The concurrent use of
theophylline and beta2 agonist bronchodilators such as
salbutamol is a useful option in the management of asthma and chronic obstructive
pulmonary disease, but potentiation of some adverse reactions can occur. The most serious of these are hypokalaemia and tachycardia, particularly with high-dose
theophylline. Some patients may show a significant fall in
serum theophylline levels if given oral or
intravenous salbutamol or
intravenous isoprenaline (isoproterenol).
Potassium should be monitored, particularly in acutely unwell patients receiving high-dose
intravenous treatment. The CSM in the UK particularly recommends monitoring potassium levels in those with severe asthma as the hypokalaemic effects of beta2 agonists can be potentiated by
theophylline, corticosteroids, diuretics and
hypoxia.