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 > 60 years), in congestive hea failure, pneumonia and liver failure.
Increases cAMP
Inhibits phosphodiesterase
Increase in dose is required in smokers
Increase in dose is required in cardiopulmonary disease