Alkalosis (each 0.10 rise in pH causes 0.5 decrease)
Insulin
Beta agonists<unk>  periodic paralysis
Special diets or those low in potassium
Chronic alcohol abuse
Fasting
Eating disorders
GI
Vomiting, diarrhea, fistula
Renal
Diuretics
Osmotic diuresis (late-presenting DKA)
Hyperaldosteronism
Hypercalcemia
Hypomagnesemia
Increased sweat loss
Heavy exercise
Heat stroke
Fever
Vomiting, diarrhea, fistula
Diuretics
Osmotic diuresis (late-presenting DKA)
Hyperaldosteronism
Hypercalcemia
Hypomagnesemia
Heavy exercise
Heat stroke
Fever
Penicillins
Lithium
L-dopa
Theophylline, methylxanthines (e.g. caffeine
Insulin
Barium
Quinine
Catecholamines
Acute leukemia and lymphomas
Recovery from megaloblastic anemia
Hypothermia (accidental or induced)
Hypokalemia
Alkalosis 
Hyponatremia
Insulin
Hypernatremia
Beta agonists
Hyperkalemia
Hypokalemic periodic paralysis