Atosiban (Tractocile® or Antocin®, RWJ 22164) is an inhibitor of the hormones oxytocin and vasopressin, and is used intravenously in premature labor. Although initial studies suggested it could be used as a nose spray and hence would not require hospital admission, it is not used in that form. It was developed by Ferring Pharmaceuticals in Sweden and first reported in the literature by Akerlund et al in 1985.

Chemically, it is a modified form of oxytocin that inhibits the action of this hormone on the uterus, leading to a cessation of contractions. It is therefore a tocolytic.

Reference

• Akerlund M, Carlsson AM, Melin P, Trojnar J. The effect on the human uterus of two newly developed competitive inhibitors of oxytocin and vasopressin. Acta Obstet Gynecol Scand 1985;64(6):499-504. PMID 4061066.

Tocolytics