Hypertension is a leading cause of cardiovascular disease and mortality worldwide. Effective management with antihypertensive medications reduces the risk of complications such as stroke, myocardial infarction, and chronic kidney disease. Prescribing the right antihypertensive requires an individualized approach based on patient characteristics, comorbidities, and drug-specific factors.
1. Goals of Hypertension Management
- Primary Goals:
- Reduce blood pressure (BP) to target levels:
- <140/90 mmHg for most patients.
- <130/80 mmHg for high-risk patients (e.g., with diabetes, chronic kidney disease).
- Minimize the risk of cardiovascular and renal complications.
- Reduce blood pressure (BP) to target levels:
2. First-Line Antihypertensive Classes
a. Angiotensin-Converting Enzyme (ACE) Inhibitors
- Examples: Enalapril, Lisinopril, Ramipril.
- Mechanism: Inhibits the conversion of angiotensin I to angiotensin II, reducing vasoconstriction and aldosterone secretion.
- Indications:
- First-line for hypertension in younger patients (<55 years).
- Beneficial in:
- Heart failure.
- Post-myocardial infarction.
- Diabetic nephropathy.
- Side Effects:
- Cough (due to bradykinin accumulation).
- Hyperkalemia.
- Angioedema (rare but serious).
- Contraindications:
- Pregnancy.
- Bilateral renal artery stenosis.
b. Angiotensin II Receptor Blockers (ARBs)
- Examples: Losartan, Valsartan, Telmisartan.
- Mechanism: Block angiotensin II receptors, reducing vasoconstriction.
- Indications:
- Alternative for patients intolerant to ACE inhibitors.
- Similar benefits in heart failure, diabetes, and chronic kidney disease.
- Side Effects:
- Hyperkalemia.
- Dizziness.
- Contraindications:
- Same as ACE inhibitors.
c. Calcium Channel Blockers (CCBs)
- Examples:
- Dihydropyridines: Amlodipine, Nifedipine (vascular selective).
- Non-dihydropyridines: Verapamil, Diltiazem (cardioselective).
- Mechanism: Block calcium entry into smooth muscle cells, causing vasodilation and reducing cardiac workload.
- Indications:
- First-line for patients >55 years or of African/Caribbean origin.
- Effective in isolated systolic hypertension.
- Side Effects:
- Peripheral edema.
- Flushing.
- Constipation (more common with verapamil).
- Contraindications:
- Severe heart failure (non-dihydropyridines).
d. Thiazide Diuretics
- Examples: Hydrochlorothiazide, Chlorthalidone, Indapamide.
- Mechanism: Increase sodium and water excretion, reducing plasma volume.
- Indications:
- Effective in elderly patients.
- Ideal for patients with osteoporosis (reduce calcium excretion).
- Side Effects:
- Hypokalemia, hyponatremia.
- Hyperuricemia (risk of gout).
- Hyperglycemia.
- Contraindications:
- Severe renal impairment.
3. Second-Line and Add-On Therapies
a. Beta Blockers
- Examples: Metoprolol, Bisoprolol, Atenolol.
- Mechanism: Block beta-adrenergic receptors, reducing heart rate and cardiac output.
- Indications:
- Post-myocardial infarction.
- Angina.
- Heart failure with reduced ejection fraction.
- Side Effects:
- Bradycardia, fatigue, sexual dysfunction.
- Contraindications:
- Asthma, severe bradycardia.
b. Aldosterone Antagonists
- Examples: Spironolactone, Eplerenone.
- Mechanism: Block aldosterone receptors, promoting sodium excretion.
- Indications:
- Resistant hypertension.
- Heart failure with reduced ejection fraction.
- Side Effects:
- Hyperkalemia.
- Gynecomastia (spironolactone).
- Contraindications:
- Hyperkalemia, severe renal impairment.
c. Alpha Blockers
- Examples: Doxazosin, Prazosin.
- Mechanism: Block alpha-adrenergic receptors, causing vasodilation.
- Indications:
- Hypertension with benign prostatic hyperplasia (BPH).
- Side Effects:
- Postural hypotension.
- Dizziness.
- Contraindications:
- Orthostatic hypotension.
d. Direct Renin Inhibitors
- Example: Aliskiren.
- Mechanism: Inhibits renin, reducing angiotensin II formation.
- Indications:
- Limited role in routine practice; adjunct in resistant hypertension.
- Side Effects:
- Hyperkalemia, diarrhea.
- Contraindications:
- Combination with ACE inhibitors or ARBs in diabetic patients.
4. Hypertension in Special Populations
a. Diabetes:
- ACE inhibitors or ARBs are preferred to protect against nephropathy.
b. Chronic Kidney Disease (CKD):
- ACE inhibitors or ARBs slow progression of renal disease.
c. Heart Failure:
- ACE inhibitors, ARBs, beta blockers, and aldosterone antagonists are essential.
d. Pregnancy:
- Safe options: Methyldopa, Labetalol, Nifedipine.
- Avoid: ACE inhibitors, ARBs, direct renin inhibitors.
e. Elderly Patients:
- Start with lower doses due to increased risk of postural hypotension.
- Prefer thiazide diuretics or CCBs.
5. Monitoring and Follow-Up
- Blood Pressure Targets:
- Check BP regularly to ensure targets are met.
- Electrolytes and Renal Function:
- Monitor serum potassium and creatinine for patients on ACE inhibitors, ARBs, or diuretics.
- Adherence:
- Reinforce medication adherence and lifestyle modifications.
6. Patient Counselling Points
- Medication Adherence:
- Take medications as prescribed, even if BP improves.
- Lifestyle Changes:
- Reduce salt intake, maintain a healthy weight, exercise regularly, and avoid smoking and excessive alcohol.
- Side Effects:
- Report any persistent side effects such as dizziness, swelling, or unusual fatigue.
- Regular Monitoring:
- Attend follow-up visits for BP checks and lab tests.
7. Summary Table
| Drug Class | First-Line Use | Advantages | Side Effects | Special Considerations |
|---|---|---|---|---|
| ACE Inhibitors | Younger patients, CKD | Renal protection | Cough, hyperkalemia | Avoid in pregnancy |
| ARBs | ACE-intolerant patients | Fewer side effects | Hyperkalemia, dizziness | Preferred alternative to ACE |
| CCBs | Older, Black patients | Effective in elderly | Edema, flushing | Avoid non-dihydropyridines in HF |
| Thiazides | Elderly, osteoporosis | Inexpensive, effective | Hypokalemia, hyperglycemia | Caution in gout |
| Beta Blockers | Post-MI, heart failure | Cardioprotective | Bradycardia, fatigue | Avoid in asthma |
Conclusion
Prescribing antihypertensives requires a patient-centered approach that considers age, comorbidities, and potential side effects. By tailoring treatment and emphasizing adherence to lifestyle modifications, healthcare professionals can achieve effective blood pressure control and reduce the risk of hypertension-related complications. Regular follow-ups and patient education are critical to ensuring long-term success.
