Psychiatryniche
A 24-year-old man admitted with a first episode of psychosis started olanzapine six days ago and had the dose increased four days ago; he has also taken sertraline unchanged for three months and drinks no alcohol. Overnight he has become mute and confused. Temperature is 39.1 degrees C, pulse 126/min, blood pressure swinging between 92/58 and 168/96 mmHg. His arms resist passive movement evenly through the whole range, the ankles show no beating when the foot is pushed up, and he is drenched in sweat. Creatine kinase is 6800 units/L (less than 200); chest X-ray and urinalysis are normal. Which one of the following is the most appropriate immediate management?