Aminophylline Products | Cleanchem - Aminophylline is a bronchodilator used to treat asthma, COPD, and apnea in premature infants. It is a combination of theophylline and ethylenediamine, which relaxes bronchial smooth muscle and increases diaphragmatic contractility. Its therapeutic range is narrow, requiring careful monitoring of blood levels. Side effects include nausea, arrhythmias, and seizures.