Metabolic and respiratory effects of theophylline in the preterm infant.
BACKGROUND
Methylxanthines are often administered to preterm infants for the treatment of apnoea.


OBJECTIVE
To study the effects of theophylline on energy metabolism, physical activity, and lung mechanics in preterm infants.


METHODS
Indirect calorimetry was performed for six hours before and after administration of a bolus of theophylline (5 mg/kg) in 18 preterm infants while physical activity was recorded with a video camera. Lung mechanics measurements were performed at baseline and 12 and 24 hours after theophylline treatment.


RESULTS
Theophylline increased mean (SEM) energy expenditure by 15 (5) kJ/kg/day and augmented carbohydrate utilisation from 6.8 to 8.0 g/kg/day, but fat oxidation was unchanged. After theophylline treatment, preterm infants had faster respiration, lower transcutaneous CO2, and improved static respiratory compliance without increased physical activity.


CONCLUSIONS
A bolus of 5 mg/kg theophylline increased energy expenditure independently of physical activity, increased carbohydrate utilisation, and improved respiratory compliance. The increased energy expenditure could be detrimental to the growth of the preterm infant.
Carnielli
V P
VP
Dipartimento di Pediatria, Via Giustiniani 3, 35128 Padova, Italy. carnielli@child.pedi.unipd.it
Verlato
G
G
Benini
F
F
Rossi
K
K
Cavedagni
M
M
Filippone
M
M
Baraldi
E
E
Zacchello
F
F
D000628:Aminophylline / Q000494:pharmacology; D001993:Bronchodilator Agents / Q000494:pharmacology*; D002153:Calorimetry, Indirect; D004734:Energy Metabolism / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D005082:Physical Exertion / Q000187:drug effects; D011659:Pulmonary Gas Exchange / Q000187:drug effects; D015656:Respiratory Mechanics / Q000187:drug effects; D013806:Theophylline / Q000494:pharmacology*
D001993:Bronchodilator Agents; D010726:Phosphodiesterase Inhibitors; D000628:Aminophylline; D013806:Theophylline