Nocturnal asthma: physiologic determinants and current therapeutic approaches.

Asthma has a tendency to destabilize at night in patients that are diurnaly active and try to sleep at night. As asthma worsens, the expression of this disease seems to increase at night. Additionally, nocturnal asthmatics have increased airway hyperresponsiveness and likely more active inflammation at night as compared with the daytime. Although the cause of nocturnal asthma cannot be completely explained, there do appear to be a variety of internal body circadian rhythms that play a role in this disease. Also, noncircadian rhythmic influences such as sleep, supine posture, snoring, and gastroesophageal reflux cannot be dismissed. Directing therapy, perhaps in unique ways, may be essential for the control of nocturnal asthma. Patients on inhaled corticosteroid therapy or nonsteroidal anti-inflammatory agents often persist in asthmatic disease expression at night. Long-acting bronchodilator therapy, either by inhalation or with sustained-release tablets, is often added to inhaled anti-inflammatory therapy for more complete 24-hour disease control. Using existing therapies but employing chronotherapeutic strategies is likely to improve the overall asthma management. By focusing on nocturnal asthma, we may be able to improve our understanding of this disease and more effectively control it over each 24-hour period.