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An evaluative study of the short-term effects of oncedaily, sustained-release theophylline on sleep in nocturnal asthmatics

Denise Richardt
Helen S. Driver


Objective. To examine the effects of once-daily, sustainedrelease theophylline on sleep patterns in nocturnal asthmatics.
Design. Double-blind, randomised, cross-over, placebocontrolled trial over 22 days. Seven-day period to establish therapeutic levels of theophylline (11.8 ± 3 mg/I); a-day cross-over period of 4 days' placebo or theophylline; 7-day baseline period. Electrophysiological sleep patterns, overnight bronchoconstriction and arterial O2 saturation monitored on nights 7, 11 and 15.
Setting. Sleep Laboratory, Medical School, University of the Witwatersrand.
Patients. Twelve volunteers who met the criteria for asthma, had previously used theophylline, were clinically stable and had a history of nocturnal awakenings caused by asthma were enrolled.
Outcome measures. Sleep-onset latency (SOL), withinsleep wakefulness WSw), rapid eye movement sleep (REM), slow-wave sleep (SWS), peak expiratory flow rate (PEFR) and arterial oxygen saturation.
Results. SOL increased on theophylline - 12 minutes (range 7 - 9 minutes) compared with placebo - 6 minutes (range 3 - 11 minutes); WSW increased from 33 minutes (range 17 - 66 minutes) on placebo to 72 minutes (range 35 - 150 minutes) on theophylline. REM sleep was unaltered. SWS decreased in 10 - 12 patients, but this difference was not significant. Early morning PEFR was significantly better on theophylline in all study limbs.
Conclusion. Our findings show that while once-daily, sustained-release theophylline improves bronchodilation in nocturnal asthmatics, it increases nocturnal wakefulness and decreases sleep efficiency during short-term treatment. This may, however, not be a long-term effect.