Ritodrine

Oral
Uncomplicated premature labour

Parenteral
Uncomplicated premature labour

Antepartum haemorrhage, eclampsia and severe preeclampsia, intrauterine foetal death, cardiac disease. Threatened miscarriage, placenta praevia and cord compression.

CV risk factors, concurrent steroids, hyperthyroidism, myocardial insufficiency, arrhythmias, hypertension, DM, bronchial asthma treated with beta-agonists, lactation. Monitor plasma glucose and potassium. Monitor maternal pulse throughout infusion; adjust rate to avoid maternal heart beat exceeding 140 beats/min. Monitor patient's hydration status to reduce risk of pulmonary oedema. Discontinue treatment if there are signs of pulmonary oedema.

Tachycardia, palpitation, headache, nervousness, anxiety, nausea, vomiting.
Potentially Fatal: Rarely, anaphylaxis, arrhythmia, pulmonary oedema, hypokalaemia.

IV/Parenteral/PO: B

May lead to tachycardia, CNS stimulation, hypokalaemia and hyperglycaemia.

May enhance neuromuscular blockade produced by pancuronium and vecuronium.
Potentially Fatal: Potassium-depleting drugs may increase risk of hypokalaemia.

Description:
Mechanism of Action: 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.
Pharmacokinetics:
Absorption: Rapid absorption from the GI tract (oral). Bioavailability: about 30% of an oral dose.
Distribution: Crosses the placenta.
Metabolism: Hepatic: By conjugation with glucuronic acid or sulfate.
Excretion: 70-90% of a dose is excreted in the urine within 10-12 hr.

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