Terbutaline sulfate is a synthetic adrenergic bronchodilator. This drug is a β-adrenergic stimulant which has more selective effect on the β2-receptors of the bronchial, vascular, and uterine smooth muscles than on the β1-receptors of the heart.
Terbutaline sulfate is well absorbed following subcutaneous injection. It has an onset of action within 15 minutes, peak effects occur within 0.5-1 hour, and the duration of action ranges from 1.5-4 hours. The drug is partially metabolized in the liver, mainly to the inactive sulfate conjugate. Following injection, about 60% of a dose is excreted in the urine as unchanged drug, up to 3% is excreted in feces via the bile, and the remainder is excreted in urine as the conjugate. Terbutaline crosses the placenta and appears in breast milk.