In patients with renal dysfunction, how should ACE inhibitors or ARBs be managed?

• A. Discontinue if hyperkalemia occurs
• B. Do not monitor labs
• C. Monitor creatinine and potassium; adjust dose or discontinue if hyperkalemia or creatinine rise significantly
• D. Increase dose

Answer: (C)

The key idea is that in kidney dysfunction, ACE inhibitors or ARBs require careful lab monitoring because they can affect both kidney function and potassium levels. Blocking the renin–angiotensin system reduces pressure in the glomerulus, which can lower GFR and cause creatinine to rise. It also reduces aldosterone, increasing potassium retention and the risk of hyperkalemia.

Therefore, the best approach is to monitor kidney function and potassium after starting therapy or after a dose change, and adjust the dose or discontinue if the creatinine rises significantly or potassium becomes dangerously high. Practical thresholds include watching for a creatinine increase from baseline of about 30% or more (or an absolute rise that concerns the patient’s baseline) and a potassium level that climbs above roughly 5.5–6.0 mEq/L, at which point dose reduction or stopping the drug is indicated. Regular follow-up and awareness of interacting factors (dehydration, NSAIDs, potassium supplements, other agents affecting potassium) help manage safety while preserving any potential benefits.