Objective: Dipyrone (Novalgin) is an effective analgesic, antipyretic agent also with spasmolytic effects on various types of smooth muscles. It has recently been reported that dipyrone relaxes tracheal smooth muscle of guinea pig. In this present study, we aimed to investigate whether this and previously reported in vitro results have any consequences on the respiratory function of normal healthy volunteers and chronic obstructive pulmonary disease (COPD) patients.
Methods: In this one-centered, non-randomized, non-comparative, open labelled study, 15 normal healthy volunteers and 15 stable COPD patients, with partially reversible bronchospasm, diagnosed according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria were enrolled in the study at the time they had any indication of dipyrone use. The spirometric tests were performed by a portable notebook and Medikro Spiro2000 spirometry programme-software 1.6 version, before 30, 60, 90, and 120 min after 20 mg/kg of orally dipyrone intake. Groups were compared with the General Linear Model Repeated Measures analysis of variance.
Results: None of the spirometric parameters evaluated showed any significant differences when compared with the baseline values in both groups.
Conclusion: While dipyrone had no bronchodilator effects on either COPD patients or normal volunteers, it also did not impair the spirometric parameters. Since COPD is a disease characterized by a progressive and largely irreversible airflow limitation, dipyrone has no observable bronchodilator effect. However, since dipyrone does not impair the pulmonary function, it can be used safely in COPD patients when there is an indication.