What are the guidelines for managing hypertension in a patient in the Philippines?

Hypertension Management Guidelines in the Philippines

Blood Pressure Definition and Diagnosis

The Philippine Society of Hypertension defines hypertension as an office blood pressure of ≥140/90 mmHg following proper standard BP measurement technique. 1, 2, 3

• Confirm elevated readings with at least two additional measurements using a validated device with appropriate cuff size 4
• Home BP monitoring (≥135/85 mmHg) or 24-hour ambulatory monitoring (≥130/80 mmHg) can confirm sustained hypertension 4

Blood Pressure Targets

Target BP should be <140/90 mmHg for most adults, with <130/80 mmHg for higher-risk patients including those with diabetes, chronic kidney disease, or established cardiovascular disease. 1, 4

• Aim to achieve target BP within 3 months of initiating or modifying therapy 4
• Initial goal should be to reduce BP by at least 20/10 mmHg 4

Lifestyle Modifications

Sodium restriction to as low as 1500 mg/day is recommended, with the American Heart Association recommending limitation to 2300 mg/day in most healthy individuals and 1500 mg/day in people with prehypertension or hypertension. 1

• The DASH meal plan that is low in sodium and high in dietary potassium can be recommended for all patients with hypertension without renal insufficiency 1
• Potassium-rich diet from food sources (not supplements) may help reduce BP, but should be avoided in patients with chronic renal failure or taking potassium-sparing diuretics 1
• Weight management, regular aerobic exercise, and alcohol limitation provide additive BP reductions of 10-20 mmHg 4

Pharmacological Treatment Algorithm

Initial Therapy for Grade 2 Hypertension (≥160/100 mmHg)

Start immediate drug treatment for Grade 2 hypertension. 4

For Non-Black Patients:

• Start with low-dose ACE inhibitor or ARB (e.g., lisinopril) 4
• Alternative: Start with dihydropyridine calcium channel blocker (e.g., amlodipine) 5

For Black Patients:

• Start with low-dose ARB plus dihydropyridine CCB (e.g., amlodipine) OR dihydropyridine CCB plus thiazide-like diuretic 4

Dual Therapy (If BP Uncontrolled on Monotherapy)

For patients on ACE inhibitor/ARB monotherapy:

• Add calcium channel blocker (amlodipine 5-10 mg daily) as preferred second agent 4, 5
• Alternative: Add thiazide-like diuretic (chlorthalidone 12.5-25 mg or hydrochlorothiazide 25 mg daily) 4, 5

For patients on calcium channel blocker monotherapy:

• Add ACE inhibitor or ARB 5
• For Black patients specifically, adding a thiazide diuretic may be more effective than adding an ACE inhibitor/ARB 5

Triple Therapy (If BP Uncontrolled on Dual Therapy)

The guideline-recommended triple therapy combination is: RAS blocker (ACE inhibitor or ARB) + dihydropyridine calcium channel blocker + thiazide/thiazide-like diuretic. 1, 4, 5

• This combination targets three complementary mechanisms: renin-angiotensin system blockade, vasodilation, and volume reduction 5
• Chlorthalidone is preferred over hydrochlorothiazide due to its longer duration of action and superior cardiovascular outcomes 5
• Single-pill combinations are strongly preferred to improve medication adherence 5

Resistant Hypertension (Uncontrolled on Triple Therapy)

If BP remains ≥140/90 mmHg despite three medications at optimal doses including a diuretic:

1. First, verify medication adherence - non-adherence is the most common cause of apparent treatment resistance 1, 4, 5
2. Rule out interfering substances: NSAIDs, decongestants, oral contraceptives, systemic corticosteroids, excessive alcohol (>2 drinks/day for men), high sodium diet (>2 g/day) 5
3. Screen for secondary hypertension: primary aldosteronism, renal artery stenosis, obstructive sleep apnea, pheochromocytoma 1, 4, 5
4. Add spironolactone 25-50 mg daily as the preferred fourth-line agent, which provides additional BP reductions of 20-25/10-12 mmHg 4, 5

Monitoring and Follow-up

• Schedule follow-up within 2-4 weeks after initiating or adjusting therapy to assess response 4, 5
• Monitor serum potassium and creatinine 2-4 weeks after initiating diuretic therapy or RAS blockers 5
• Consider home BP monitoring to track progress and improve adherence 4
• Refer to a hypertension specialist if BP remains uncontrolled despite four medications at optimal doses 1, 4, 5

Special Considerations for the Philippines

Monotherapy has been the mode of treatment in more than 80% of Filipino patients, which explains the low BP control rates of only 20-27%. 3, 6

• Among older Filipinos (≥60 years), 69.1% have hypertension, but only 61.6% are aware of their condition and 51.5% are untreated 6
• Medication adherence is reported to be as low as 66% among Filipino hypertensive patients 7
• Key factors positively associated with adherence in Filipinos: good patient-provider relationship, accessibility of health services, use of specialty clinics, and health insurance 7
• Key factors negatively associated with adherence: younger age, single status, low educational attainment, unemployment, low health literacy, and inconsistent drug regimen schedules 7

Critical Pitfalls to Avoid

• Never combine an ACE inhibitor with an ARB - this increases adverse events (hyperkalemia, acute kidney injury) without additional cardiovascular benefit 1, 5
• Do not add a beta-blocker as second or third agent unless there are compelling indications (angina, post-MI, heart failure with reduced ejection fraction, or heart rate control needed) 4, 5
• Do not use non-dihydropyridine CCBs (diltiazem or verapamil) in patients with left ventricular dysfunction or heart failure 1, 5
• Do not delay treatment intensification - prompt action is required for stage 2 hypertension to reduce cardiovascular risk 4, 5
• Do not add a third drug class before maximizing doses of the current two-drug regimen 5