What is the preferred initial antihypertensive medication for a patient with a blood pressure of 180/84 mm Hg and chronic kidney disease stage 3 with an estimated glomerular filtration rate of approximately 37 mL/min?

Antihypertensive Management for BP 180/84 mmHg with CKD Stage 3b (eGFR 37)

Start an ACE inhibitor (lisinopril 10 mg daily) as first-line therapy, titrate to the maximum tolerated dose (up to 40 mg daily), and target a blood pressure <130/80 mmHg. 1, 2, 3

First-Line Pharmacotherapy

ACE inhibitors are the mandatory first-line antihypertensive agent for CKD stage 3b patients with hypertension. 4, 1, 3 The evidence supporting this recommendation is strongest when albuminuria is present (≥30 mg/day), but ACE inhibitors remain appropriate initial therapy even without documented proteinuria given the patient's reduced kidney function. 1, 3

• Begin lisinopril 10 mg once daily (the standard initial dose for hypertension per FDA labeling). 5
• Titrate to the maximum tolerated dose (up to 40 mg daily) over 4-8 weeks, as clinical trial benefits were achieved at target doses. 1, 3
• If ACE inhibitor is not tolerated (most commonly due to dry cough), substitute an ARB (such as losartan), which provides comparable renal and cardiovascular protection. 4, 1, 2

Blood Pressure Target

Aim for <130/80 mmHg using standardized office measurement. 4, 1, 2 This target is appropriate for CKD patients regardless of albuminuria status, though the evidence is strongest when proteinuria is present. 1 The more aggressive target of <120 mmHg systolic applies only when standardized automated office BP measurement is used (5-minute rest, average of three readings) and should not be applied to routine office readings. 1

Critical Monitoring After ACE Inhibitor Initiation

Check serum creatinine and potassium 2-4 weeks after starting or increasing the ACE inhibitor dose. 1, 2, 3

• Continue the ACE inhibitor unless serum creatinine rises >30% within 4 weeks; an increase up to 30% reflects the intended hemodynamic effect of reducing intraglomerular pressure and should not prompt discontinuation. 1, 2, 3
• Manage hyperkalemia with potassium-wasting diuretics, potassium binders, or dietary restriction rather than stopping the ACE inhibitor. 1, 3
• Discontinue or reduce the ACE inhibitor only if hyperkalemia is uncontrolled despite interventions, the patient develops symptomatic hypotension, or the creatinine increase >30% persists. 1

Second-Line Therapy (When Monotherapy Insufficient)

This patient with BP 180/84 mmHg will almost certainly require multiple agents to reach target <130/80 mmHg. 4, 1 Most CKD patients need three or more antihypertensive medications. 4, 1

Add a long-acting dihydropyridine calcium channel blocker (amlodipine 5-10 mg daily) as second-line therapy when BP remains uncontrolled on maximally tolerated ACE inhibitor. 1, 2, 3 Calcium channel blockers are preferred over thiazide diuretics as the second agent in CKD stage 3b. 1, 2

Third-Line Therapy

Add a thiazide-like diuretic (chlorthalidone 12.5-25 mg daily preferred over hydrochlorothiazide) as third-line therapy. 1, 5 Thiazide diuretics remain effective at eGFR 37 mL/min and should not be automatically discontinued at this level of kidney function. 2 Loop diuretics are reserved for CKD stage 4-5 (eGFR <30 mL/min). 1

Lifestyle Modifications

• Limit dietary sodium to <2 g/day (approximately 5 g salt) to enhance antihypertensive efficacy. 1, 3
• Restrict protein intake to 0.8 g/kg/day for CKD stage 3; avoid high-protein diets >1.3 g/kg/day. 4, 1
• Encourage tobacco cessation. 1
• Promote at least 150 minutes per week of moderate-intensity physical activity. 1

Follow-Up Schedule

• Schedule clinic visits every 6-8 weeks until BP target <130/80 mmHg is achieved. 1
• Implement home BP monitoring during medication titration to prevent hypotension (systolic <110 mmHg). 1
• Once target is reached, follow up every 3-6 months with monitoring of serum creatinine, eGFR, and potassium. 1
• Assess urine albumin-to-creatinine ratio at least annually to detect new-onset albuminuria that would intensify treatment strategy. 4, 1

Critical Contraindications

Never combine an ACE inhibitor with an ARB (dual RAS blockade), as this increases the risk of hyperkalemia, hypotension, and acute kidney injury without additional benefit. 1, 2, 3 This is a strong (Class III) contraindication. 1

Patient Education: Sick-Day Management

Instruct the patient to hold or reduce antihypertensive doses during acute illnesses with vomiting, diarrhea, or reduced oral intake to prevent volume depletion and acute kidney injury. 1 Teach the patient to watch for symptoms of hypotension such as fatigue, light-headedness, or dizziness. 1

Common Pitfalls to Avoid

• Do not discontinue the ACE inhibitor for a creatinine rise <30%; this reflects the intended mechanism of action. 1, 2
• Do not apply the <120 mmHg target to routine office BP measurements; it requires standardized automated measurement. 1
• Do not withhold ACE inhibitor therapy solely because albuminuria has not been documented; the patient's reduced eGFR (37 mL/min) alone justifies ACE inhibitor use. 1, 3
• Do not use hydrochlorothiazide as monotherapy in CKD patients with proteinuria; always combine with a RAS blocker. 6