Name a commonly used xanthine derivative.

Theophylline is recognized as a commonly used xanthine derivative. Xanthine derivatives, such as theophylline, are bronchodilators that work by inhibiting the enzyme phosphodiesterase, leading to increased levels of cyclic AMP within the cells. This ultimately results in relaxation of the bronchial smooth muscle and dilation of the airways, which can be beneficial in the treatment of respiratory conditions like asthma and chronic obstructive pulmonary disease (COPD).

In addition, theophylline also exhibits anti-inflammatory properties, although its primary mechanism of action is as a bronchodilator. It requires careful dosing due to its narrow therapeutic window, and patients on theophylline are often monitored for serum drug levels to avoid toxicity.

Other options provided, such as albuterol, montelukast, and fluticasone, fall under different classes of medications. Albuterol is a short-acting beta-agonist, montelukast is a leukotriene receptor antagonist, and fluticasone is an inhaled corticosteroid. While all of these medications play important roles in respiratory therapy, they are not classified as xanthine derivatives.