Theophylline

Theophylline is a methylxanthine drug and is used in therapy for respiratory diseases, under a variety of brand names. It bears structural and pharmacological similarity to caffeine. It is naturally found in black tea and green tea.

The main actions of theophylline are:

• relaxation of bronchial smooth muscle
• positive inotropic (increases heart muscle contractility and efficiency)
• positive chronotropic (increases heart rate)
• lowers blood pressure
• increases renal blood flow
• some anti-inflammatory effect

The use of theophylline is complicated by the fact that it interacts with various drugs, chiefly cimetidine and phenytoin, and that it has a narrow therapeutic index, so its use must be monitored to avoid toxicity.

The main therapeutic uses of theophylline are:

• chronic obstructive diseases of the airways
  • chronic obstructive pulmonary disease COPD
  • bronchial asthma