Isoproterenol Inhalation Preparations labeling warns about what adverse effect with repeated, excessive use?

• A. Occasional patients develop severe paradoxical airway resistance with repeated, excessive use
• B. The drug has no adverse effects
• C. It is safe in all COPD
• D. It should be used as chronic therapy

Answer: (A)

Overuse of bronchodilators can paradoxically worsen airway narrowing. Isoproterenol inhalation, being a nonselective beta-adrenergic agonist, can irritate the airways if used repeatedly and excessively, leading to severe paradoxical airway resistance. The labeling reflects this risk, warning users not to rely on it chronically or in high amounts. The other statements are not accurate: the drug does have adverse effects, it isn’t safe for all COPD patients, and it isn’t intended for chronic therapy.