What adjustments should be made to the current antihypertensive regimen in a patient with impaired renal function?

Antihypertensive Regimen Adjustment for Elevated Creatinine (2.1 mg/dL)

When creatinine is elevated to 2.1 mg/dL, the ARB (valsartan) should be temporarily discontinued or reduced by 50%, while maintaining amlodipine and reducing hydrochlorothiazide to 12.5 mg daily. 1

Medication-Specific Adjustments

ARB/ACE Inhibitor Adjustment

• Temporarily discontinue or reduce ARB (valsartan) by 50% due to elevated creatinine 1
• ACE inhibitors and ARBs should be avoided in patients with creatinine >2.5 mg/dL in men or >2.0 mg/dL in women 2
• The patient's creatinine of 2.1 mg/dL is approaching this threshold, warranting immediate adjustment

Diuretic Adjustment

• Reduce hydrochlorothiazide from 25 mg to 12.5 mg daily 1
• Consider switching to a loop diuretic if diuresis is still required, as thiazides lose effectiveness when creatinine clearance is <40 mL/min 2
• Loop diuretics are preferred in patients with impaired renal function as they maintain efficacy unless renal function is severely impaired 2

Calcium Channel Blocker

• Maintain amlodipine at current dose 1
• Calcium channel blockers are generally safe in renal impairment and may become the preferred agent in this setting 1, 3

Monitoring Protocol

1. Check BUN, creatinine, and electrolytes (especially potassium) within 1-2 weeks after medication changes 1
2. Monitor blood pressure closely to ensure adequate control despite medication changes
3. Continue renal function monitoring every 1-2 weeks until stable, then every 1-3 months 1
4. Target blood pressure should be adjusted to 130-139 mmHg systolic in CKD patients 2

Alternative Strategies if BP Control Inadequate

• If additional antihypertensive effect is needed after ARB discontinuation, consider increasing amlodipine dose 1, 3
• Consider adding a beta-blocker like nebivolol at a reduced dose of 2.5 mg daily (standard dose is 5 mg) due to severe renal impairment 4
• Non-dihydropyridine calcium channel blockers may have additional renoprotective effects 3, 5

Important Considerations and Pitfalls

• Avoid combination of ACE inhibitors and ARBs as this may increase adverse events 2
• Be vigilant for hyperkalemia, which occurs in approximately one-third of patients with renal impairment on ACE inhibitors/ARBs 6
• Watch for orthostatic hypotension, especially after medication changes, as it can occur with greater frequency in patients with renal impairment 1, 7
• Consider underlying causes of renal dysfunction, including possible renovascular hypertension, which would contraindicate ACE inhibitors/ARBs 1

This approach prioritizes renal protection while maintaining blood pressure control, with medication adjustments specifically tailored to the degree of renal impairment indicated by the creatinine level of 2.1 mg/dL.