Theophylline is an organic compound with the chemical formula C7H8N4O2. It acts to reduce smooth muscle tone and dilate the airways; it promotes the release of endogenous epinephrine and norepinephrine, thereby inducing the relaxation of airway smooth muscles. Furthermore, it inhibits the release of calcium ions from the endoplasmic reticulum within smooth muscle cells, thereby lowering intracellular calcium concentrations and producing a bronchodilatory effect. While theophylline exerts a potent relaxant effect on smooth muscles, its efficacy in this regard is not as strong as that of beta-receptor agonists.
Theophylline presents as a white crystalline powder that is odorless and has a bitter taste. At room temperature, it is readily soluble in potassium hydroxide or ammonia solutions, though it is only slightly soluble in water. It is found primarily in tea, coffee, chocolate, cocoa, and related pharmaceutical preparations.
Due to its broad spectrum of pharmacological actions, theophylline is widely utilized in clinical therapeutics. In addition to possessing pharmacological properties similar to those of caffeine and theobromine-such as stimulating the central nervous system and acting as a diuretic-it also functions to dilate coronary arteries and relax bronchial smooth muscles. It is primarily indicated for the alleviation of wheezing symptoms associated with conditions such as bronchial asthma and obstructive pulmonary emphysema; it may also be employed to treat asthma-like symptoms resulting from cardiogenic pulmonary edema.
