Tocoban

Description

Tocoban 5 ml Infusion

Indications
Atosiban is indicated to delay imminent pre-term birth in pregnant adult women with:
regular uterine contractions of at least 30 seconds duration at a rate of ≥4 per 30 minutes
a cervical dilation of 1 to 3 cm (0-3 for nulliparas) and effacement of ≥50%
a gestational age from 24 until 33 completed weeks
a normal fetal heart rate

Pharmacology
It binds to membrane bound oxytocin receptors on the myometrium and prevents oxytocin-stimulated increases in inositol triphosphate production. This ultimately prevents release of stored calcium from the sarcoplasmic reticulum and subsequent opening of voltage gated calcium channels. This shutdown of cytosolic calcium increase prevents contractions of the uterine muscle, reducing the frequency of contractions and inducing uterine quiescence.

Atosiban has more recently been found to act as a biased ligand at oxytocin receptors. It acts as an antagonist of Gq coupling, explaining the inhibition of the inositol triphosphate pathway thought to be responsible for the effect on uterine contraction, but acts as an agonist of Gi coupling. This agonism produces a pro-inflammatory effect in the human amnion, activating pro-inflammatory signal tranducer NF-κB. It is thought that this reduces atosiban’s effectiveness compared to agents which do not produce inflammation as inflammatory mediators are known to play a role in the induction of labour.

Dosage & Administration
Atosiban is administered intravenously in three successive stages: an initial bolus dose (6.75 mg), performed with Atosiban 6.75 mg/0.9 ml solution for injection, immediately followed by a continuous high dose infusion (loading infusion 300 micrograms/min) of Atosiban 37.5 mg/5 ml concentrate for solution for infusion during three hours, followed by a lower dose of Atosiban 37.5 mg/5 ml concentrate for solution for infusion (subsequent infusion 100 micrograms/min) up to 45 hours. The duration of the treatment should not exceed 48 hours. The total dose given during a full course of Atosiban therapy should preferably not exceed 330.75 mg of atosiban.