Ritopar

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Ritodrine is indicated for the treatment of uncomplicated premature labour

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It is contraindicated in patients with known hypersensitivity to the active ingredient or any of the excipients of this component. β2-agonists are contra-indicated in cardiac disease and in patients with significant risk factors for myocardial ischaemia; they should also be avoided in antepartum haemorrhage, intra-uterine infection, intra-uterine fetal death, placenta praevia, abruptio placenta, threatened miscarriage, cord compression, and eclampsia or severe preeclampsia.

A selective β2-adrenoceptor agonist with its main action on the uterus, causing relaxation. It reduces the intensity and frequency of contractions. Heart rate is also increased while diastolic pressure is reduced. May cause bronchial relaxation but this is not clinically significant in its usage.

Increased risk of hypokalamia if high doses of corticosteroids, diuretics (acetazalamide, loop diuretics and thiazides) or theophylline given with high doses of ritodrine. A sufficient time interval should elapse prior to administration of another sympathomimetic drug. β–adrenergic blocking drugs inhibit its action; coadministraton of these drugs should, therefore, be avoided. With anesthetics used in surgery, the possibility that hypotensive effects may be potentiated should be considered.

The common side-effects of ritodrine hydrochloride are nausea, vomiting, flushing, sweating, tremor, hypokalaemia, tachycardia, palpitations, hypotension (left lateral position throughout infusion to minimize risk), uterine bleeding, pulmonary oedema; chest pain or tightness, arrhythmias and salivary gland enlargement. On prolonged administration for several weeks may cause leucopenia and agranulocytosis; liver function abnormalities including increased transaminases and hepatitis.

Symptoms of overdosage are tachycardia (maternal and fetal), palpitation, cardiac arrhythmia, hypotension, nervousness, tremor, nausea and vomiting. If an excess of ritodrine tablets is ingested, gastric lavage or induction of emesis should be carried out followed by administration of activated charcoal. When symptoms of overdose occur as a result of parenteral administration, ritodrine should be discontinued; an appropriate β-blocking agent may be usedas an antidote.

Ritodrine is a drug of pregnancy category B. There are no adequate and well controlled studies of effects in pregnant women before 20 weeks gestation; therefore, this drug should not be used before the 20th week of pregnancy. Studies in pregnant women from the 20th week of gestation onwards have not shown increased risk of fetal abnormalities. Nonetheless, although clinical studies did not indicate a risk of permanent adverse fetal effects from ritodrine, the possibility cannot be excluded; therefore, it should be used only when clearly indicated. In frequently reported neonatal symptoms include hypoglycemia and ileus. In addition, hypocalcemia and hypotension have been reported in neonates whose mothers were treated with other beta mimetic agents. Caution should be exercised unless the potential benefit of treatment to the mother outweighs any possible risk of the infants.

It should be used cautiously in patient with suspected cardiac diseases, hypertension, hyperthyroidism, hypokalaemia, diabetes mellitus, mild to moderate preeclampsia, monitor blood pressure and pulse rate and avoid over-hydration during taking ritodrine hydrochloride.