Background: Inhaled corticosteroid (ICS) and long-acting beta2-agonists (LABA) combination is an effective treatment for asthma. Oral bronchodilators might be used as an adjunctive treatment especially in patients with uncontrolled asthma or poor inhalation technique.

Aims and objectives: This study aimed to compare the bronchodilator effect between oral doxofylline and procaterol in adults with asthma.

Methods: A crossover randomized controlled trial was conducted in a university hospital, Thailand. Asthmatic patients aged 18 years or older with ICS/LABA treatment were included. Each patient received 2 weeks of treatment with either doxofylline or procaterol separated by a 1-week washout period. Pulmonary functions assessed by spirometry, Asthma Control Questionnaire-5 (ACQ-5) scores, exacerbation rates, and adverse events were recorded.

Results: A total of 21 patients were randomly allocated to either group. Mean age was 53.0±14.8 years. ACQ-5 scores were 1.38±1.1. After 2-week treatment, ACQ-5 scores, and pulmonary functions changes from baseline were not significantly different between two groups. However, there were significant improvements in ACQ-5 scores after treatment in both groups (mean change: -0.381± 0.740, P=0.029 and -0.476± 0.873, P=0.021 for the doxofylline and the procaterol groups, respectively). Asthma exacerbation was not found. Patients in the doxofylline group had each one of dizziness, headache, and insomnia, whereas eight in procaterol group had palpitation.

Conclusions: Doxofylline and procaterol can improve asthma symptoms, though they are not able to enhance lung functions. These oral bronchodilators might be used as an add-on therapy for asthma treatment.