Mechanism of action of theophylline in bronchial asthma is

Mechanism of action of methylxanthines like theophylline, caffeine: (a) Release of Calcium from the sarcoplasmic reticulum, especially in skeletal and cardiac muscle. (b) Inhibition of phosphodiesterase3 and PDE4 which degrades cyclic nucleotides intracellularly. (c) Blockade of adenosine receptors: adenosine acts as a local mediator in CNS, CVS and other organs-contracts smooth muscles, especially bronchial; dilates cerebral blood vessels, depresses cardiac pacemaker and inhibits gastric secretion. Beta 2 agonism is also correct because Theophylline acts synergistic with beta 2 agonistsPharmacology and pharmacotherapeutics Satoskar 24th page no. 579 ESSENTIALS OF MEDICAL PHARMACOLOGY 7TH EDITION KD TRIPATHI Page No:225,226