High Blood Pressure Drugs: What Causes It and What Treats It

What Is High Blood Pressure and Why Does It Matter?

The ACC/AHA 2017 guideline defines hypertension as a sustained systolic blood pressure at or above 130 mmHg or diastolic at or above 80 mmHg, confirmed on at least two separate occasions. At those thresholds, arterial wall stress begins to damage the endothelium, the kidneys, and the left ventricle long before most people feel any symptom.

The scale of the problem

The CDC estimates that 116 million U.S. Adults, roughly 47% of the adult population, meet the 2017 ACC/AHA definition of hypertension [1]. Of those, only about 1 in 4 have their blood pressure adequately controlled [2]. Globally, the WHO attributes 7.5 million deaths per year directly to high blood pressure, making it the single largest attributable cause of premature mortality [3].

Why blood pressure numbers matter so much

A landmark meta-analysis published in The Lancet covering 1 million adults across 61 prospective studies found that each 20 mmHg rise in usual systolic BP doubles the risk of death from ischemic heart disease and stroke, an effect seen continuously from 115/75 mmHg upward with no apparent floor [4]. That graded relationship is why clinicians treat even stage 1 hypertension (130-139/80-89 mmHg) in patients with existing atherosclerotic cardiovascular disease.

How a diagnosis is made

A single elevated reading in a clinic does not confirm hypertension. White-coat hypertension, where BP rises in a medical setting but is normal elsewhere, affects up to 30% of people with apparent office hypertension [5]. The AHA recommends at least two measurements on two separate visits, or out-of-office verification via ambulatory blood pressure monitoring (ABPM), which averages readings over 24 hours and is considered the diagnostic gold standard by multiple guideline bodies [6].

Drugs and Substances That Cause or Worsen High Blood Pressure

Many prescription and over-the-counter agents are well-documented pressor agents. Recognizing them is often the fastest route to controlling previously resistant hypertension.

NSAIDs: the most common culprit

Non-steroidal anti-inflammatory drugs, including ibuprofen, naproxen, and celecoxib, inhibit prostaglandin synthesis in the kidney. This causes sodium and water retention and blunts the effect of most antihypertensive drug classes. A meta-analysis in the BMJ of 19 randomized trials (N=1,324) found that NSAIDs raised mean systolic BP by 3.3 mmHg on average, with the effect reaching 6.2 mmHg in patients already taking antihypertensives [7]. Even two standard doses of ibuprofen daily for one week can meaningfully attenuate ACE inhibitor efficacy.

Decongestants and stimulants

Pseudoephedrine and phenylephrine, standard ingredients in cold and sinus remedies, act as alpha-1 adrenergic agonists, constricting peripheral arteries. A randomized crossover trial published in Annals of Internal Medicine found that pseudoephedrine 60 mg raised systolic BP by 3.3 mmHg and heart rate by 2.8 bpm within one hour of dosing [8]. Patients with BP above 150/95 mmHg were excluded from that trial, so the pressor effect may be larger in the hypertensive population. Caffeine and ADHD medications (amphetamine salts, methylphenidate) also raise BP acutely, though tolerance to caffeine's pressor effect develops within days.

Hormonal contraceptives

Combined oral contraceptives (COCs) containing ethinyl estradiol raise systolic BP by 3-8 mmHg through estrogen-mediated increases in angiotensinogen and aldosterone [9]. The risk is dose-dependent and higher in women over 35 who smoke. The AHA and ACOG both recommend BP measurement before initiating COCs and reassessment at 3 months [9]. Progestin-only pills carry substantially lower pressor risk and are preferred in women with pre-existing hypertension.

Other common pressor agents

Several additional drug classes deserve attention in a hypertensive patient's medication list:

• Calcineurin inhibitors (cyclosporine, tacrolimus): raise BP in 50-80% of transplant recipients via renal vasoconstriction [10].
• Erythropoiesis-stimulating agents (epoetin alfa): increase red cell mass and vascular resistance; hypertension is listed as a black-box warning on the FDA prescribing information [11].
• Venlafaxine and SNRIs: dose-dependent increases in norepinephrine release raise BP by 2-4 mmHg at standard doses, occasionally more at high doses [12].
• Licorice root (glycyrrhizin): inhibits 11-beta-hydroxysteroid dehydrogenase, causing pseudo-hyperaldosteronism; case reports document BP exceeding 200/100 mmHg after prolonged supplementation [13].
• Cocaine and methamphetamine: catecholamine surges can cause hypertensive emergencies exceeding 180/120 mmHg acutely.

First-Line Drugs That Treat High Blood Pressure

The JNC-8 guidelines and the 2017 ACC/AHA guideline both endorse four major antihypertensive drug classes as first-line therapy for most patients: thiazide diuretics, ACE inhibitors, angiotensin receptor blockers (ARBs), and dihydropyridine calcium channel blockers (CCBs) [14].

