Nocturnal wheeze is common in patients with
asthma, and slow release theophyllines may reduce symptoms. As theophyllines are stimulants of the central nervous system the effect of 10 days' twice daily treatment with sustained release
choline theophyllinate or placebo on symptoms, overnight bronchoconstriction, nocturnal oxygen saturation, and quality of sleep were studied in a double blind crossover study in nine stable patients with nocturnal
asthma (five men, four women, age range 23-64 years; forced expiratory volume in one second (FEV1) 0.85-3.8 1; vital capacity 1.95-6.1 1). When treated with the active
drug all patients had plasma
theophylline concentrations of at least 28 mmol/l (5 micrograms/ml) (peak plasma
theophylline concentrations 50-144 mmol/l (9-26 micrograms/ml]. Morning FEV1 was higher when treated with sustained release
choline theophyllinate (2.7 (SEM 0.3) 1) than placebo (2.1 (0.3) 1) (p less than 0.01). Both daytime and nocturnal symptoms were reduced when the patients were treated with sustained release
choline theophyllinate and subjective quality of sleep was improved (p less than 0.002). When treated with the active
drug, however, quality of sleep determined by electroencephalography deteriorated with an increase in wakefulness and drowsiness (p less than 0.05) and a reduction in non-rapid eye movement sleep (p less than 0.005). Treatment with
choline theophyllinate had no effect on either the occurrence or the severity of transient nocturnal hypoxaemic episodes or apnoeas or hypopnoeas. In conclusion, sustained release
choline theophyllinate prevents overnight bronchoconstriction, but impairs quality of sleep defined by electroencephalography.