Has the change to beta-agonists combined with oral theophylline increased cases of fatal asthma?
D000318:Adrenergic beta-Agonists / Q000008:administration & dosage*; D001249:Asthma / Q000188:drug therapy / Q000401:mortality*; D004359:Drug Therapy, Combination; D006801:Humans; D013806:Theophylline / Q000008:administration & dosage*
D000318:Adrenergic beta-Agonists; D013806:Theophylline