Pharmacological Management of Hypertension at the PHC Level

1. When to Initiate Drug Therapy

• Patients <80 years: target <140/90 mmHg
• Patients ≥80 years: target <150/90 mmHg
• With DM or CKD/proteinuria: target <130/80 mmHg

2. The A-C-D Framework (First-Line Drugs)

• A = ACE inhibitors (e.g., enalapril 5-40 mg/day) OR ARBs (e.g., losartan 25-100 mg/day) if ACE inhibitor intolerance
• C = Calcium Channel Blockers (e.g., amlodipine 2.5-10 mg/day)
• D = Thiazide/thiazide-like Diuretics (e.g., hydrochlorothiazide 12.5-25 mg/day; chlorthalidone preferred for longer duration)

3. Step-by-Step Treatment Algorithm

Step 1 - Monotherapy

• Start with one first-line drug (C, A, or D)
• Assess at 4-6 weeks; titrate to optimal dose
• If target not achieved, add a second agent

Step 2 - Dual Therapy

• A + C (ACE/ARB + CCB) - preferred; CCB edema reduced by ACE inhibitor
• A + D (ACE/ARB + diuretic) - reduces ACE inhibitor-associated hypokalemia
• C + D (CCB + diuretic) - useful when RAS inhibitors not tolerated

Step 3 - Triple Therapy

• A + C + D - the evidence-based "Gold Standard" triple combination
• Adds a beta-blocker if heart failure or post-MI

Step 4 - Resistant Hypertension

• Add spironolactone 25-50 mg/day (if eGFR adequate, K+ normal)
• Or add alpha-blocker, beta-blocker, or central sympatholytic
• Refer to higher centre for further evaluation

4. Drug Class Profiles for PHC Use

A. Calcium Channel Blockers (CCBs) - Prototype: Amlodipine

• Mechanism: Inhibit voltage-gated Ca²⁺ channels → arterial vasodilation
• Dose: 2.5-10 mg once daily
• Advantages: Effective in all ethnic groups (including Black patients), most effective for stroke prevention, BP reduction independent of dietary sodium and NSAID use
• Side effects: Peripheral edema (dose-dependent, worse in women), gingival hyperplasia; avoid short-acting nifedipine chronically
• Goldman-Cecil Medicine, p. 754

B. ACE Inhibitors - Prototype: Enalapril

• Mechanism: Block conversion of Ang I → Ang II; inhibit bradykinin degradation
• Dose: Enalapril 5-40 mg/day (once or twice daily)
• Advantages: Cardioprotective, nephroprotective (especially in diabetic nephropathy), reduce intraglomerular pressure; also reduce CCB-related edema
• Side effects: Dry cough (10-20%), angioedema (rare, contraindicated in pregnancy), hyperkalemia; minor GFR rise (<30% of baseline) is acceptable
• Caution: Can precipitate AKI in bilateral renal artery stenosis

C. ARBs - Prototype: Losartan, Telmisartan

• Use: When ACE inhibitor not tolerated (cough, angioedema)
• Mechanism: Block AT1 receptor; less bradykinin accumulation than ACEi
• Dose: Losartan 25-100 mg/day; Telmisartan 20-80 mg/day
• Same renal and cardiac benefits as ACEi

D. Thiazide Diuretics - Prototype: HCTZ, Chlorthalidone

• Mechanism: Inhibit Na⁺/Cl⁻ cotransporter in distal convoluted tubule
• Dose: HCTZ 12.5-25 mg/day; Chlorthalidone 12.5-25 mg/day (preferred - longer 48-72 hour action vs 16-24h for HCTZ; better mean 24h BP control)
• Advantages: Proven reduction in CV morbidity/mortality including stroke, HF; effective in elderly; equally effective as CCBs and ACEi in ALLHAT trial
• Side effects: Hypokalemia, hyponatremia, hyperuricemia, impaired glucose tolerance, dyslipidemia, photosensitivity
• National Kidney Foundation Primer, p. 691

