Related Experiment Video
Updated: Aug 11, 2026

Bronchial Thermoplasty: A Novel Therapeutic Approach to Severe Asthma
Published on: November 5, 2010
[Day-night pattern of bronchial width and dyspnea: basis for selection of optimal dosage schedules for theophylline]
1School of Public Health, Department of Internal Medicine, University of Texas, Houston 77225.
Abstract:
Asthma typically worsens overnight. Although 24-hr variation in environment conditions may contribute to the worsening of dyspnea at night, this does not fully explain day-night patterns of this disease. Circadian (about 24-hr) rhythms in bioprocesses which influence airways patency constitute major contributory factors. The nighttime exacerbation of asthma may represent the influence of circadian bioperiodicities in bronchial patency, airways hyperreactivity to acetylcholine, histamine and house dust, and altered levels of several plasma constituents such as cortisol, adrenaline, histamine and cyclic AMP.
Related Concept Videos
Antiasthma Drugs: β2-Adrenoceptor Agonists
One class of bronchodilators includes β2-adrenoceptor agonists. These agents target the β2-adrenoceptors located on bronchial smooth muscle cells. By stimulating these receptors, β2-agonists induce relaxation in these...
Antiasthma Drugs: Methylxanthines
Theophylline is thought to inhibit phosphodiesterase enzymes, increasing intracellular levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). This rise in cAMP and cGMP concentrations stimulates cardiac function,...
COPD: Management Using Bronchodilators and Corticosteroids
Inhaled Medications
Chronopharmacokinetics: Circadian Rhythms and Influence on Drug Response
The time of drug administration is an important factor to consider, as it can influence the toxic dose of a drug. For example, a study conducted by Prins et al. in 1997 examined the effects of the timing of...
IV Infusion to Oral Dosing: Conversion Methods

