Critical Error in Current Regimen
You must immediately discontinue either lisinopril or losartan—combining an ACE inhibitor with an ARB is contraindicated and increases adverse events (hyperkalemia, acute kidney injury) without providing additional cardiovascular benefit. 1
Immediate Action Required
Stop the dual RAS blockade immediately. Choose to continue either lisinopril 20mg OR losartan 100mg, but never both together. 1
The combination of ACE inhibitor plus ARB violates all major guideline recommendations and exposes the patient to unnecessary harm. 1
After Correcting the Regimen: Add a Calcium Channel Blocker
Once you've discontinued one of the RAS blockers, add amlodipine 5-10mg daily as your second agent to achieve guideline-recommended dual therapy. 1
The combination of ACE inhibitor (or ARB) plus calcium channel blocker provides complementary mechanisms—vasodilation through calcium channel blockade and renin-angiotensin system inhibition—with superior blood pressure control compared to either agent alone. 1, 2
Amlodipine has a long half-life (35-50 hours) and duration of action exceeding 24 hours, maintaining BP control even with missed doses. 3
This combination is particularly beneficial for patients with chronic kidney disease, heart failure, or coronary artery disease. 1
If Blood Pressure Remains Uncontrolled on Dual Therapy
Add a thiazide-like diuretic as the third agent to achieve guideline-recommended triple therapy. 1
Chlorthalidone 12.5-25mg daily is preferred over hydrochlorothiazide due to its longer duration of action and proven cardiovascular disease reduction. 1
The combination of ACE inhibitor/ARB + calcium channel blocker + thiazide diuretic represents the evidence-based triple therapy targeting three complementary mechanisms: renin-angiotensin system blockade, vasodilation, and volume reduction. 1
Monitor serum potassium and creatinine 2-4 weeks after initiating diuretic therapy to detect potential hypokalemia or changes in renal function. 1
Target Blood Pressure and Monitoring
Target BP should be <140/90 mmHg minimum, ideally <130/80 mmHg for higher-risk patients (diabetes, chronic kidney disease, established cardiovascular disease). 1
Reassess blood pressure within 2-4 weeks after medication adjustment, with the goal of achieving target BP within 3 months. 1
Confirm elevated readings with home blood pressure monitoring (target <135/85 mmHg) or 24-hour ambulatory monitoring to rule out white coat hypertension. 1
If Blood Pressure Remains Uncontrolled on Triple Therapy
Add spironolactone 25-50mg daily as the preferred fourth-line agent for resistant hypertension. 1
Spironolactone provides additional BP reductions when added to triple therapy, addressing occult volume expansion that commonly underlies treatment resistance. 1
Monitor potassium closely when adding spironolactone to an ACE inhibitor or ARB, as hyperkalemia risk is significant. 1
Critical Pitfalls to Avoid
Never combine an ACE inhibitor with an ARB—this is the most important takeaway from your current situation. 1
Do not add a beta-blocker as the third agent unless there are compelling indications (angina, post-MI, heart failure with reduced ejection fraction, or need for heart rate control). 1
Verify medication adherence before escalating therapy, as non-adherence is the most common cause of apparent treatment resistance. 1
Rule out secondary hypertension if BP remains severely elevated—look for primary aldosteronism, renal artery stenosis, obstructive sleep apnea, or interfering medications (especially NSAIDs). 1