Neonatal Hypoglycemia After Administration of Tocolytic Drugs to Mothers

Tocolytic or β-sympathomimetic drugs (ritodrine, isoxsuprine, terbutaline, finoterol, salbutamol) are widely used to prevent premature delivery. The drugs are useful because of their rather selective β-2 effects which produce smooth muscle relaxation. These drugs have been considered relatively safe and the side effects are usually well tolerated; however, increasing reports of associated adverse reactions emphasize the necessity for extreme caution in their use. Serious adverse effects can occur both in mothers and neonates, especially when larger doses are used. Epstein et al found hypoglycemia in two thirds of babies whose mothers were treated with β-sympathomimetic drugs. These drugs stimulate cyclic adenosine monophosphate (cAMP), which induces glycogen release and breakdown from the muscles and liver causing an elevation in concentrations of blood glucose and insulin.