Switching from Perindopril to ARB for ACE Inhibitor-Induced Cough
For a 90-year-old patient with ACE inhibitor-induced cough from perindopril 2.5mg daily, losartan 25-50mg once daily is the recommended ARB replacement. 1, 2
Rationale for Switching to an ARB
- ACE inhibitor-induced cough is a well-documented class effect occurring in 5-35% of patients taking medications like perindopril 1, 3
- The cough is typically dry and associated with a tickling sensation in the throat due to accumulation of bradykinin and substance P 1
- ARBs are the preferred alternative for patients with ACE inhibitor-induced cough as they do not inhibit ACE and therefore don't cause bradykinin accumulation 1
- Clinical guidelines strongly recommend (Grade A recommendation) switching to an ARB when ACE inhibitor-induced cough occurs 1
Specific ARB Recommendation: Losartan
- Losartan is the most studied ARB for patients with ACE inhibitor-induced cough 1, 2
- Start with losartan 25mg once daily (initial dose) and titrate to 50mg once daily if needed for blood pressure control 1, 2
- FDA data shows losartan has a cough incidence similar to placebo or hydrochlorothiazide in patients with previous ACE inhibitor-induced cough 2
- In controlled trials, only 17-29% of patients with previous ACE inhibitor-induced cough experienced cough with losartan, compared to 62-69% with ACE inhibitors 2
Dosing and Monitoring Considerations
- Begin with losartan 25mg once daily as an appropriate starting dose for an elderly patient 1, 3
- Monitor blood pressure, renal function, and potassium within 1-2 weeks after initiation 1
- Pay particular attention to postural blood pressure changes in this 90-year-old patient 1
- If blood pressure control is inadequate, increase to 50mg once daily (maximum dose for elderly patients) 1, 2
Important Precautions
- Although rare, angioedema has been reported with ARBs in patients who previously experienced angioedema with ACE inhibitors; use caution during initial treatment 1
- Monitor for hypotension, especially in elderly patients who may be more sensitive to blood pressure-lowering effects 2
- Assess renal function and potassium levels regularly, as ARBs can cause hyperkalemia and worsening renal function similar to ACE inhibitors 1
- Ensure the cough resolves after switching to losartan; if it persists, investigate other causes of cough common in elderly patients 3
Alternative ARBs if Losartan is Not Tolerated
- Candesartan 4-8mg once daily (initial dose) up to 32mg once daily (maximum dose) 1
- Valsartan 20-40mg twice daily (initial dose) up to 160mg twice daily (maximum dose) 1
These alternatives should only be considered if losartan is not tolerated, as losartan has the most robust evidence for replacing ACE inhibitors in patients with ACE inhibitor-induced cough 1, 2.