What medications lower potassium?

The medicine most likely to drain your potassium is the water pill. MedlinePlus lists medicines such as diuretics among the common causes of low blood potassium, alongside diarrhea, vomiting, laxative overuse, and some antibiotics at high levels. Diuretics make the kidneys excrete more water, and potassium rides out with it, which is why everyone on a loop or thiazide diuretic gets periodic blood tests, and why the fix menu MedlinePlus describes includes switching to a potassium-sparing form of diuretic or prescribing extra potassium to take by mouth. The other drug-adjacent causes: prolonged steroid courses and anything causing prolonged vomiting or diarrhea, since gut losses deplete potassium fast. Why a low number matters: potassium runs your heart's electrical system, so a small drop is usually symptom-free but a larger one causes weakness, cramps, constipation, and in serious cases dangerous rhythm problems, which is the entire reason the monitoring exists. What to do: take the monitoring blood tests seriously; learn the cluster if you are on a diuretic, weakness, cramps, palpitations; never self-start potassium, because too much is as dangerous as too little; and report vomiting or diarrhea promptly on these drugs, since a stomach bug can tip a borderline level.