Methylxanthines are a unique class of drug that are derived from the purine base xanthine. Xanthine is produced naturally by both plants and animals. The methylxanthines, theophylline, and dyphylline are used in the treatment of airways obstruction caused by conditions such as asthma, chronic bronchitis, or emphysema. Caffeine (present in coffee) and theobromine (present in chocolate) are also methylxanthines.
Theophylline is the most well known and most commonly used methylxanthine. At low dosages, it has an immunomodulatory, anti-inflammatory and bronchoprotective effect. Higher dosages are needed for its bronchodilator effect; however, higher dosages are often associated with toxicity.
Experts are not sure exactly how methylxanthines work but research has shown they inhibit the enzyme phosphodiesterase, antagonize adenosine receptors, and at lower dosages, their effects on histone deacetylase activity are believed to contribute to their immunomodulatory effects.
The main role of theophylline and dyphylline is to help maintain good airway control in chronic, persistent, airways disease.
