How to manage hyperkalemia in a patient taking lisinopril and hydrochlorothiazide?

Management of Hyperkalemia in a Patient on Lisinopril-Hydrochlorothiazide

In this 54-year-old male with potassium 5.4 mEq/L on lisinopril-hydrochlorothiazide, you should NOT discontinue the lisinopril but instead implement dietary potassium restriction, increase monitoring frequency, and consider adding a newer potassium binder to maintain this beneficial RAAS inhibitor therapy. 1, 2

Classification and Risk Assessment

This patient's potassium of 5.4 mEq/L represents mild hyperkalemia (>5.0 to <5.5 mEq/L) 2. While this level is concerning, it does not require emergency intervention or immediate hospitalization unless ECG changes or symptoms develop 3.

Key risk factors present in this patient:

• Age 54 years (moderate risk, though <70 years is lower risk for severe progression) 4
• ACE inhibitor use (lisinopril) - a known hyperkalemia risk 5
• The hydrochlorothiazide component should theoretically provide some protection against hyperkalemia 6, but this protective effect may be insufficient 7

Immediate Assessment Steps

Obtain an ECG immediately to assess for cardiac conduction abnormalities (peaked T waves, flattened P waves, prolonged PR interval, widened QRS complex) 1, 3. This is critical even in asymptomatic patients, as cardiac effects can occur without symptoms 2.

Rule out pseudohyperkalemia by ensuring proper blood draw technique and considering repeat measurement if there was hemolysis or prolonged tourniquet time 2, 3.

Management Algorithm - Do NOT Stop the Lisinopril

The most critical pitfall to avoid is prematurely discontinuing beneficial RAAS inhibitor therapy 1, 2. Evidence shows that discontinuation of ACE inhibitors is associated with higher mortality and major adverse cardiovascular events 2. The FDA label for lisinopril states to "monitor serum potassium periodically" but does not mandate discontinuation at this level 5.

Step 1: Dietary and Medication Review

Implement strict dietary potassium restriction to <3 g/day 3:

• Eliminate high-potassium foods (bananas, oranges, tomatoes, potatoes, spinach)
• Avoid salt substitutes containing potassium 2
• Discontinue any potassium supplements if present 2

Review and eliminate other contributing medications 1:

• NSAIDs (increase hyperkalemia risk with ACE inhibitors) 5
• Potassium-sparing diuretics if any were added
• The sertraline is not a significant contributor

Note on testosterone: The patient stopped testosterone earlier in 2025, which is appropriate as it is not contributing to current hyperkalemia 1.

Step 2: Optimize Current Regimen

The hydrochlorothiazide 12.5 mg is already present and providing some protection 6. Studies show that thiazide diuretics attenuate potassium increases from ACE inhibitors 5, 6. However, you could consider:

• Increasing the hydrochlorothiazide dose to 25 mg if blood pressure control allows and renal function is adequate (eGFR >30 mL/min) 2, 1
• This increases potassium excretion without discontinuing the cardioprotective lisinopril 6

Step 3: Consider Adding a Newer Potassium Binder

Strongly consider initiating patiromer or sodium zirconium cyclosilicate (SZC) 1, 2:

• These newer agents are more effective and safer than sodium polystyrene sulfonate 1
• They allow continuation and optimization of RAAS inhibitor therapy 2
• The DIAMOND trial showed patiromer reduced hyperkalemia risk by 37% (HR 0.63) while maintaining RAAS inhibitor therapy 2
• Avoid chronic sodium polystyrene sulfonate with sorbitol due to bowel necrosis risk 1

Step 4: Monitoring Protocol

Recheck potassium within 3-7 days after implementing dietary changes and any medication adjustments 2, 1:

• ACC/AHA guidelines recommend checking potassium 72 hours to 1 week after any RAAS inhibitor dose change 2
• Then recheck at 1 week if stable 3
• Monthly monitoring for first 3 months, then every 3 months thereafter 2

More frequent monitoring is warranted if 1:

• Potassium continues to rise
• Renal function deteriorates
• Additional RAAS inhibitors are added

When to Reduce or Stop Lisinopril

Only consider dose reduction or temporary discontinuation if 2:

• Potassium rises to >5.5 mEq/L (at which point reduce dose by 50%) 2
• Potassium exceeds 6.0 mEq/L (stop temporarily) 2
• ECG changes develop 3
• Symptoms occur (muscle weakness, paresthesias) 3
• Acute kidney injury develops 5

If you must temporarily stop lisinopril, plan to rechallenge 2:

• After potassium normalizes to <5.0 mEq/L
• With close monitoring (recheck in 3-7 days)
• Consider starting a potassium binder concurrently 2
• Over 80% of patients can be rechallenged successfully without recurrent hyperkalemia 2

Special Considerations

The combination of lisinopril-hydrochlorothiazide provides complementary effects 7:

• Lisinopril blocks aldosterone, tending to retain potassium
• Hydrochlorothiazide increases potassium excretion
• This combination is generally safer than lisinopril alone regarding potassium balance 6

This patient's age (54 years) and absence of severe renal dysfunction are favorable 4:

• Patients <70 years with normal renal function rarely develop severe hyperkalemia after an initial mild episode 4
• Risk factors for progression to severe hyperkalemia include age >70 years and BUN >25 mg/dL 4

Common Pitfalls to Avoid

Do not discontinue lisinopril prematurely - this increases mortality risk 2, 1. The evidence strongly supports maintaining RAAS inhibitor therapy and managing hyperkalemia with other strategies 2.

Do not ignore the need for ECG - cardiac effects can occur without symptoms 2, 3.

Do not delay treatment while waiting for repeat labs if clinical suspicion is high or ECG changes are present 3.

Do not use chronic sodium polystyrene sulfonate - the newer binders (patiromer, SZC) are safer and more effective 1.

Do not assume the hydrochlorothiazide alone will be sufficient - this patient demonstrates that the combination may still result in hyperkalemia requiring additional intervention 8.