Clinical challenges of theophyllineTheophyllines (e.g. aminophylline, doxophylline, dihydroxypropyl theophylline, etc.) are mainly used in the clinical treatment of asthma, chronic obstructive pulmonary disease (COPD) and other respiratory diseases [3]. However, their clinical application faces many challenges, which are mainly reflected in the following aspects Narrow therapeutic window with large individual variability. Theophyllines have a narrow range of effective blood concentrations, typically 10-20 mg/L. Beyond this range, patients may experience serious adverse effects such as cardiac arrhythmias, seizures, and even death. In addition, there are significant individual differences in the metabolism of theophylline that are influenced by a variety of factors such as age, hepatic and renal function, and concomitant medications. For example, children and the elderly are more susceptible to toxic reactions due to incomplete or declining organ function. Adverse reactions are numerous. Adverse reactions to theophylline involve multiple systems, including the central nervous system (e.g., insomnia, irritability), cardiovascular system (e.g., tachycardia, arrhythmias), and gastrointestinal system (e.g., nausea, vomiting). The incidence of these adverse effects increases significantly with increasing blood levels. Therefore, the clinical use of theophylline must take into account a variety of factors, including individual differences, genetic testing, and drug monitoring to achieve accurate dosing.