Final answer:
The major side effect of Terbutaline is Tachycardia.
Step-by-step explanation:
The major side effect of beta-adrenergic tocolytic drugs (Terbutaline) is Tachycardia. Terbutaline is a beta-adrenergic agonist that acts on the beta-adrenergic receptors in the heart and lungs. By stimulating these receptors, Terbutaline relaxes the smooth muscles in the airways and uterus, which can help prevent premature labor. However, one of the side effects of Terbutaline is an increased heart rate or tachycardia.