Atosiban

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Atosiban is a medication used as a tocolytic to delay premature birth. It is a peptide and works by inhibiting the hormones oxytocin and vasopressin. Atosiban is administered via intravenous infusion and is typically used in the management of preterm labor.

Mechanism of Action

Atosiban functions as an oxytocin receptor antagonist. By blocking the action of oxytocin, it reduces uterine contractions, thereby delaying labor. This can be crucial in providing additional time for the administration of corticosteroids to enhance fetal lung maturity or for the transfer of the pregnant woman to a facility with a neonatal intensive care unit.

Indications

Atosiban is indicated for the treatment of preterm labor between 24 and 33 weeks of gestation. It is used when there are regular uterine contractions accompanied by cervical changes.

Administration

The medication is administered in three stages: 1. An initial bolus dose. 2. A continuous high-dose infusion for three hours. 3. A lower dose infusion for up to 45 hours.

The total duration of treatment should not exceed 48 hours.

Side Effects

Common side effects of atosiban include:

• Nausea
• Headache
• Dizziness
• Injection site reactions

Serious side effects are rare but may include:

• Allergic reactions
• Cardiac issues in the fetus

Contraindications

Atosiban should not be used in cases where:

• The fetus has a lethal congenital anomaly.
• There is intrauterine infection.
• The mother has severe preeclampsia or eclampsia.
• There is significant vaginal bleeding.

Pharmacokinetics

Atosiban has a rapid onset of action, with uterine contractions typically decreasing within 10 minutes of administration. It has a half-life of approximately 1.7 hours and is metabolized primarily in the liver.

History

Atosiban was developed in the late 20th century and has been approved for use in several countries. It is marketed under various brand names, including Tractocile.

See Also

• Preterm birth
• Tocolysis
• Oxytocin
• Vasopressin
• Corticosteroids