Metabolic effects of salbutamol infusion during premature labour.

Plasma electrolytes, glucose and insulin concentrations were measured and serial electrocardiograms performed during the intravenous infusion of salbutamol to five women in premature labour. The plasma potassium (mean +/- standard error) fell from 3-5 +/- 0-1 to 2-7 +/- 0-1 mmol/l, and the glucose and insulin rose by 4-2 +/- 0-7 mmol/l (75 +/- 13 mg/100 ml) and 26 +/- 5 mU/l respectively. The maximum fall in potassium, and the rise in glucose and insulin occurred two hours after starting the infusion. No changes in other electrolytes were found. Electrocardiograms showed no signs of hypokalaemia. Highest pulse rates (148 +/- 4 beats per minute) occurred at two hours but no arrhythmias were observed.