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Introduction
Hypertension (HTN) remains a leading cause of cardiovascular morbidity and mortality worldwide. In resource-limited settings such as small community hospitals, the selection of antihypertensive drugs should balance efficacy, safety, affordability, and availability. This article outlines evidence-based and practical guidelines to optimize antihypertensive therapy in such contexts.
Key Concepts in Antihypertensive Drug Selection
Prioritize Evidence-Based Drug Groups: Drugs with robust evidence for reducing cardiovascular outcomes include:
ACE inhibitors (ACEi)
Angiotensin receptor blockers (ARBs)
Calcium channel blockers (CCBs)
Thiazide diuretics
Beta-blockers (in specific conditions)
Individualize Treatment Based on Comorbidities: Consider co-existing diseases (e.g., CKD, diabetes, or heart failure) to select the most suitable drug class.
Avoid Harmful Combinations:
ACEi and ARBs: Avoid simultaneous use due to the risk of acute kidney injury (AKI) and hyperkalemia.
Monitor Regularly for Safety and Efficacy: Baseline and follow-up laboratory tests (e.g., renal function, electrolytes) are crucial to minimize adverse effects.
Available Drug Groups in Small Community Hospitals
1. ACE Inhibitors (ACEi)
Example: Enalapril (5 mg, 20 mg tablets)
Maximum Dose: 40 mg/day
Key Features:
First-line therapy for HTN in CKD, heart failure (HFrEF), or proteinuria.
Adjust Dose for Renal Function:
CrCL 10-30 mL/min: Start with 2.5 mg/day.
CrCL <10 mL/min: Not recommended; if necessary, maximum 10 mg/day.
Common Side Effects: Dry cough (not dose-dependent), hyperkalemia.
Contraindications: History of angioedema, pregnancy, bilateral renal artery stenosis.
Monitoring:
Baseline and 2-4 week Cr, K+.
Discontinue if K+ > 5.5 mEq/L or eGFR decreases >25%.
2. Angiotensin Receptor Blockers (ARBs)
Example: Losartan (50 mg tablets)
Maximum Dose: 100 mg/day
Preferred Use:
Alternative to ACEi when cough is intolerable.
Added benefit in atrial fibrillation (AF) for reducing recurrence.
No dose adjustment needed for renal impairment.
3. Calcium Channel Blockers (CCBs)
Example: Amlodipine (5 mg tablets)
Maximum Dose: 10 mg/day
Indications:
Effective in isolated systolic HTN and HFrEF.
No renal adjustment required.
Common Side Effects: Peripheral edema, flushing.
4. Thiazide Diuretics
Example: Hydrochlorothiazide (HCTZ) (25 mg tablets)
Maximum Dose: 50-200 mg/day (dose-dependent)
Precautions:
Avoid in poorly controlled diabetes, gout, or dyslipidemia.
Electrolyte Monitoring: Risk of hypoK+, hypoNa+, hyperuricemia, hyperglycemia.
Adjust dose for CrCL <10 mL/min: Not recommended.
5. Beta-Blockers
Example: Atenolol (50 mg tablets)
Maximum Dose: 100 mg/day
Use Cases:
Post-myocardial infarction, AF rate control, or HFrEF.
Contraindications:
Avoid in severe asthma/COPD and decompensated heart failure.
Renal Adjustment:
CrCL 10-30 mL/min: Max 50 mg/day.
CrCL <10 mL/min: Max 25 mg/day.
6. Potassium-Sparing Diuretics
Example: Spironolactone (25 mg tablets)
Maximum Dose: 50-200 mg/day
Specific Use:
Resistant HTN, aldosterone antagonism in heart failure.
Renal Adjustment:
GFR <30 mL/min: Not recommended.
Monitoring: Hyperkalemia, gynecomastia.
7. Alpha-Blockers
Example: Doxazosin (2 mg tablets)
Maximum Dose: 8-16 mg/day
Key Notes:
Useful in coexisting benign prostatic hyperplasia (BPH).
Avoid in HFrEF.
Common Side Effect: Orthostatic hypotension.
8. Direct Vasodilators
Example: Hydralazine (25 mg tablets)
Maximum Dose: 300 mg/day
Indications:
Adjunct therapy in resistant HTN or heart failure (with nitrates).
Monitoring: Risk of lupus-like syndrome.
Practical Considerations
Patient Evaluation
Baseline Testing:
Renal function, electrolytes, and EKG.
Regular Monitoring:
Serum potassium and creatinine (especially with ACEi/ARB, diuretics).
Summary Table
Drug Class | Example | Max Dose | Key Monitoring | Special Considerations |
ACEi | Enalapril | 40 mg/day | Cr, K+ | Avoid in pregnancy, bilateral RAS |
ARBs | Losartan | 100 mg/day | K+ | No renal adjustment required |
CCB | Amlodipine | 10 mg/day | Edema | Safe in CKD |
Thiazides | HCTZ | 50-200 mg/day | Electrolytes, Uric acid | Avoid in gout, DM |
Beta-Blockers | Atenolol | 100 mg/day | HR, BP | Selective agents for asthma |
Potassium-Sparing | Spironolactone | 50-200 mg/day | K+, gynecomastia | Avoid if GFR <30 mL/min |
Alpha-Blockers | Doxazosin | 8-16 mg/day | BP (orthostatic) | Useful in BPH |
Direct Vasodilators | Hydralazine | 300 mg/day | Lupus-like syndrome | Used in combination therapy |
References
2019 Thai Guidelines on Hypertension Treatment
KDIGO 2021 Clinical Practice Guidelines for Blood Pressure in CKD
ESC/ESH 2018 Guidelines on Hypertension
JNC 8 Guidelines for Hypertension Management
UpToDate® and ACC/AHA Hypertension Guidelines.
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