A Study of the Safety and Tolerance of Regadenoson in Subjects With Asthma or Chronic Obstructive Pulmonary Disease

Inclusion Criteria: * Subject has asthma or stable chronic obstructive pulmonary disease (COPD). * Subject has a diagnosis of coronary artery disease (CAD) or risk factors for CAD as determined by a current medical diagnosis of at least 2 of the following conditions: Type 2 diabetes, hypertension, hypercholesterolemia, current or history of cigarette smoking (minimum 10 pack-years exposure) or obesity Body Mass Index (BMI \> 30). * Subject must abstain from smoking 3 hours prior and 8 hours post study drug administration. * Subject must abstain from any intake of foods and beverages containing a methylated xanthine derivative (i.e. caffeine, theobromine, or methylxanthine) within 12 hours prior to study drug administration through the Follow-Up visit, as these foods may reduce the effects of regadenoson. * Subject is able to safely abstain from theophylline for 12 hours prior to the Day 1 visit, as determined by the Investigator * Asthma subject's frequency and severity of symptoms have remained unchanged within 30 days prior to study drug administration * Asthma subject has FEV1 ≥60% predicted * COPD subject has FEV1/FVC \< 0.70 Exclusion Criteria: * Female subject who is pregnant, lactating or of childbearing potential who refuses to use a medically acceptable form of contraception until the Follow-Up visit is complete. * Subject started on a course of corticosteroids, steroid combination with long-acting Beta2-agonist (LABA) (oral or inhaled) or anticholinergic, or has undergone a change in dose of such medications ≤ 30 days prior to study drug administration (subject on a stable dose of such medications for \> 30 days prior to study drug administration is allowed). * Subject started leukotriene antagonists (e.g., montelukast), cromones (e.g., cromolyn sodium) or 5-lipoxygenase antagonists (e.g. zileuton or zyflo) or has undergone a change in dose of medications in these drug classes ≤ 7 days prior to study drug administration (subject on a stable dose of these medications for \> 7 days prior to study drug administration is allowed). * Subject has a history of second or third degree heart block or sinus node dysfunction unless the subject has a functioning pacemaker. * Subject has symptomatic hypotension (temporary and reversible conditions that no longer exist are allowed). * Subject is allergic or intolerant to aminophylline. * Subject has had a respiratory infection within 2 weeks prior to randomization. * Subject has had surgery within 3 months prior to randomization.