If someone's potassium is high how can reduce it?

Depends: It depends on the cause. If it is from taking too much supplemental potassium, stopping the extra potassium will allow the body to regulate itself. If it is from kidney disease there are some medications like furosemide that will cause potassium to be lost in the urine at a higher rate. If the potassium is very high and the kidney function is poor, dialysis may be needed.

Reducing potassium: First, eliminate high potassium foods from diet, tomato, potato, citrus, peaches, melons, pomegranate are a few. An oral purgative is available, a resin. Diuretic therapy also eliminates potassium. And make sure no meds are being taken that contain potassium or that might elevate potassium, such as ACE INHIBITORS, BETA BLOCKERS, ANGIOTENSIN BLOCKERS.