al. · The journal of physical chemistry. A · 2026 Aug 13 · PMID 42593195

Live feed from PubMed (NCBI) for “Atosiban”, updated 2026-10-30. Listing a paper is not an endorsement of its findings.

Registered studies

23 on ClinicalTrials.gov →

From the public ClinicalTrials.gov registry for “Atosiban”, updated 2026-10-30. Shown for research context only; Purity Peptides products are not for human use.

Key references

  1. [1]Manufacturer's prescribing information — FDA / EMA / ANVISA
  2. [2]PubMed — reviews on atosiban and preterm labour

FAQ

  • Beta-adrenergic agonists act on receptors throughout the body, affecting the heart and metabolism. Atosiban targets oxytocin and V1a receptors that are concentrated in the uterus near term, which was intended to give a more tissue-focused profile.

  • The FDA did not approve atosiban when it was reviewed in the late 1990s. It is authorised in the EU and several other regions, and it remains a subject of international comparative research.

  • Atosiban is a competitive antagonist at the oxytocin receptor and also blocks the vasopressin V1a receptor. Both receptors contribute to myometrial contractility, making atosiban a useful tool in uterine signalling research.

FOR RESEARCH USE ONLY.Not for human or veterinary use. Not intended to diagnose, treat, cure, or prevent any disease.

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