Ritodrine

What it is and how it works

Ritodrine stimulates beta2-adrenoceptors in uterine smooth muscle, increasing cyclic AMP and relaxing the myometrium, thereby inhibiting uterine contractions.

Indications

Short-term inhibition of uncomplicated premature labour (generally between 22 and 37 weeks of gestation) to allow time for corticosteroid administration or transfer to a specialist unit.

Dosage and administration (summary)

Given by controlled intravenous infusion, starting at a low rate and increased gradually according to uterine response and maternal heart rate, for a limited duration (in the EU, not more than 48 hours) under specialist supervision; oral use is no longer recommended in many countries.

Contraindications

Gestation under 22 weeks, conditions where prolonging pregnancy is hazardous (e.g. eclampsia or severe pre-eclampsia, intrauterine infection, antepartum haemorrhage, placenta praevia, intrauterine fetal death), maternal cardiac disease or significant risk factors for it, and uncontrolled hyperthyroidism or diabetes.

Warnings and precautions

Serious cardiovascular reactions, including pulmonary oedema, myocardial ischaemia and arrhythmias, may occur; monitor maternal pulse, blood pressure, fluid balance, ECG if indicated, blood glucose and potassium, and restrict fluid volume. Caution in multiple pregnancy and with corticosteroids or diabetes because of the risk of hyperglycaemia and fluid overload.

Pregnancy

Used only in pregnancy for premature labour under specialist supervision.

Storage and supply

Store below 25 °C, protected from light.

Source: reference summary prepared from the EU SmPC/EPAR, BNF and WHO Model Formulary. The approved product information in Iran governs.