A 28-year-old male with a history of chronic DNP (2,4-dinitrophenol) abuse for weight loss presents with progressive weakness, paresthesias in both feet, and a core temperature of 39.2°C despite ambient temperature of 22°C. He reports taking DNP capsules irregularly over the past 6 months. Neurological examination reveals distal sensory loss and diminished ankle reflexes. What is the most appropriate immediate next step in management?