Blood Pressure Medicines — Medication Guide, Uses & Safety — Uses, Dosage & Side Effects | MyMedicPlus

Blood pressure medicines, or antihypertensives, are prescription drugs used to lower elevated blood pressure (hypertension — defined as a sustained blood pressure above 130/80 mmHg by most current guidelines) and reduce the long-term risk of heart attack, stroke, kidney disease, heart failure, and premature death. Hypertension is one of the leading preventable causes of death globally, affecting over 1.28 billion adults, and often produces no symptoms — earning the name 'the silent killer.' There are five major first-line drug classes: ACE inhibitors (e.g. lisinopril, ramipril, perindopril), angiotensin receptor blockers/ARBs (e.g. losartan, valsartan, irbesartan), calcium channel blockers/CCBs (e.g. amlodipine, felodipine), thiazide and thiazide-like diuretics (e.g. hydrochlorothiazide, indapamide, chlorthalidone), and beta-blockers (e.g. atenolol, bisoprolol, nebivolol). Most patients with established hypertension require a combination of two or more drugs from different classes to achieve adequate blood pressure control, and treatment is generally lifelong. Antihypertensives are prescribed by general practitioners, cardiologists, nephrologists, and internists.

Antihypertensives are prescribed for a range of cardiovascular and renal conditions in addition to primary hypertension. Primary indications include primary (essential) hypertension — the most common form — and secondary hypertension (due to an identifiable cause such as renal artery stenosis, primary aldosteronism, or pheochromocytoma). ACE inhibitors and ARBs are specifically preferred in patients with hypertension complicated by diabetes, chronic kidney disease (CKD), proteinuria, or heart failure, where they provide additional organ protection beyond blood pressure lowering. Beta-blockers are used for hypertension with concurrent coronary artery disease, heart failure, post-heart attack, or atrial fibrillation rate control. Calcium channel blockers are preferred in elderly patients and those of African descent. Thiazide diuretics are first-line when combined therapy is used. Alpha-blockers (doxazosin) are used when benign prostatic hyperplasia (BPH) coexists with hypertension. IV antihypertensives (labetalol, sodium nitroprusside, hydralazine) are used in hypertensive emergencies (hypertensive crisis with end-organ damage). Target blood pressure depends on age, comorbidities, and risk — generally under 130/80 mmHg for most adults.

Each antihypertensive drug class works through a distinct mechanism. ACE inhibitors (lisinopril, ramipril, perindopril) block angiotensin-converting enzyme, which normally converts angiotensin I to angiotensin II — a potent vasoconstrictor. By blocking this conversion, ACE inhibitors dilate blood vessels, reduce aldosterone secretion (decreasing fluid and sodium retention), and lower blood pressure. They also have renal-protective effects by reducing intraglomerular pressure. Angiotensin receptor blockers (ARBs — losartan, valsartan, irbesartan) block the AT1 receptor to which angiotensin II binds, achieving similar vasodilatory and protective effects to ACE inhibitors but without the ACE inhibitor-specific cough side effect (because they do not block bradykinin degradation). Calcium channel blockers (amlodipine, nifedipine, felodipine) block voltage-dependent L-type calcium channels in vascular smooth muscle cells, reducing calcium influx and therefore preventing smooth muscle contraction — resulting in arterial vasodilation and blood pressure reduction. Beta-blockers (atenolol, bisoprolol, metoprolol) competitively block catecholamine (adrenaline/noradrenaline) binding to beta-1 adrenergic receptors in the heart, reducing heart rate and cardiac output — lowering blood pressure. Thiazide diuretics (hydrochlorothiazide, indapamide) inhibit the sodium-chloride cotransporter in the renal distal tubule, increasing urinary sodium and water excretion — reducing blood volume and blood pressure.

