How to switch a 90-year-old patient with hypertension and aortic stenosis, currently on perindopril (Angiotensin-Converting Enzyme Inhibitor) 2.5mg daily, to an Angiotensin Receptor Blocker (ARB) due to a persistent cough?

Switching from Perindopril to an ARB in a 90-Year-Old Patient with Hypertension, Aortic Stenosis, and ACE Inhibitor-Induced Cough

For a 90-year-old patient with hypertension and aortic stenosis experiencing cough on perindopril, switch to losartan 25mg daily as initial ARB therapy, with follow-up in 2-4 weeks to assess efficacy and tolerability. 1

Rationale for Switching to an ARB

• ACE inhibitor-induced cough is a common adverse effect occurring in approximately 3.9% of patients taking perindopril, with higher risk in older patients and females 2
• ARBs provide similar cardiovascular benefits to ACE inhibitors but do not cause cough as they do not affect bradykinin metabolism, which is the primary mechanism of ACE inhibitor-induced cough 3
• ARBs are specifically recommended as an alternative in patients who are intolerant to ACE inhibitors due to cough 1
• For patients with aortic stenosis, RAS inhibition (including ARBs) may be beneficial in managing hypertension and may potentially slow valve calcification progression 4

Recommended Switching Protocol

1. Discontinue perindopril immediately

   • No washout period is required when switching directly from an ACE inhibitor to an ARB 1
   • Cough typically resolves within 1-4 weeks after discontinuation of the ACE inhibitor 3

2. Start ARB therapy:

   • Begin with losartan 25mg once daily (half the usual starting dose due to advanced age) 1
   • Alternative ARBs with their starting doses include:
     • Valsartan 40mg once daily
     • Candesartan 4mg once daily
     • Telmisartan 20mg once daily 1

3. Monitoring and follow-up:

   • Schedule follow-up in 2-4 weeks to assess:
     • Blood pressure response
     • Resolution of cough
     • Potential adverse effects 1
   • Check renal function and serum electrolytes within 1 week of starting ARB therapy 1

4. Dose titration:

   • If blood pressure remains uncontrolled and the medication is well tolerated, consider increasing to target dose after 2-4 weeks:
     • Losartan 50-100mg daily
     • Valsartan 80-160mg daily
     • Candesartan up to 32mg daily
     • Telmisartan up to 80mg daily 1

Special Considerations for This Patient

• Advanced age (90 years): Start with lower doses and titrate more slowly to avoid orthostatic hypotension and other adverse effects 1
• Aortic stenosis: Traditionally, vasodilators were used cautiously in aortic stenosis, but recent evidence suggests RAS inhibitors may be beneficial and safe in these patients 4
• Monitor closely for:
  • Hypotension, especially orthostatic
  • Worsening renal function
  • Hyperkalemia 1

Potential Complications and Management

• Hypotension: If symptomatic hypotension occurs, consider reducing the dose or adding volume if the patient is dehydrated 1
• Renal dysfunction: If creatinine rises >30% from baseline or GFR declines significantly, consider dose reduction 1
• Hyperkalemia: Monitor potassium levels, especially if the patient is on other medications that can increase potassium 1
• Inadequate BP control: If blood pressure remains uncontrolled on ARB monotherapy, consider adding a long-acting dihydropyridine calcium channel blocker (e.g., amlodipine 2.5mg) as these are safe in aortic stenosis 1, 4

Remember that ARBs are contraindicated during pregnancy and should be used with caution in patients with bilateral renal artery stenosis 1.