The effects of midodrine and alpha-2,5-dimethoxyphenyl-beta-aminoethanol hydrochloride on the rat uterus in situ.

In urethane anaesthetized rats 1 mg/kg i.v. alpha-2,5-dimethoxyphenyl-beta-glycinamidoethanol hydrochloride (midodrine, Gutron) or 0.1 mg/kg of its main metabolite alpha-2,5-dimethoxyphenyl-beta-aminoethanol hydrochloride (ST 1059) do not increase the uterine motility while these doses elevate the arterial blood pressure, 5 mg/kg midodrine or 0.3 mg/kg ST 1059 increase the uterine motility with concomitant increases in blood pressure and decreases in heart rate. It is concluded that midodrine does not enhance the uterine activity in doses clinically used for the treatment of hypotensive circulatory disorders.