Thiazide diuretics

Chlorthalidone and hydrochlorothiazide are the most prescribed antihypertensives in the United States. Chlorthalidone 12.5-25 mg daily is preferred over hydrochlorothiazide by most guidelines because its longer half-life (45-60 hours versus 8-15 hours) produces smoother 24-hour BP control. The ALLHAT trial (N=33,357), the largest antihypertensive outcomes trial ever conducted, found chlorthalidone superior to lisinopril and amlodipine in preventing heart failure and no worse on the primary composite outcome of fatal coronary heart disease and nonfatal MI [15]. The ACC/AHA 2017 guideline states: "Thiazide-type diuretics, particularly chlorthalidone, are recommended as a component of combination therapy in most patients with hypertension" [14].

ACE inhibitors and ARBs

ACE inhibitors (lisinopril, ramipril, enalapril) block the conversion of angiotensin I to angiotensin II, reducing vasoconstriction and aldosterone release. ARBs (losartan, valsartan, telmisartan) block the angiotensin II receptor directly. Both classes reduce systolic BP by 8-12 mmHg at standard doses [16]. ACE inhibitors carry a 10-15% incidence of dry cough from bradykinin accumulation; ARBs do not. In the ONTARGET trial (N=25,620), telmisartan was non-inferior to ramipril for the composite cardiovascular endpoint and produced fewer cases of cough and angioedema [17]. Both classes are first-choice agents in patients with diabetes or chronic kidney disease because of proven renoprotective effects independent of BP lowering.

Calcium channel blockers

Dihydropyridine CCBs, primarily amlodipine 5-10 mg daily, relax vascular smooth muscle by blocking L-type calcium channels. They lower systolic BP by 10-15 mmHg as monotherapy [18]. Amlodipine is the preferred CCB in most guidelines given its very long half-life (30-50 hours), once-daily dosing, and strong outcomes data. In ASCOT-BPLA (N=19,257), amlodipine-based therapy reduced the risk of fatal and nonfatal stroke by 23% compared with atenolol-based therapy (P<0.0001) [19].

Beta-blockers: a nuanced position

Beta-blockers (metoprolol succinate, carvedilol, bisoprolol) are no longer first-line for uncomplicated hypertension in most major guidelines. ASCOT-BPLA showed atenolol was inferior to amlodipine for stroke and new-onset diabetes [19]. Beta-blockers remain preferred or indicated when hypertension co-exists with heart failure with reduced ejection fraction, post-MI status, atrial fibrillation requiring rate control, or migraine prophylaxis.

Newer and Emerging Antihypertensive Options

Beyond the traditional four classes, several newer agents are moving into clinical practice, particularly for resistant hypertension and patients with metabolic comorbidities.

Mineralocorticoid receptor antagonists

Spironolactone 25-50 mg daily is the most effective add-on therapy for resistant hypertension, defined as BP above goal on three agents including a diuretic. In the PATHWAY-2 trial (N=335), spironolactone added as a fourth agent reduced home systolic BP by 8.7 mmHg more than placebo, outperforming bisoprolol and doxazosin [20]. The mechanism is aldosterone blockade, which addresses the sodium retention that underlies most resistant hypertension. Finerenone, a selective non-steroidal mineralocorticoid receptor antagonist, shows renal and cardiovascular benefits in patients with type 2 diabetes and chronic kidney disease in the FIDELIO-DKD trial (N=5,734) [21].

GLP-1 receptor agonists

Semaglutide (Ozempic, Wegovy) and other GLP-1 receptor agonists lower systolic BP by 3-6 mmHg as part of their cardiometabolic effect profile, an effect seen on top of existing antihypertensive regimens. In STEP-1 (N=1,961), semaglutide 2.4 mg produced 14.9% mean weight loss versus 2.4% with placebo at 68 weeks, accompanied by a 6.2 mmHg reduction in systolic BP [22]. The SELECT trial (N=17,604) confirmed a 20% reduction in major adverse cardiovascular events with semaglutide 2.4 mg in overweight adults with established cardiovascular disease, an effect partly mediated by BP reduction [23].

SGLT-2 inhibitors

Empagliflozin, dapagliflozin, and canagliflozin lower systolic BP by 3-5 mmHg through osmotic diuresis and natriuresis. In EMPA-REG OUTCOME (N=7,020), empagliflozin reduced cardiovascular death by 38% and hospitalization for heart failure by 35%, with a systolic BP reduction of 4 mmHg versus placebo [24]. The 2023 AHA/ACC guideline on heart failure now lists empagliflozin as a Class I recommendation for HFrEF regardless of diabetes status.

The Role of Lifestyle in Blood Pressure Management

Drug therapy does not replace lifestyle modification. The two work through different mechanisms and their effects add together.

Dietary interventions

The DASH (Dietary Approaches to Stop Hypertension) diet, rich in fruits, vegetables, low-fat dairy, and limited in sodium, reduced systolic BP by 11.4 mmHg in hypertensive participants and 3.5 mmHg in normotensive participants in the original DASH trial (N=459) [25]. Sodium restriction below 2,300 mg per day provides an additional 2-8 mmHg systolic reduction.

