A client with chronic obstructive pulmonary disease (COPD) is prescribed theophylline. Which adverse effect should the nurse monitor for that indicates toxicity?
Correct Answer: A
Rationale: The correct answer is A: Tachycardia. Tachycardia is a common sign of theophylline toxicity. The nurse should monitor the client for an increased heart rate, as it can indicate a dangerous level of theophylline in the body. Prompt medical attention is required if tachycardia is observed to prevent further complications. Choices B, C, and D are incorrect because constipation, drowsiness, and tremors are not typically associated with theophylline toxicity. While theophylline can cause gastrointestinal upset or central nervous system effects, tachycardia is a more specific and serious indicator of toxicity that requires immediate attention.