Potassium can kill a patient quickly, so every drug in this lecture is sorted by whether it lowers or raises it, why, and what that means when drugs are combined.
| Drug or class | Effect on potassium | Why | Consequence and what to watch | Source |
|---|---|---|---|---|
| Loop diuretics | Lowers (hypokalemia) | Increased potassium excretion | Cardiac arrhythmias; raises digoxin toxicity risk, especially with low magnesium | L9 slide 13 slide 18 slide 19 |
| Thiazide diuretics | Lowers | Increased potassium and magnesium excretion | Keep potassium above 4.0 mEq/L with digoxin | L9 slide 22 slide 26 slide 29 |
| Carbonic anhydrase inhibitors | Lowers | Short-term increase in sodium and potassium excretion | Potassium depletion with metabolic acidosis | L9 slide 43 slide 39 |
| Potassium-sparing diuretics (amiloride, triamterene) | Raises (hyperkalemia) | Sodium channel block lowers the gradient for potassium secretion | Caution with ACE inhibitors, angiotensin blockers and potassium supplements | L9 slide 33 slide 30 |
| Aldosterone antagonists (spironolactone, eplerenone) | Raises (hyperkalemia) | Blocks aldosterone, so potassium loss falls | Heart failure patients are not eligible if potassium is above 5 or creatinine above 2.5 | L9 slide 38 slide 36 slide 73 |
| ACE inhibitors | Raises | Listed adverse effect of the class. (Added background: less angiotensin II means less aldosterone and less potassium excretion.) | Check potassium in heart failure, especially with loops, potassium-sparing drugs or supplements | L9 slide 56 |
| Sacubitril-valsartan | Raises | Contains valsartan, an angiotensin receptor blocker. (Added background: this lowers aldosterone activity.) | Hyperkalemia is one of its common adverse effects | L9 slide 81 |
| Digoxin | No usual effect on potassium at therapeutic levels, but low potassium raises toxicity risk | Electrolyte disturbances make the heart more sensitive | Low potassium and magnesium and high calcium raise the risk of arrhythmias | L9 slide 71 slide 19 slide 29 |