If you have ever had a patient that has had a substantially elevated potassium level, you have likely been very nervous about their medication list. I really start to get concerned when I see levels above 6 mEq/L. There are numerous drugs that affect potassium that you should be aware of. I wanted to give you a list of common drugs that cause hyperkalemia and ones that I see in my practice.
Common Drugs That Cause Hyperkalemia
ACE Inhibitors and ARBs
With a huge role in the management of hypertension, ACE inhibitors and ARBs will likely be the most common medication in your practice that can cause hyperkalemia.
The downstream effects of ACE Inhibitors leads to a reduction in aldosterone. Aldosterone plays an important role in causing potassium excretion. By having less aldosterone, it leads to reduced excretion and potentially hyperkalemia. That same effect of reduced aldosterone activity can be caused by both ACE inhibitors, ARBs, and aldosterone antagonists (see next).
Aldosterone antagonists play a significant role in managing hypertension and are also a class of drugs that can be used to help with edema, ascites, and heart failure. Use is common and this class can also be commonly used in combination with ACE Inhibitors or ARBs. While there can be significant benefits from concomitant use, using these drugs in combination can strongly increase the risk for hyperkalemia.
I have seen patients use supplements on their own without it being listed on their medication list. It is critical to ask about supplements. On rare occasions, I have also seen this missed on medication reconciliation. The most common situation where I’ve seen potassium supplements cause hyperkalemia is where a patient stops taking a loop or thiazide diuretic and continues to take their prescribed supplement.
Trimethoprim is an antibiotic, most often used in combination with sulfamethoxazole. This drug is well-known to cause hyperkalemia. We had an excellent guest post, case study on this quite a while ago.
It has been a while since I’ve seen this medication used, but it is classified as a potassium-sparing diuretic. Amiloride antagonizes sodium channels in the distal convoluted tubule (DCT) and collecting duct which inhibits sodium reabsorption. Because of this action and an alteration in sodium concentrations, this slows the activity of Na+/K+ATPase which can ultimately lead to higher potassium concentrations in the blood.
Heparin can also have some aldosterone suppressing activity. The extent and frequency of hyperkalemia are likely going to be less than with ACE inhibitors, ARBs, and aldosterone antagonists, but it is worth it to mention this drug. Keep an extra close eye on those patients who may already be at risk for hyperkalemia (i.e. renal disease or concomitant drugs that cause hyperkalemia).
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