Peptide Schedule
Atosiban (Tractocile)9 residues (approx.)CYITNCPRGEach bubble = one amino acid. Size = residue mass. Color = chemical class.Uses closest standard amino acids for non-standard residues.Atosiban (Tractocile) Dosage Calculator
Atosiban is a synthetic nonapeptide analogue of oxytocin that acts as a competitive antagonist at both oxytocin (OT) and vasopressin V1a receptors.
6.75mcg · Single dose
Summary: Add 0mL BAC water to your 0.9mg vial. Draw to < 0.1 units on a U-100 syringe for a 6.75mcg dose. This vial will last 0 doses.
Cycle Planner
Atosiban (Tractocile) Pharmacokinetics
Pharmacokinetics — Active Dose Over Time
t½ = Initial: ~13 min (tα), Terminal: ~1.7 hours (tβ)Disclaimer: This curve is a simplified first-order exponential decay model. Actual pharmacokinetics vary based on injection site, individual metabolism, body composition, and other factors. Half-life values are approximate and based on available preclinical and clinical literature. Many research peptides lack formal human pharmacokinetic studies. This is for educational purposes only — not medical advice.
Atosiban (Tractocile) Dosing Protocol
| Level | Dose / Injection | Frequency |
|---|---|---|
| Beginner | 6.75mg | Single dose |
| Moderate | 6.75mg | Single dose |
| Aggressive | 6.75mg | Single dose |
Note: Atosiban is administered IV only in a hospital setting: 6.75 mg bolus over 1 minute, then 300 mcg/min infusion for 3 hours, then 100 mcg/min for up to 45 hours. Maximum total dose per course is 330.75 mg. EU-approved (Tractocile) since January 2000; NOT FDA-approved. Treatment should not exceed 48 hours. Not for use before 24 weeks or after 33 weeks gestation.
About Atosiban (Tractocile)
Atosiban is a synthetic nonapeptide analogue of oxytocin that acts as a competitive antagonist at both oxytocin (OT) and vasopressin V1a receptors. Marketed in Europe under the brand name Tractocile, it was approved by the EMA in January 2000 and remains the only oxytocin receptor antagonist licensed for tocolysis — the pharmacological delay of preterm labor. Unlike beta-agonist tocolytics (e.g., ritodrine, terbutaline) which carry significant cardiovascular side effects, atosiban's receptor-selective mechanism gives it a substantially better maternal safety profile. In six pivotal clinical trials, atosiban significantly increased the proportion of women undelivered at 48 hours compared to placebo, providing a critical window for corticosteroid administration to accelerate fetal lung maturity. Atosiban's onset of action is rapid — uterine contractions are significantly reduced within 10 minutes of bolus injection, achieving stable uterine quiescence. The drug has minimal placental transfer (fetal-to-maternal ratio of 0.12), and plasma protein binding is 46-48%. It is metabolized to one major metabolite (M1) that retains roughly 10% of the parent compound's activity at the oxytocin receptor.