Defined as >5.5 mEq/L
Potassium secretion is proportional to flow rate and sodium delivery through distal nephron
Thus, loop & thiazide diuretics cause hypokalmia
Most common cause is hemolysis from blood draw (pseudohyperkalemia)
Thus, loop & thiazide diuretics cause hypokalmia
β blockers
Digoxin
Potassium-containing drugs
Potassium supplements
Salt substitutes
Hyperosmolar solutions (mannitol, glucose)
Suxamethonium
Intravenous cationic amino acids
Stored red blood cells (haemolysis releases potassium)
Herbal medicines (such as alfalfa, dandelion, horsetail, milkweed, and nettle)
ACE inhibitors; Angiotensin II receptor blockers
NSAIDs
Heparin
Antifungals (ketoconazole, fluconazole, itraconazole)
Cyclosporine
Tacrolimus
Spironolactone
Eplerenone
Drospirenone
Potassium sparing diuretics (amiloride, triamterene)
Trimethoprim
Pentamidine
Hyperkalemia
Pseudohyperkalemia: hemolyzed specimen, prolonged tourniquet use prior to blood draw, thrombocytosis or leukocytosis
Hyponatremia
Redistribution 
Hypernatremia
Acidemia 
Hypokalemia
Cellular breakdown: see Rhabdomyolysis/Crush syndrome, electrical/thermal burn, hemolysis, see Tumor lysis syndrome