Caffeine Intoxication, in Which the Theophylline Level Served as an Indicator of the Treatment Course and the Caffeine Level Could Be Measured.

A 51-year-old man presented with sudden-onset palpitations and dyspnea that had started 8 h earlier. The patient was restless and tachypneic and had persistent vomiting upon arrival. His sensorium and oxygen saturation levels rapidly declined three hours after arrival, and he was placed on a ventilator. On hospitalization day 2, he was removed from the ventilator and claimed that he had consumed a large amount of energy drinks (oral caffeine intake, approximately 1 g). The theophylline level on arrival had been elevated (9.0 μg/mL). Caffeine intoxication should be considered in patients presenting with restlessness, tachypnea, frequent vomiting, lactic acidosis, and electrolyte abnormalities.