A nurse is caring for a client who is receiving morphine intravenously. Which of the following findings indicates the client is experiencing morphine toxicity?

Bradypnea (respiratory rate below 12/min) is the hallmark sign of opioid toxicity. Morphine overdose causes respiratory depression by binding to opioid receptors in the brainstem, which controls breathing. The opioid reversal agent naloxone must be administered immediately. Fluid retention, prolonged QT interval, and hyperactive reflexes are not associated with morphine toxicity — decreased reflexes and sedation are expected with toxicity.