Pharmacological Treatment of Arterial Hypertension

Article written and reviewed by Dr Luca Moretti

If blood pressure remains elevated after 3–6 months of lifestyle modifications, or if the patient is at moderate or high risk, pharmacological therapy becomes necessary.

The main drug classes used for blood pressure control are:

• ACE inhibitors (e.g., enalapril, lisinopril, ramipril) → Block the angiotensin-converting enzyme (ACE), reducing the production of angiotensin II (a vasoconstrictor) and aldosterone release, resulting in antihypertensive and nephroprotective effects.
• ARBs (Angiotensin II Receptor Blockers) (e.g., losartan, valsartan, telmisartan) → Block the angiotensin II type 1 receptor (AT1) directly, preventing vasoconstriction and fluid retention without increasing bradykinin, thus reducing the risk of cough compared to ACE inhibitors.
• Dihydropyridine calcium channel blockers (e.g., amlodipine, nifedipine, felodipine) → Inhibit calcium influx into blood vessels, causing vasodilation and reduced peripheral resistance.
• Thiazide diuretics (e.g., hydrochlorothiazide, chlorthalidone, indapamide) → Inhibit sodium and chloride reabsorption in the distal tubule, reducing plasma volume and arterial stiffness, with a long-term antihypertensive effect.
• Beta-blockers (e.g., bisoprolol, metoprolol, carvedilol, nebivolol) → Block β-adrenergic receptors, reducing heart rate, cardiac output, and renin activity; indicated in patients with ischemic heart disease or heart failure.
• Loop diuretics (e.g., furosemide, torasemide, bumetanide) → Inhibit the Na-K-2Cl cotransporter in the loop of Henle, reducing extracellular volume; indicated in renal failure or heart failure.
• Aldosterone antagonists (e.g., spironolactone, eplerenone) → Antagonize aldosterone in the renal tubules, increasing sodium and water excretion and reducing resistant hypertension.
• Non-dihydropyridine calcium channel blockers (e.g., verapamil, diltiazem) → Act on calcium channels in the heart and vessels, reducing heart rate and contractility; used in patients with tachyarrhythmias or angina.
• Alpha-blockers (e.g., doxazosin, prazosin, terazosin) → Block α1-adrenergic receptors, causing vasodilation; indicated in patients with benign prostatic hyperplasia and hypertension.
• Potassium-sparing diuretics (e.g., amiloride, triamterene) → Inhibit sodium channels in the distal tubule, reducing potassium loss; often used in combination with other diuretics.
• Central sympatholytics (e.g., clonidine, methyldopa, moxonidine) → Stimulate central α2 receptors, reducing sympathetic tone and lowering blood pressure; indicated in resistant hypertension and in pregnancy (methyldopa).
• Direct vasodilators (e.g., hydralazine, minoxidil) → Relax arterial smooth muscle, reducing peripheral resistance; used in severe or refractory hypertension.
• Direct renin inhibitors (e.g., aliskiren) → Directly inhibit renin, preventing the formation of angiotensin I and II; indicated in selected cases.
• Phentolamine → Non-selective α-adrenergic blocker, used for hypertensive crises due to pheochromocytoma.

🚨 Fundamental rule: never combine an ACE inhibitor and an ARB due to the risk of renal failure and hyperkalemia.

Therapeutic Choice Based on Risk

The ACD scheme guides antihypertensive therapy in a practical way:

• ✅ A → ACE inhibitors or ARBs → First choice in younger patients (< 55 years) or with renal diseases.
• ✅ C → Calcium channel blockers → Indicated in patients over 55, in those of African descent, and in cases of angina.
• ✅ D → Thiazide diuretics → Preferred in the elderly and those with isolated systolic hypertension.

Start with monotherapy, then move to dual therapy (A + C or A + D). If blood pressure control is insufficient, add a third drug (A + C + D). If hypertension persists, add spironolactone or beta-blockers in selected cases.

Specifically, hypertension therapy is not based solely on blood pressure values, but on the stratification of Cardiovascular Risk.

Low Cardiovascular Risk Patients

Lifestyle modifications for 3–6 months as the first therapeutic strategy.
If blood pressure values remain elevated after this period, proceed with monotherapy, choosing among ACE inhibitors, ARBs, calcium channel blockers, or thiazide diuretics, based on patient characteristics.
If blood pressure is not adequately controlled within 1–3 months, increase the dosage of the initial drug up to the maximum tolerated dose.
In case of insufficient response, switch drug (e.g., replace an ACE inhibitor with an ARB or a calcium channel blocker with a diuretic).
If blood pressure remains elevated, move to dual therapy.

Moderate-Risk Patients

Immediate initiation of pharmacological therapy, without waiting for failure of lifestyle modifications.
Preferably use a dual therapy in a single-pill combination, generally with an ACE inhibitor or ARB + calcium channel blocker or thiazide diuretic.
Monitor after 1 month with possible adjustments. If blood pressure values are not at target, increase the dosage of the dual therapy up to the maximum tolerated dose.
If blood pressure control is still insufficient, consider switching one component of the combination (e.g., replace the calcium channel blocker with a diuretic).
If blood pressure remains high, move to triple therapy.

High Cardiovascular Risk Patients

Dual therapy combined from the start, preferably in single-pill formulations.
The recommended combination is ACE inhibitor or ARB + calcium channel blocker or thiazide diuretic.
After 1 month, if blood pressure is not controlled, increase the dosage of the dual therapy up to the maximum tolerated dose.
If blood pressure remains elevated, you can replace one of the two drugs with another of the same class.
If, after 3 months, blood pressure control is still inadequate, move to triple therapy, adding the missing drug between thiazide diuretic and calcium channel blocker.
If blood pressure remains high, consider adding spironolactone or other second-line drugs (quadruple therapy).
Strict monitoring is essential to prevent the risk of organ damage.

Very High-Risk Patients

Immediate intensive therapy with a triple single-pill combination: ACE inhibitor or ARB + calcium channel blocker + thiazide diuretic.
In the presence of heart failure or renal insufficiency, consider using a loop diuretic instead of a thiazide.
Monitor after 1 month and, if blood pressure targets are not achieved, increase the dosage of the triple therapy.
If blood pressure control is still unsatisfactory, consider switching one drug before introducing a fourth.
If blood pressure remains high, add a fourth drug, usually spironolactone, or a beta-blocker if indicated (e.g., in ischemic heart disease or atrial fibrillation).
In cases of resistant hypertension, renal denervation may be considered, a minimally invasive procedure that uses radiofrequency or ultrasound to ablate the peri-renal sympathetic nerve fibers.

Conclusion

Arterial hypertension is a complex condition that requires a personalized approach.
Optimal management is based on a combination of lifestyle modifications and pharmacological therapy, with risk stratification to tailor treatment to patient characteristics.

The key strategies include:

• ✅ Precise blood pressure targets, differentiated by patient category.
• ✅ Early use of drug combinations to improve blood pressure control.
• ✅ Regular monitoring to adapt therapy and prevent complications.

An integrated and timely approach is essential to reduce mortality and improve the quality of life in patients with arterial hypertension.
It is of fundamental importance to always combine pharmacological treatment with Non-Pharmacological Therapy, focused on lifestyle and modifiable risk factors.

References
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