Also available in 5 mg 25 mg 50 mg 100 mg 500 mg 1 mL 10 mM (in DMSO) and bulk. Please contact Fisher for quotes. Atosiban acetate (RW22164) is an inhibitor of the hormones oxytocin and vasopressin. It is used as an intravenous medication as a labour repressant (tocolytic) to halt premature labor. Atosiban acetate (RW22164) inhibits the oxytocin-mediated release of inositol trisphosphate from the myometrial cell membrane. There is reduced release of intracellular stored calcium from the sarcoplasmic reticulum of myometrial cells and reduced influx of Ca2+ from the extracellular space through voltage gated channels. Atosiban acetate (RW22164) suppresses oxytocin-mediated release of PGE and PGF from the decidua. In human pre-term labor atosiban at the recommended dosage antagonizes uterine contractions and induces uterine quiescence. The onset of uterus relaxation following atosiban is rapid reduced within 10 minutes. purity: 99%