[Hyponatremia and theophylline in very low birthweight premature infants]

A retrospective study of the occurrence of hyponatremia (i.e. less than 135 mmol/l) was carried out in 17 control preterm neonates and 25 infants treated with theophylline. These infants had a birthweight lower than 1,301 g and a gestational age less than 36 weeks. Despite a similar sodium and water intake in both groups, hyponatremia was detected at the age of 7-8 days in 37% infants treated with theophylline and none of the control infants. Their mean weight loss was 11% with theophylline and 5% in the controls. These data suggest that theophylline may play a role in the occurrence of hyponatremia of very low birthweight infants.