All of the following statements regarding theophylline are true except:
Theophylline is a methylxanthine , used in the treatment of bronchial asthma. Its dose has to be reduced in elderly (age > 60years), in congestive hea failure, pneumonia and liver failure. Ref: Essentials of Medical Pharmacology, 5th Edition, Page 203
Increases cAMP
Inhibits phosphodiesterase
Increase in dose is required in smokers
Increase in dose is required in cardiopulmonary disease