Hypertension Management Complicated by Hyperkalemia: What's your Rx?
RAAS-I, that is, Renin Angiotensin Aldosterone System Inhibitors, are an integral part of any therapeutic regimen designed to treat hypertension and heart failure frequently accompanied by chronic kidney disease (CKD). RAAS-I include angiotensin converting enzyme inhibitors, angiotensin receptor blockers, direct renin inhibitors, and aldosterone receptor antagonists. Examples of these agents, respectively by class are: lisinopril, valsartan, aliskiren, and spironolactone. Despite RAAS-I efficacy, the development of hyperkalemia is a critical downside to their titration and therapeutic effectiveness in selected populations.
Let’s review a clinical case that addresses newer approaches to the prescription of RAAS-I and incremental dosing in the context of hyperkalemia.
You are caring for a 65-year-old patient with hypertension, systolic dysfunction (non-ischemic, ejection fraction 35%), and CKD 3 (GFR 44 cc/min). Blood pressure is above target (158/102 mm/Hg) on a regimen of lisinopril 10 mg/day, hydrochlorothiazide 25 mg/day, and amlodipine 5 mg/day. You consider increasing lisinopril, but the patient’s potassium increased from 4.2 to 4.6 meQ/L after you initiated therapy with 10 mg of lisinopril a few months ago. You are concerned that your patient may become hyperkalemic if you go from 10 to 20 mg of lisinopril.
1. Which of the following characteristics are the strongest predictors of hyperkalemia developing on RAAS-I (you may choose more than 1):
A. A serum potassium value > 4.5 meQ/L on an appropriate diuretic prior to starting RAAS-I.
B. A GFR of ≤ 45 cc/minute
C. A decrease in GFR of > 30% after RAAS-I therapy is initiated.
D. Prior history of resistant hypertension.