Physical activity

Aerobic exercise at 40-60% of VO2 max for 30 minutes on most days of the week lowers resting systolic BP by 4-9 mmHg, comparable to starting a low-dose antihypertensive agent [26]. Resistance training provides a smaller but additive 2-3 mmHg benefit.

Alcohol and sleep

Alcohol above 14 units per week raises systolic BP dose-dependently; reduction to below 7 units per week produces 3-4 mmHg systolic improvement [27]. Obstructive sleep apnea is present in approximately 30-40% of hypertensive patients and raises nocturnal BP substantially; CPAP treatment reduces 24-hour mean BP by 2-3 mmHg [28].

Resistant Hypertension: When Drugs Are Not Enough

Resistant hypertension is defined as BP above goal despite three maximally tolerated antihypertensive agents from different classes, including a diuretic. Truly resistant hypertension affects approximately 12-15% of all treated hypertensive patients [29].

Evaluation before adding a fourth agent

The first step is ruling out pseudo-resistance. Check medication adherence with urine drug screening, confirm white-coat effect is not inflating office readings, audit pressor medications (NSAIDs are the most common reversible cause), and screen for secondary causes including primary hyperaldosteronism (plasma aldosterone/renin ratio), renal artery stenosis (Doppler ultrasound), and obstructive sleep apnea [30].

Secondary hypertension causes by frequency

Primary hyperaldosteronism accounts for 5-10% of all hypertension cases and up to 20% of resistant cases [31]. Renovascular hypertension, pheochromocytoma, Cushing syndrome, and thyroid dysfunction make up most of the remainder. A 24-hour urine catecholamine panel and plasma metanephrines are appropriate when paroxysmal hypertension, headache, and diaphoresis co-occur.

Device-based therapies

Renal denervation using catheter-based radiofrequency ablation of the renal sympathetic nerves has re-emerged as a viable option after the SPYRAL HTN-OFF MED Key trial (N=331) showed a 7.9 mmHg reduction in 24-hour ambulatory systolic BP versus sham at 3 months (P<0.0001) [32]. The FDA approved the Symplicity Spyral system in November 2023 for patients with uncontrolled hypertension. Baroreflex activation therapy (barostim) is approved for patients with heart failure and may lower BP as a secondary effect.

Blood Pressure Goals by Patient Population

A single BP target does not apply to every patient. Targets differ based on age, comorbidities, and tolerance of adverse effects.

| Population | Systolic Goal | Diastolic Goal | Key Guideline | |---|---|---|---| | General adults (high CVD risk) | <130 mmHg | <80 mmHg | ACC/AHA 2017 [14] | | Adults 65 and older (ambulatory) | <130 mmHg | <80 mmHg | SPRINT data [33] | | Adults 65 and older (frail/high fall risk) | <140 mmHg | <90 mmHg | Clinical judgment | | CKD without proteinuria | <140 mmHg | <90 mmHg | KDIGO 2021 [34] | | CKD with proteinuria | <130 mmHg | <80 mmHg | KDIGO 2021 [34] | | Diabetes | <130 mmHg | <80 mmHg | ADA 2024 [35] | | Pregnancy (chronic hypertension) | <140 mmHg | <90 mmHg | ACOG 2020 [36] |

The SPRINT trial (N=9,361) deserves direct mention here. Targeting systolic BP below 120 mmHg reduced the composite of MI, ACS, stroke, heart failure, and cardiovascular death by 25% compared with a target below 140 mmHg, but increased rates of acute kidney injury (4.4% vs. 2.6%) and serious hypotension [33]. The ACC/AHA adopted a 130 mmHg target as a balance point after weighing those findings.

Monitoring, Safety, and When to Seek Care

Home monitoring protocols

The AHA recommends using a validated upper-arm oscillometric cuff, sitting quietly for 5 minutes before measurement, taking two readings one minute apart, and averaging the two [6]. Readings above 180/120 mmHg with chest pain, shortness of breath, or neurological symptoms constitute a hypertensive emergency requiring immediate emergency department care.

Laboratory monitoring on antihypertensives

Patients starting ACE inhibitors or ARBs should have serum creatinine and potassium checked within 2-4 weeks of initiation; a creatinine rise of up to 30% from baseline is acceptable and does not require drug discontinuation [37]. Thiazide diuretics cause hypokalemia in approximately 10-15% of patients; supplemental potassium or combination with a potassium-sparing agent may be needed. Spironolactone raises potassium and requires monitoring every 4-8 weeks during titration.

Drug interactions to know

ACE inhibitors combined with NSAIDs increase acute kidney injury risk by approximately 3-fold compared with either drug alone, a combination sometimes called the "triple whammy" when a diuretic is added [38]. Combining two renin-angiotensin-aldosterone system blockers (e.g., ACE inhibitor plus ARB) is not recommended after ONTARGET showed no cardiovascular benefit and significantly increased renal harm [17].

The ADA 2024 Standards of Medical Care state: "For patients with type 2 diabetes and hypertension, an ACE inhibitor or ARB is recommended as the antihypertensive agent of choice to reduce the risk of progression of diabetic kidney disease" [35].