Effect of oral aminophylline on pulmonary function improvement and tolerability in different age groups of COPD patients.

BACKGROUND Aminophylline therapy in elderly patients with COPD is rarely studied. This study attempted to explore the symptoms, pulmonary function improvement, and adverse events related to aminophylline therapy in COPD patients of different age groups. METHODS AND RESULTS We designed a 10-week prospective study. Two groups of COPD patients were classified based on age (30 patients in group 1, 55 to 74 years old; 30 patients in group 2, 75 to 90 years old), with matched disease severity. After stopping all methylxanthines for 2 weeks in the washout period, therapy began with long-acting 225-mg aminophylline compounds bid po for 8 weeks. Pulmonary functions, respiratory symptoms, and laboratory examinations were checked at the initial visit and at every 4-week visit. After aminophylline therapy, the drug serum level showed no significant difference in either group (9.73 +/- 6.35 mg/dL [+/- SD] in group 1 and 7.82 +/- 6.68 mg/dL in group 2, p = 0.359). Improvements of FEV1 and FVC were noted in both groups; however, there was no significant difference. Peak expiratory flow rate (PEFR) was significantly improved in group 1 but not in group 2 (group 1, from 3.51 to 3.97 L/s, p < 0.05; group 2, from 2.78 to 3.08 L/s, p > 0.05). The degree of improvement in symptom scores was not different between the groups, except there was significantly less chest tightness in group 2 (from 0.79 +/- 0.74 to 0.40 +/- 0.50, p < 0.05). Electrolyte imbalance and arrhythmia did not appear in either group. CONCLUSIONS Our study demonstrated that the safety and drug concentration of aminophylline at a standard dose are not different in the sixth to ninth decades of COPD patients. Younger patients have more improvement in PEFR than older patients; however, older COPD patients have more symptoms relief in chest tightness after aminophylline therapy.