Which of the following statements about theophylline is TRUE
Theophylline has a narrow therapeutic index. Its use has been declined due to narrow safety margin.
It inhibits the enzyme phosphodiesterase and thus decreases the metabolism of cAMP. It does not increase the forma­tion of cAMP.
Smoking is a powerful enzyme inducer. Dose of theophylline should be increased in smokers.
Children metabolize theophylline faster than adults whereas elderly metabolize it slowly. Therefore, the half-life of theophylline is shorter in children as compared to adults.
Its use in asthma has declined because of narrow safety margin
Its dose needs to be reduced in the smokers
It acts by increasing the formation of cAMP
Its plasma half life is longer in children as compared to that in adults