Antihypertensive dosing is individualized based on blood pressure targets, age, comorbidities, and tolerability. Common examples with typical adult oral dose ranges: amlodipine (CCB) 5–10 mg once daily; lisinopril (ACE inhibitor) 5–40 mg once daily; ramipril (ACE inhibitor) 2.5–10 mg once daily; losartan (ARB) 50–100 mg once daily or in two divided doses; valsartan (ARB) 80–320 mg once daily; atenolol (beta-blocker) 25–100 mg once daily; bisoprolol (beta-blocker) 2.5–10 mg once daily; hydrochlorothiazide (thiazide diuretic) 12.5–25 mg once daily; indapamide (thiazide-like diuretic) 1.5–2.5 mg once daily. Most antihypertensives are taken once daily for convenience and adherence. Blood pressure should be monitored at home and in clinic regularly. Doses are typically titrated slowly upward every 4–6 weeks based on blood pressure response. For resistant hypertension (BP uncontrolled on 3 full-dose drugs including a diuretic), specialist assessment is required. Never abruptly stop blood pressure medicines — always follow medical guidance.

Side effects differ significantly between antihypertensive drug classes, allowing prescribers to tailor therapy to individual patients. ACE inhibitors cause a persistent dry cough (from bradykinin accumulation) in 10–20% of patients — this is the most common reason for switching to an ARB. ACE inhibitors also commonly cause dizziness from postural hypotension (especially the first dose), raised blood potassium (hyperkalemia — particularly in combination with potassium-sparing diuretics or in kidney disease), and rare but potentially life-threatening angioedema (swelling of the throat and tongue — require emergency treatment). ARBs are generally better tolerated than ACE inhibitors with a similar efficacy profile. Calcium channel blockers (especially dihydropyridines like amlodipine) frequently cause peripheral ankle edema (in approximately 10–15% of patients — dose-dependent), facial flushing, and headache. Diltiazem and verapamil (non-dihydropyridine CCBs) can cause bradycardia and constipation. Beta-blockers cause fatigue and exercise intolerance (reduced maximum heart rate response), cold extremities, worsening of peripheral vascular disease, erectile dysfunction (in men), and can precipitate or worsen bronchospasm in asthmatics — use with great caution or avoid in asthma/reactive airway disease. Beta-blockers also mask the symptoms of hypoglycemia (sweating, tachycardia) in diabetic patients on insulin. Thiazide diuretics frequently cause low blood potassium (hypokalemia — risk of cardiac arrhythmias), increased urination, elevated uric acid (precipitating gout), and mild adverse effects on glucose and lipid metabolism. All antihypertensives can cause excessive blood pressure lowering (hypotension) — particularly the first dose of ACE inhibitors in volume-depleted patients.

Never stop blood pressure medication abruptly without medical guidance — this can cause rapid rebound hypertension and significantly increase the short-term risk of stroke, heart attack, and hypertensive emergency. ACE inhibitors and ARBs are absolutely contraindicated in pregnancy (FDA Pregnancy Category D/X) due to serious fetal and neonatal harm — discontinue immediately if pregnancy is confirmed and switch to a safe alternative (methyldopa, labetalol, or nifedipine). ACE inhibitors and ARBs must never be used together (dual renin-angiotensin-aldosterone system blockade) due to markedly increased risk of severe hypotension, hyperkalemia, and acute kidney injury — the ONTARGET trial confirmed this. Monitor serum potassium and kidney function (creatinine/eGFR) regularly in all patients on ACE inhibitors or ARBs — especially at initiation and dose escalation. Beta-blockers must not be stopped abruptly in patients with coronary artery disease — rebound angina, arrhythmia, or even heart attack can result from sudden withdrawal. NSAIDs (ibuprofen, naproxen, diclofenac) significantly raise blood pressure by approximately 3–5 mmHg on average, reduce the effectiveness of antihypertensive therapy, and increase the risk of acute kidney injury in combination with ACE inhibitors/ARBs — patients with hypertension should use paracetamol (acetaminophen) for pain relief instead. Concurrent use of multiple potassium-raising drugs (ACE inhibitor + potassium-sparing diuretic + potassium supplement) requires careful potassium monitoring. Some cold and flu remedies (containing pseudoephedrine or phenylephrine) raise blood pressure — avoid in hypertension.