E. Beta-Blockers - Prototype: Atenolol, Metoprolol

• Not first-line for uncomplicated hypertension
• Compelling indications: Post-MI, angina, heart failure with reduced EF, rate control in AF, thyrotoxicosis, pregnancy
• Dose: Atenolol 25-100 mg/day; Metoprolol succinate 25-200 mg/day

5. Compelling Indications - Drug Choice by Comorbidity

6. Special Situations at PHC Level

Hypertensive Urgency (SBP ≥180/DBP ≥110, no acute TOD)

• Oral amlodipine 5-10 mg or short-acting nifedipine 10 mg sublingually
• Oral captopril 12.5-25 mg (rapid onset)
• Oral clonidine 0.2 mg (with caution - risk of rebound)
• Aim to lower BP gradually over 24-48 hours (not rapidly)
• Review at PHC; refer if no response

Hypertensive Emergency (with acute TOD - encephalopathy, stroke, ACS, acute HF)

• Refer immediately to hospital
• Initiate IV antihypertensives before transfer (IV labetalol, IV hydralazine if available)

7. Follow-up and Monitoring Protocol at PHC

• Newly initiated / drug changed: Review at 2-4 weeks
• BP controlled on stable therapy: Every 3-6 months
• Monitor at each visit: BP (both arms, seated + standing in elderly), weight, pulse, symptoms of side effects
• Laboratory monitoring: Serum creatinine, electrolytes (especially K⁺ when using ACEi/ARB or diuretics), urine for proteinuria, fasting blood sugar, lipid profile (annually)
• Hypertension registry at PHC level for patient tracking and improving adherence
• Team approach: Physician, nurses, ASHA workers, pharmacist - for counseling and community follow-up

8. Non-Pharmacological Measures (Adjunct to All Steps)

Key Points for PHC Practice

1. Prefer once-daily drugs (amlodipine, chlorthalidone, losartan, enalapril once daily) for better adherence
2. Fixed-dose combinations (FDCs) improve adherence - e.g., amlodipine + enalapril, amlodipine + losartan + HCTZ
3. Never use dual RAS blockade (ACEi + ARB simultaneously) in routine practice
4. Never abruptly stop beta-blockers or clonidine (rebound hypertension)
5. ACEi/ARBs are contraindicated in pregnancy - switch to methyldopa or nifedipine
6. Re-evaluate any patient with sudden poor BP control for secondary hypertension (renal artery stenosis, primary aldosteronism, pheochromocytoma) and refer
7. Criteria for referral from PHC: Grade 3 HTN unresponsive, hypertensive emergency, suspected secondary HTN, pregnancy with HTN, resistant HTN

Hypertension - As per Park's Textbook of Preventive and Social Medicine (PSM)

1. Introduction and Public Health Significance

• Global prevalence of hypertension: 1.13 billion (2015 estimate)
• Overall adult prevalence: 30-40% worldwide
• Elevated BP accounts for almost 10 million deaths and over 200 million DALYs in 2015
• Projected to increase by 15-20% by 2025

2. "Rule of Halves" (Iceberg Concept)

• Only half of hypertensives are aware of their condition
• Only half of those aware are on treatment
• Only half of those on treatment are adequately controlled

3. Definition and Classification

TABLE 1 - Classification of Blood Pressure (Park's PSM)

• When systolic and diastolic fall in different categories, the higher category is used
• Classification applies only to adults not taking antihypertensive drugs and not acutely ill

4. Classification by Type

• Primary (Essential) Hypertension: Causes generally unknown; accounts for 90% of all hypertension cases
• Secondary Hypertension: ~10% of cases; caused by renal diseases (chronic glomerulonephritis, chronic pyelonephritis), adrenal tumours (pheochromocytoma, Conn's), coarctation of aorta, toxaemia of pregnancy, oral contraceptives

