Which of the following describes the signs of theophylline toxicity?

• A. CNS stimulation like HA, insomnia, and seizures
• B. N/V
• C. Cardiac toxicity
• D. All of the above

Answer: (D)

The key idea is that theophylline toxicity hits multiple body systems because this methylxanthine has a narrow therapeutic window and acts as a CNS stimulant with cardiac and GI effects. When the drug level rises, it can cause CNS stimulation—headache, insomnia, restlessness, and it can progress to seizures. It also irritates the stomach, producing nausea and vomiting. In the heart, it can cause tachycardia and arrhythmias, and in some cases hypotension. Because all of these areas can be affected, the option that includes CNS symptoms, GI symptoms, and cardiac symptoms best describes toxicity. In practice, recognizing this wide-ranging presentation is crucial, as toxicity requires stopping the drug and managing symptoms promptly.