A patient with asthma is taking an oral methylxanthine. Which of the following is an accurate characterization of this drug class?
|A||Eliminated almost exclusively by renal excretion, unchanged|
|B||Excellent anti-inflammatory actions|
|C||Frequently causes drowsiness, lethargy|
|D||Useful only for symptom prophylaxis|
a. A related drug, dyphylline, differs from the typical methylxanthines in one important way: theophylline derivative (not a theophylline salt) is eliminated by renal excretion, not by hepatic metabolism.
b. The implication is that dyphylline might be a “preferred” choice for patients who could benefit from a methylxanthine but have impaired liver function or are taking other drugs that interact by altering hepatic drug metabolism.
c. Nonetheless, as with the methylxanthines in general, given the other limitations of this drug class and the availability of other drug classes that are arguably more effective or safer for asthma control, there’s little good reason to use dyphylline either.