indication

For the treatment and prophylaxis of premature labour

pharmacology

Beta-2 adrenergic receptors are located at sympathetic neuroeffector junctions of many organs, including uterus. Ritodrine is beta-2 adrenergic agonist. It stimulates beta-2 adrenergic receptor, increases cAMP level and decreases intracellular calcium concentration. The decrease of calcium concentration leads to a relaxation of uterine smooth muscle and, therefore, a decrease in premature uterine contractions.

mechanism of action

Ritodrine is beta-2 adrenergic agonist. It binds to beta-2 adrenergic receptors on outer membrane of myometrial cell, activates adenyl cyclase to increase the level of cAMP which decreases intracellular calcium and leads to a decrease of uterine contractions.

toxicity

LD₅₀=64mg/kg (mice, IV); LD₅₀=540 mg/kg (mice, oral); LD₅₀=85 mg/kg (rat, IV)

biotransformation

Hepatic, by both the mother and fetus

half life

1.7-2.6 hours