What is the best initial antihypertensive medication for an elderly patient with impaired renal function (GFR 47) and elevated creatinine level (1.04)?

Initial Antihypertensive Medication for Elderly Patient with Stage 3 CKD

Start with an ACE inhibitor (such as lisinopril 2.5-5 mg daily) or an ARB if ACE inhibitor is not tolerated, as this patient with GFR 47 has chronic kidney disease and should be treated with a renin-angiotensin system blocker as first-line therapy. 1

Rationale for ACE Inhibitor/ARB as First-Line

• The 2017 ACC/AHA guidelines explicitly recommend ACE inhibitors or ARBs as preferred agents for patients with CKD (defined as stage 3 or higher, which includes this patient with GFR 47). 1

• This recommendation applies regardless of whether albuminuria is present, though ACE inhibitors/ARBs are particularly important if albuminuria ≥300 mg/day is documented. 1

• The patient's elderly status does not contraindicate this approach—SPRINT data showed that intensive BP treatment benefited even frail elderly patients ≥75 years with CKD, with no difference in kidney outcomes between intensive and standard therapy groups. 1

Specific Dosing Recommendations for Renal Impairment

With a GFR of 47 mL/min (Stage 3a CKD), start lisinopril at 5 mg once daily, which is half the usual starting dose for hypertension. 2

• The FDA label for lisinopril specifies that in patients with creatinine clearance ≥30 mL/min and ≤60 mL/min, the initial dose should be reduced to half the usual recommended dose (5 mg for hypertension instead of 10 mg). 2

• This can be uptitrated as tolerated to a maximum of 40 mg daily, with careful monitoring. 2

Critical Monitoring Parameters

Check renal function and serum potassium within 1-2 weeks of initiating ACE inhibitor therapy, then with each dose increase, and at least yearly thereafter. 1

• A 10-25% increase in serum creatinine may occur and is expected due to hemodynamic effects on intraglomerular pressure—this is generally acceptable and may be reversible. 1

• However, creatinine increases >30% warrant investigation for other causes including volume depletion, nephrotoxic agents, or renovascular disease. 1

• ACE inhibitors are associated with hyperkalemia risk, particularly in elderly patients with diabetes or CKD, so potassium monitoring is essential. 1

Blood Pressure Target

Target BP should be <130/80 mmHg in this patient with CKD, based on SPRINT evidence showing cardiovascular and mortality benefits from intensive BP control in the CKD subgroup. 1

• The patient can be assumed to have ≥10% 10-year ASCVD risk given the presence of CKD, placing them in the high-risk category requiring treatment initiation at BP ≥130/80 mmHg. 1

• Use incremental BP reduction with careful monitoring of physical and kidney function, particularly given the patient's elderly status. 1

Alternative if ACE Inhibitor Not Tolerated

If the patient develops intolerable cough or angioedema with an ACE inhibitor, switch to an ARB (such as losartan 25-50 mg daily). 1

• ARBs have been shown to be noninferior to ACE inhibitors in clinical trials and carry similar monitoring requirements. 1

• Never combine an ACE inhibitor with an ARB—this combination is contraindicated due to demonstrated harms including increased hyperkalemia and hypotension without additional benefit. 1

When to Add Additional Agents

If BP remains uncontrolled on maximally tolerated ACE inhibitor/ARB monotherapy:

• Add a thiazide-like diuretic (chlorthalidone 12.5 mg daily) or a dihydropyridine calcium channel blocker (amlodipine 5 mg daily) as second-line therapy. 1, 3

• Thiazide-like diuretics (chlorthalidone, indapamide) remain effective even with moderate renal impairment (GFR >30 mL/min), unlike traditional thiazides which lose efficacy below GFR 30. 3

• If adding a diuretic, monitor electrolytes within 1-2 weeks of initiation due to hypokalemia risk. 1

Common Pitfalls to Avoid

• Do not rely solely on serum creatinine of 1.04 to assume normal renal function—41% of elderly patients with renal impairment have normal serum creatinine due to decreased muscle mass. 4

• Do not use the combination of ACE inhibitor + ARB or ACE inhibitor/ARB + direct renin inhibitor, as these are contraindicated. 1

• Do not avoid ACE inhibitors/ARBs in elderly patients with CKD out of concern for adverse effects—the SPRINT elderly subgroup data support their use even in frail patients. 1