Sustained-release methylxanthine drugs are used to neutralize symptoms asthma, by diminishing the swelling of the bronchial tubes and facilitate breathing. are used to control inflammation. It is used in mild to moderate cases of regularly occurring asthma. An inhaled corticosteroid is often used in conjunction with it, to keep symptoms under check when sleeping.

Methylxanthine drugs can be used in place of other types of asthma medication when the patient is either incapable of or unwilling to use an inhaler. It can also be used as a supplementary medication for people who do not use inhaled corticosteroids to keep their asthma in control.

However, methylxanthine can cause various unwanted side-effects, such as headaches, ill temper, nausea, heartburn, diarrhea, abnormally fast heart rates, hyperventilation, insomnia and even seizures. At best, methylxanthines are alternative medications for regularly occurring cases of asthma. However, methylxanthine can clearly be effected by the presence of other drugs in the bloodstream, and a physician should be consulted prior to taking it. Also, excessive amounts of methylxanthine (slow-release variants in particular) in blood can give rise to negative side-effects, so its level must be regularly monitored as well.