UNDER REVIEW (September 2016)
Mechanism of Action:
Theophylline is a xanthine derivative drug that has a structural and pharmacological similarity to caffeine. It is naturally found in black tea and green tea. The mechanism of action is probably by inhibition of phosphodiesterase (PDE), an enzyme that breaks down the secondary messenger cyclicAMP. Potentiation of cAMP, the secondary messenger for beta-adrenoreceptors, leads to smooth muscle relaxation. Some of the effects of theophylline are therefore similar to beta-agonists. The main actions of theophylline are (1) relaxation of bronchial smooth muscle, (2) positive inotropic – increases heart muscle contractility and efficiency(3) positive chronotropic – increases heart rate, (4) lowers blood pressure, (5) increases renal blood flow, and (6) some anti-inflammatory effect. Theophylline may also antagonise the effects of adenosine.
Lecture and CAL materials: