AlternativeTractocile
Atosiban
Oxytocin receptor antagonist
Alternative tocolytic when nifedipine contraindicated.
IV bolus + infusion
First-line for
- Tocolysis when CCBs contraindicated (cardiac, hypotension)
Mechanism
Competitive antagonism of myometrial oxytocin receptors → ↓ contraction frequency & intensity.
“Clean tocolytic”
- Minimal maternal SE
- No fetal effects
- Expensive — reserve for CCB CI
Dosing
- Bolus
- 6.75 mg IV over 1 min
- Infusion
- 18 mg/h × 3 h → 6 mg/h up to 45 h
Contraindications
- Absolute<24 or >33⁺⁶ weeks
- AbsoluteSevere pre-eclampsia, chorioamnionitis, abruption
Side effects
- Nausea, headache (mild)
- Injection site reaction
Fetal & maternal notes
- • No documented fetal adverse effects.
- • Does not affect labour after stopping.
Key interactions
Other tocolytics
CautionNo data — avoid combination
Clinical pearls
- 💡 Useful in multiple pregnancy or cardiac disease.
- 💡 Same neonatal outcomes as nifedipine but ~10× cost.
Content last reviewed: REPLACE_ME (e.g. 2026-07)
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