Best Drugs for Avoiding Paradoxical Bronchospasm During Spirometry

Asthma could be diagnosed by its characteristic presentation. Spirometry can help the diagnosis by revealing post-bronchodilator response. Classically, salbutamol (albuterol) is used for evaluating post-bronchodilator response. This drug causes paradoxical bronchospasm in less than 10% of asthmatic patients. This study aimed to evaluate the frequency of paradoxical bronchospasm with salbutamol during spirometry and compare it with other drugs that did not reveal paradoxical bronchospasm such as levalbuterol and ipratropium. One hundred-Ninety two asthmatic subjects were entered in this clinical trial. All patients showed clinical manifestations of asthma and revealed obstructive pattern during spirometry. They were randomly assigned into three groups of drugs included: salbutamol, levalbuterol and ipratropium. Two puffs of these drugs were administered via a spacer and patients waited for fifteen minutes for the maximal effect to take place. Then spirometry was obtained again and post-bronchodilator FEV1 and its alterations were compared among the three groups. The mean± SD age of patients was 49.40±17.4 years; the mean age, demographic data, clinical findings and spirometry results showed no significant difference among groups. FEV1 percent of predicted was 58.6± 19.5 which proved that most subjects were suffering from severe asthma. Improvement of FEV1 by salbutamol (22.2±3%) and levalbuterol (16±18%) was significantly more compared with ipratropium (9.4±11%) (t=2.5, P=0.01 and t=2.2, P=0.01, respectively). Paradoxical bronchospasm (more than 12% decrease in FEV1) was seen in two (3%), one (1.5%) and four (6%) subjects of salbutamol, ipratropium and levalbuterol groups, respectively. Regarding clinical improvement, levalbuterol resulted in the higher frequency of clinical improvement compared to salbutamol and ipratropium. With the dosage recommended for reversibility testing during spirometry, salbutamol showed comparable bronchodilator response and paradoxical bronchospasm frequency compared to levalbuterol and ipratropium.)