breathing

what is the difference between theophylline er and theophylline cr ?

[Dr Santos]

Hi,
Theophylline ER or extended release tablets (100 mg, 200 mg, 300 mg or 450 mg of anhydrous theophylline) are recommended for chronic or long-term management and prevention of symptoms of asthma and other chronic lung diseases and may be taken in a twice a day dosing. On the other hand,  theophylline CR or controlled release tablets (400mg) may be given once daily to  provide maximum blood levels at the time of peak bronchoconstriction, whether at night or during the day. Hope this helps. Take care and regards.