Theophylline is a drug that can expand the bronchial tubes, theophylline due to the metabolic time is particularly short, the metabolism is particularly fast, eaten very soon after the pharmacological effects of the full play, in the dosage form should be adjusted accordingly. Theophylline slow-release tablets are made of theophylline into a slow-release tablets, into the gastrointestinal tract is not immediately dissolved, with the passage of time, the amount of medicine gradually released, so that the body has been the maintenance of the drug to ensure that a certain effect of the drug can make people in a fairly long period of time, to play the effect of asthma, cough. So theophylline extended-release tablets, especially for the elderly, patients with cough and asthma, can play a cough, asthma, phlegm effect, is very suitable for the elderly to use a kind of drugs.