Which effect is associated with theophylline?

Which effect is associated with theophylline?

• A. CNS stimulation
• B. Tachycardia
• C. Dilation of pulmonary blood vessels
• D. Sedation

Answer: (A)

Theophylline is a methylxanthine that works by inhibiting phosphodiesterase and blocking adenosine receptors. This dual action leads to bronchodilation (via increased cAMP in airway smooth muscle) and also to central nervous system stimulation because adenosine’s normal sedative effects in the brain are reduced.

CNS stimulation is the most characteristic and expected effect linked to theophylline. It can manifest as wakefulness, restlessness, and, at higher levels, irritability or seizures. While tachycardia can occur due to overall stimulatory effects, the classic and defining association you’d recall for theophylline is CNS stimulation. Sedation would be opposite to its typical CNS effects, and dilation of pulmonary blood vessels is not the primary, defining outcome here—the drug mainly relaxes bronchial smooth muscle to relieve bronchospasm.