Management of Uncontrolled Hypertension on Irbesartan Monotherapy
Add amlodipine 5 mg once daily to the current Irbesartan 150 mg regimen, as combination therapy with a calcium channel blocker provides superior blood pressure control and is the guideline-recommended approach for uncontrolled hypertension on ARB monotherapy. 1
Rationale for Adding Amlodipine
The 2024 ESC Guidelines and 2020 ISH Guidelines both recommend that when BP remains uncontrolled on a single agent, the preferred combination is a RAS blocker (ARB or ACE inhibitor) with a dihydropyridine calcium channel blocker or thiazide diuretic 1
The patient's BP of 160-170/110 mmHg on Irbesartan 150 mg alone represents uncontrolled hypertension requiring escalation to combination therapy 1
Adding amlodipine to irbesartan produces additive antihypertensive effects with excellent tolerability, achieving mean reductions of 21.5 mmHg systolic when combined versus only 8.6 mmHg with ARB monotherapy 2
Dosing and Dispensing (PhilHealth Formulary Compliant)
Medication Regimen:
- Irbesartan 150 mg - Continue 1 tablet once daily in the evening (current regimen)
- Amlodipine 5 mg - Add 1 tablet once daily in the morning
- Dispense: 30 tablets of amlodipine 5 mg for 30 days
Alternative if Amlodipine Not Available or Not Tolerated
Add hydrochlorothiazide 12.5-25 mg once daily as the combination of irbesartan with thiazide diuretics produces additive BP reduction with excellent tolerability 1, 3
The fixed-dose combination of irbesartan/hydrochlorothiazide shows dose-dependent antihypertensive effects up to HCTZ 25 mg with high tolerability 3
Next Steps if BP Remains Uncontrolled
If BP remains ≥140/90 mmHg after 3 months on dual therapy, escalate to triple therapy by adding a thiazide/thiazide-like diuretic (if using irbesartan + amlodipine) or adding amlodipine (if using irbesartan + HCTZ) 1
If BP remains uncontrolled on triple therapy (ARB + CCB + thiazide), add spironolactone 12.5-25 mg daily, which provides an average additional reduction of 25/12 mmHg in resistant hypertension 1, 4
Critical Monitoring
Recheck BP in 2-4 weeks to assess response, with target BP <140/90 mmHg (or <130/80 mmHg given cardiovascular risk) 1
Monitor serum creatinine and potassium if diuretics or spironolactone are added, especially in combination with ARB therapy 4
Confirm medication adherence and consider home BP monitoring to exclude white coat hypertension 1
Important Caveats
Avoid NSAIDs as they interfere with BP control and should be withdrawn or used at the lowest effective dose 1
Do not combine Irbesartan with an ACE inhibitor, as dual RAS blockade increases hyperkalemia and renal dysfunction risk without additional BP benefit 1, 4
The combination of amlodipine with irbesartan has placebo-like tolerability with no significant increase in adverse events compared to monotherapy 2
PhilHealth Medical Assessment
Diagnosis: Uncontrolled Essential Hypertension (Stage 2)
Medical Assessment: 57-year-old male with hypertension for 1 year, currently on Irbesartan 150 mg once daily with persistent BP elevation (160-170/110 mmHg). Normal cholesterol and creatinine. Requires escalation to combination therapy per guidelines.
Plan/Recommendation:
- Continue Irbesartan 150 mg 1 tablet once daily in the evening
- Add Amlodipine 5 mg 1 tablet once daily in the morning
- Dispense: Amlodipine 5 mg #30 tablets for 30 days
- Lifestyle modifications: salt restriction, regular exercise, weight management
- Follow-up in 4 weeks for BP recheck
- Target BP <140/90 mmHg
Estimated Cost: Amlodipine 5 mg (generic) approximately ₱3-5 per tablet = ₱90-150 for 30 days (well within ₱300 budget)
Medical Certificate
This certifies that the patient has been seen and examined today with the diagnosis of: Uncontrolled Essential Hypertension (Stage 2)
Recommendation: Medication adjustment with addition of calcium channel blocker. Patient is fit to return to work with continued medical management and follow-up.
This medical certificate is issued upon the request of the patient for: return to work, having taken leave due to medical consultation for blood pressure management.