The relaxing effect of terbutaline on the human uterus during term labor.

The uterine and cardiovascular responses to the adrenergic beta2-receptor stimulator terbutaline (TRB) were investigated in 14 patients in normal term labor. TRB, administered intravenously at a rate of 10 to 20 mug per minute, effectively inhibited uterine activity in advanced labor and also expulsion. Intravenous injection of TRB, 250 mug, diminished oxytocin-induced uterine hyperactivity. No serious side effects of the drug were observed; the circulatory effects were minimal, except for a tolerable maternal tachycardia. The mode of action and clinical application of TRB for inhibition of unwanted uterine activity are discussed.