What adjustments should be made to a client's antihypertensive medication regimen due to impaired renal function?

Adjusting Antihypertensive Medications for Impaired Renal Function

The client's antihypertensive regimen should be modified by reducing or temporarily discontinuing the valsartan (ARB) due to the significant rise in BUN and creatinine, while maintaining amlodipine and considering a reduction in hydrochlorothiazide dose. 1

Assessment of Current Situation

The patient is currently taking:

• Valsartan 80 mg twice daily (morning and bedtime)
• Amlodipine 5 mg at 4 PM
• Hydrochlorothiazide (HCTZ) 25 mg in the morning
• BUN has increased from 25 to 35
• Creatinine has increased (exact value not specified but appears significant)

Recommended Medication Adjustments

Primary Intervention

1. Valsartan (ARB)

   • Temporarily reduce dose by 50% or discontinue due to significant rise in renal function markers
   • Renin-angiotensin system blockers (ARBs) can cause acute deterioration of renal function, especially in patients with compromised renal perfusion 2
   • Monitor renal function 1-2 weeks after dose reduction 1

2. Hydrochlorothiazide

   • Consider reducing dose from 25 mg to 12.5 mg daily
   • Thiazide diuretics can worsen renal function, especially when combined with ARBs 1
   • May need to be discontinued if renal function continues to deteriorate 1

3. Amlodipine

   • Maintain current dose of 5 mg daily
   • Calcium channel blockers are generally safe in renal impairment and may be preferred in this setting 1

Monitoring Protocol

1. Short-term monitoring (1-2 weeks):

   • Check BUN, creatinine, and electrolytes (especially potassium) 1
   • Monitor blood pressure closely to ensure adequate control despite medication changes
   • Assess for signs of volume overload or dehydration

2. Follow-up monitoring:

   • If renal function improves, consider cautious reintroduction of valsartan at a lower dose
   • If renal function stabilizes but remains impaired, consider alternative antihypertensive strategies
   • Monitor renal function every 1-2 weeks until stable, then every 1-3 months 1

Rationale for Recommendations

The rise in BUN and creatinine suggests worsening renal function which may be related to the medication regimen. According to guidelines:

• ARBs like valsartan can cause acute deterioration of renal function, particularly when combined with diuretics 2
• The European Society of Cardiology guidelines recommend reducing or discontinuing ACE inhibitors/ARBs if creatinine increases by more than 50% from baseline 1
• Thiazide diuretics can exacerbate renal dysfunction and may need dose reduction or discontinuation 1
• Calcium channel blockers like amlodipine have less impact on renal function and can be safely continued 1

Alternative Approaches If Initial Adjustments Are Insufficient

If renal function does not improve after initial adjustments:

1. Consider replacing valsartan with a calcium channel blocker if additional antihypertensive effect is needed
2. Switch from hydrochlorothiazide to a loop diuretic (e.g., low-dose furosemide) if diuresis is still required
3. Add or increase beta-blocker dose as they have been shown to be protective in patients with worsening renal function 3

Common Pitfalls to Avoid

• Don't abruptly discontinue all antihypertensive medications - this can lead to rebound hypertension
• Avoid volume depletion - ensure adequate hydration while reducing diuretic doses
• Don't ignore electrolyte imbalances - monitor potassium closely, especially if continuing ARB therapy
• Don't assume renovascular hypertension without further testing, but consider it if renal function deteriorates significantly with ARB therapy 2

This approach prioritizes preserving renal function while maintaining blood pressure control, with careful monitoring to guide subsequent adjustments.