Switch to Losartan, Not Another ACE Inhibitor
For a patient with ACE inhibitor-induced cough from lisinopril, you should switch to losartan (an ARB) rather than trying another ACE inhibitor. This is a Grade A recommendation with good quality evidence and substantial net benefit 1.
Why Losartan is the Clear Choice
The evidence is unequivocal: cough is a class effect of all ACE inhibitors, meaning switching from one ACE inhibitor to another will almost certainly result in recurrence of the cough 1, 2. The mechanism involves accumulation of bradykinin and substance P due to kininase II inhibition—a property shared by all ACE inhibitors regardless of which specific agent you choose 1.
The Evidence for Losartan
Clinical trials directly comparing losartan to ACE inhibitors in patients with prior ACE inhibitor-induced cough demonstrate:
- Losartan cough incidence: 17-29% (similar to hydrochlorothiazide at 25% or placebo at 35%)
- Lisinopril cough incidence: 62-69% in the same population 3, 4
This represents a statistically significant reduction (p < 0.01) in cough occurrence 4. Losartan's mechanism—selective AT1 receptor blockade without kininase II inhibition—explains why it doesn't trigger the bradykinin-mediated cough reflex 1.
Common Pitfall to Avoid
Do not attempt switching to another ACE inhibitor (such as enalapril, ramipril, or fosinopril). While isolated case reports suggest occasional success 5, this contradicts the established understanding that cough is a class effect 2, 6. The ACCP guidelines explicitly state that "replacement by another ACE inhibitor should not be tried, since the cough will almost always recur on rechallenge" 2.
Clinical Algorithm
Discontinue lisinopril immediately - this is the only uniformly effective treatment for ACE inhibitor-induced cough 1
Wait for cough resolution - typically occurs within 1-4 weeks, though may take up to 3 months in some patients 1
Initiate losartan 50 mg once daily - this dose was used in the pivotal cough studies 3
Monitor blood pressure and angina control - ARBs provide equivalent cardiovascular protection to ACE inhibitors for hypertension and can be used in patients with coronary artery disease 7
Additional Considerations for This Patient's Angina
Since this patient also has angina, ensure comprehensive anti-anginal therapy is optimized. While losartan addresses the blood pressure/cardiovascular protection component, the angina may require:
- Beta-blockers (first-line for angina) - can be safely combined with losartan 7
- Calcium channel blockers (amlodipine or diltiazem) - also first-line options 8
- Short-acting nitrates for acute symptom relief 8
The combination of beta-blockers with ARBs (like losartan) provides complementary actions on the sympathetic nervous system and renin-angiotensin-aldosterone system, offering both blood pressure control and cardioprotection 7.
What If Cough Recurs on Losartan?
If the patient develops cough on losartan (occurs in approximately 17-29% based on trial data 3):
- This suggests the cough may not have been ACE inhibitor-related
- Investigate other causes: post-nasal drip, GERD, asthma, chronic bronchitis
- Consider alternative antihypertensive classes (calcium channel blockers, beta-blockers, thiazide diuretics)
The key message: Losartan is significantly more effective than switching to another ACE inhibitor for preventing cough recurrence while maintaining cardiovascular protection.