5. Risk Factors for Hypertension

A. Non-Modifiable Risk Factors

B. Modifiable Risk Factors

6. "Tracking" of Blood Pressure

7. Target Organ Damage (TOD)

8. Blood Pressure Measurement (Park's Emphasis)

• (a) Observer errors: Hearing acuity, interpretation of Korotkoff sounds
• (b) Instrumental errors: Leaking valve, cuffs not encircling the arm (too-small cuff = falsely high reading)
• (c) Subject errors: Physical environment, position of subject, fear/anxiety

• Sitting position preferred over supine
• Consistent use of right or left arm in any clinic
• Phase I = Systolic; Phase V (disappearance of sounds) = Diastolic
• Measure at least 3 times over 3 minutes; record the lowest reading
• Diagnosis on average of 2 or more readings on 2 or more occasions

9. Prevention of Hypertension (Park's Framework)

Prevention of Hypertension
├── 1. Primary Prevention
│   ├── (a) Population Strategy
│   └── (b) High-Risk Strategy
└── 2. Secondary Prevention

A. Primary Prevention

(a) Population Strategy (Rose's Strategy)

• (a) Nutrition: Reduce salt to ≤5 g/day; moderate fat; avoid high alcohol; restrict calorie intake
• (b) Weight reduction: Correct overweight/obesity (BMI >25)
• (c) Exercise promotion: Regular physical activity reduces weight, blood lipids, and BP
• (d) Behavioural changes: Reduce stress, stop smoking, yoga, transcendental meditation
• (e) Health education: Mobilize community; preventive advice on all risk factors
• (f) Self-care: Teach patient to take own BP and maintain log-book; reduces burden on health services

(b) High-Risk Strategy

B. Secondary Prevention - Treatment of Established Hypertension

(i) Early Case Detection

• High BP rarely causes symptoms until organ damage has occurred
• Only effective method of diagnosis: screen the population
• Screening not linked to follow-up and treatment is a "fruitless exercise"
• Do not initiate screening if health resources for treatment and follow-up are not adequate

(ii) Treatment Goals (Park's PSM)

• Aim: BP below 140/90 mmHg
• Ideal target: 120/80 mmHg
• Treatment reduces incidence of stroke, heart failure, renal failure, and myocardial infarction
• Care must also address other risk factors: smoking, elevated cholesterol

10. Lifestyle Modifications (TABLE 2 - Park's PSM)

• Effects are dose- and time-dependent and could be higher for some individuals

11. Pharmacological Management (Drug Therapy at PHC Level - Park's PSM)

First-Line Drug Classes (A-C-D Framework as referenced in Park's via MoHFW guidelines):

• A = ACE Inhibitors (e.g., Enalapril) OR ARBs (e.g., Losartan) if ACE inhibitor intolerant
• C = Calcium Channel Blockers (e.g., Amlodipine)
• D = Thiazide/Thiazide-like Diuretics (e.g., Hydrochlorothiazide, Chlorthalidone)
• B = Beta-blockers (e.g., Atenolol) - for compelling indications

Step-wise Treatment Algorithm

Grade-Based Initiation (Park's/MoHFW STG):

Patient Compliance - Park's Emphasis

12. Hypertension Control Programme (Community/PHC Level)

• Control of hypertension at community level is feasible
• It can be carried out through the existing system of health services
• BP control leads to reduction in: stroke, heart failure, renal failure, and myocardial infarction
• Some countries have launched nationwide control programmes based on these findings

1. Screening - population-based BP measurement at every health contact
2. Diagnosis and classification - using validated, calibrated devices
3. Lifestyle modification - non-pharmacological interventions for all
4. Pharmacological treatment - stepped care with first-line drugs
5. Hypertension Registry at PHC/CHC level for patient tracking
6. Team approach - physicians, nurses, ASHA workers, community health workers
7. Follow-up and adherence - regular monitoring every 3-6 months
8. Health education - patient and community education

13. Hypertension as a Risk Factor for Other Diseases (Park's Context)