Can I increase losartan (angiotensin II receptor antagonist) to 100mg in a patient with impaired renal function?

Increasing Losartan Dosage in a Patient with Impaired Renal Function

Yes, you can increase losartan to 100mg in this patient with an eGFR of 55 mL/min/1.73m² (CKD stage 3a), as this level of renal impairment does not require dose adjustment for losartan. 1, 2

Assessment of Current Renal Function

• The patient has mild to moderate renal impairment with:
  • Creatinine of 1.39 mg/dL (elevated) 1
  • eGFR of 55 mL/min/1.73m² (mildly reduced) 1
  • Normal electrolytes (sodium 140 mmol/L, potassium 3.9 mmol/L) 1

Losartan Dosing in Renal Impairment

• According to ACC/AHA hypertension guidelines, losartan's standard dosing range is 50-100 mg daily 1
• Losartan does not require dose adjustment in patients with mild to moderate renal impairment 2
• FDA labeling specifically states: "No dose adjustment is necessary in patients with renal impairment unless a patient with renal impairment is also volume depleted" 2
• Only patients with severe renal impairment (GFR <30 mL/min) require special consideration for ARBs 1

Monitoring Recommendations

• Monitor serum creatinine and potassium within 2-4 weeks after increasing the dose 1
• Pay particular attention to potassium levels, as there is an increased risk of hyperkalemia with ARBs in patients with CKD 1
• Regular monitoring of electrolyte balance and serum creatinine is recommended with losartan use in renal impairment 1

Dosing Strategy

• Increase losartan from current dose to 100 mg daily (maximum recommended dose) 1
• This can be administered as a once-daily dose or split into two doses (e.g., 50 mg twice daily) 3
• The dose can be taken without regard to meals 3

Benefits of Optimal ARB Dosing

• ACC/AHA guidelines recommend titrating to target doses for optimal cardiovascular and renal protection 1
• Achieving at least 50% of target dose (50 mg for losartan) is associated with improved outcomes 1
• Losartan at 100 mg daily provides better 24-hour blood pressure control than 50 mg 3

Precautions

• Avoid combining with ACE inhibitors or direct renin inhibitors due to increased risk of hyperkalemia and hypotension 1
• Be cautious in patients with bilateral renal artery stenosis, as ARBs can cause acute renal failure in these patients 4
• If the patient develops significant hyperkalemia (>6 mEq/L) or worsening renal function, consider reducing the dose or discontinuing losartan 1, 5

Evidence for ARBs in Renal Impairment

• Studies have shown that losartan is well-tolerated in patients with various degrees of renal insufficiency 5
• Some evidence suggests losartan may help retard the progression of renal insufficiency 6, 7
• Losartan has been shown to reduce proteinuria in patients with renal disease 6, 7

In conclusion, increasing losartan to 100 mg daily is appropriate for this patient with an eGFR of 55 mL/min/1.73m². The patient's renal function should be monitored, but dose adjustment is not required at this level of renal impairment.