What is the first-line treatment for this patient? A 23-year-old male has experienced multiple episodes over 3 years where he wakes up in the morning after a heavy evening meal unable to move his limbs, with normal bowel/bladder function, swallowing, and breathing. Episodes last several days and have recurred 5 times. This morning, he again developed limb paralysis. Examination shows normal cranial nerves, limb muscle strength of grade I, hypoactive reflexes, no pathological reflexes, and normal sensation.