Safety Pharmacological Assessment of Oral Theophylline Administration on Respiratory Function in Sprague-Dawley Rats

In this study, we evaluated the safety pharmacological effects and potential adverse reactions of orally administered theophylline. Theophylline, a commonly used bronchodilator, is a xanthine derivative that exerts stimulatory effects on the central nervous system. Using an experimental rat model, we explored the impact of theophylline on respiratory parameters, including respiratory rate, tidal volume, and minute volume. Thirty-two 6-week-old male Sprague-Dawley rats were randomly divided into control and experimental groups. The experimental group received a single oral dose of 100 mg/kg theophylline. Respiratory parameters were measured at baseline (0 h) and at 0.5, 1, 2, 4, and 6 h post oral administration of theophylline using a whole-body plethysmograph. Oral theophylline administration significantly increased the respiratory rate and minute volume at all postdose time points compared with those in the control group, and peak values were observed at 0.5 h postadministration (P < .05). In contrast, the tidal volume remained consistent across all time points, indicating that theophylline enhances respiratory efficiency primarily by increasing the frequency of breaths rather than by altering their depth. Our study demonstrated the ability of theophylline to enhance respiratory efficiency via increased breathing frequency without affecting tidal volume, thus offering insights into the clinical significance of oral theophylline in managing chronic respiratory diseases.