OXYTOCIN

Induction or enhancement of labour:

Oxytocin should not be started for 6 hours following administration of vaginal prostaglandins. Oxytocin should be administered as an iv drip infusion or, preferably, by means of a variable- speed infusion pump. For drip infusion it is recommended that 5 IU of oxytocin be added to 500ml of a physiological electrolyte solution.

4 “Special warnings and precautions for use”). To ensure even mixing, the bottle or bag must be turned upside down several times before use. The initial infusion rate should be set at 1 to 4mU/min (2 to 8 drops/min). It may be gradually increased at intervals not shorter than 20 min, until a contraction pattern similar to that of normal labour is established.

In pregnancy near term this can often be achieved with an infusion of less than 10mU/min (20 drops/min), and the recommended maximum rate is 20mU/min (40 drops/min). , 10 IU in 500ml. When using a motor-driven infusion pump which delivers smaller volumes than those given by drip infusion, the concentration suitable for infusion within the recommended dosage range must be calculated according to the specifications of the pump.

The frequency, strength, and duration of contractions as well as the foetal heart rate must be carefully monitored throughout the infusion. Once an adequate level of uterine activity is attained, aiming for 3 to 4 contractions every 10 minutes, the infusion rate can often be reduced.

In the event of uterine hyperactivity and/or foetal distress, the infusion must be discontinued immediately. 3 “Contra- indications”). Caesarean section: 5 IU by slow iv injection immediately after delivery.

Prevention of postpartum uterine haemorrhage:

The usual dose is 5 IU slowly iv after delivery of the placenta. In women given oxytocin for induction or enhancement of labour, the infusion should be continued at an increased rate during the third stage of labour and for the next few hours thereafter.

Treatment of postpartum uterine haemorrhage: 5 IU slowly iv, followed in severe cases by iv infusion of a solution containing 5 to 20 IU of oxytocin in 500ml of a non-hydrating diluent, run at the rate necessary to control uterine atony.

4 Special warnings and special precautions for use). 4 “Special warnings and precautions for use”). Symptoms of water intoxication include headache, nausea, vomiting and seizures. Rapid IV bolus injection of oxytocin may result in acute short-lasting hypotension accompanied with flushing and reflex tachycardia.

Exceptionally, skin rashes and anaphylactoid reactions or anaphylactic shock have been reported. Immune system disorders Exceptionally Anaphylactoid reaction or anaphylactic shock.

Nervous system disorders Very rarely Headache, seizures Cardiac disorders Common:

Tachycardia, bradycardia Rarely Arrhythmia Gastrointestinal disorders Rarely Nausea, vomiting Skin and subcutaneous tissue disorders Exceptionally Rash Reporting of suspected adverse reactions Reporting suspected adverse reactions after authorisation of the medicinal product is important.

It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the Yellow Card Scheme. uk/yellowcard.

Warnings Administration of oxytocin at excessive doses results in uterine overstimulation with hypertonicity of the uterus and may cause reversible foetal distress. QT interval prolongation has been observed after oxytocin administration.

Therefore it should be administered with caution in patients with potentially pro-arrhythmic conditions such as congenital or documented acquired QT prolongation. Precautions for use For the induction of labour, administration of oxytocin by direct IM or IV injection is formally avoided.

Administration by IV infusion should only be under qualified medical supervision. Careful monitoring of foetal heart rate and uterine motility is essential from the beginning to the end of delivery to prevent foetal distress or hypertonicity of the uterus reversible after oxytocin withdrawal.

In case of postpartum haemorrhage and postpartum atony, it remains essential to ensure of uterine vacuity before administration of oxytocin. It has been found that prostaglandins potentiate the effect of oxytocin. Therefore, if used in sequence, the patient's uterine activity should be carefully monitored.

In rare circumstances, the pharmacological induction of labour using uteronic agents increases the risk of postpartum disseminated intravascular coagulation (DIC). The pharmacological induction itself and not a particular agent is linked to such a risk.

This risk is increased in particular if the woman has additional risk factors for DIC such as being 35 years of age or over, complications during pregnancy and gestational age more than 40 weeks. In these women, oxytocin or any other alternative drug should be used with care, and the practitioner should be alerted by signs of DIC (fibrinolysis).

Because oxytocin possesses slight antidiuretic activity, its prolonged iv administration at high doses in conjunction with large volumes of fluid, as may be the case in the treatment of inevitable or missed abortion or in the management of postpartum haemorrhage, may cause water intoxication associated with hyponatraemia.

• Hypersensitivity to the active substance or to any of the excipients; • Dystocia; • Fragility or overdistension of the uterus; • Hypertonic uterine contractions or foetal distress, when delivery is not imminent; • Pre-eclamptic toxaemia and severe cardiovascular disorders; • Predisposition to amniotic fluid embolism (foetal death in utero, retroplacentar hematoma); • Placenta praevia.