Antihypertensives

See Mechanism of Action of Select Antihypertensives table.

Pharmacologic Profile

General Use

Treatment of hypertension. Parenteral products are used in the treatment of hypertensive emergencies. Oral treatment should be initiated as soon as possible and individualized to ensure adherence and compliance for long-term therapy.

General Action and Information

MECHANISM OF ACTION OF SELECT ANTIHYPERTENSIVES

DRUG	MECHANISM
Acebutolol, atenolol, betaxolol, bisoprolol, carvedilol, labetalol, metoprolol, nadolol, nebivolol, pindolol, propranolol, and timolol	Beta blockers (selective: acebutolol, atenolol, betaxolol, bisoprolol, metoprolol, and nebivolol; nonselective: carvedilol, labetalol, nadolol, pindolol, propranolol, and timolol)
Amlodipine, diltiazem, felodipine, isradipine, nicardipine, nifedipine, nisoldipine, and verapamil	Calcium channel blockers (dihydropyridine: amlodipine, felodipine, isradipine, nicardipine, nifedipine, and nisoldipine; nondihydropyridine: diltiazem and verapamil)
Azilsartan, candesartan, irbesartan, losartan, olmesartan, telmisartan, and valsartan	Angiotensin II receptor blockers (ARBs)
Benazepril, captopril, enalapril/enalaprilat, fosinopril, lisinopril, moexipril, perindopril, quinapril, ramipril, and trandolapril	Angiotensin-converting enzyme (ACE) inhibitors
Chlorothiazide, chlorthalidone, hydrochlorothiazide, and metolazone	Thiazide diuretics
Doxazosin, prazosin, and terazosin	Alpha₁ receptor antagonists
Eplerenone and spironolactone	Mineralocorticoid receptor antagonists
Hydralazine and nitroprusside	Direct-acting vasodilators
Aprocitentan	Endothelin receptor antagonist
Clonidine	Centrally acting alpha₂ receptor agonist

Contraindications

Hypersensitivity to individual agents.

Precautions

Choose agents carefully in pregnancy and during lactation. ACE inhibitors and ARBs should be avoided during pregnancy. Clonidine and beta blockers should be used only in patients who are compliant with their medications because abrupt discontinuation of these agents may result in rapid and excessive ↑ in BP (rebound phenomenon). Thiazide and loop diuretics may ↑ the risk of hyperglycemia and hyperuricemia. Hydralazine may cause tachycardia if used alone and are commonly used in combination with beta blockers; it may also cause sodium and water retention and is usually combined with a diuretic.

Interactions

Many drugs can negate the therapeutic effectiveness of antihypertensives, including NSAIDs, sympathomimetics, decongestants, appetite suppressants, SNRIs, and MAO inhibitors. Hypokalemia from diuretics may ↑ the risk of digoxin toxicity. Potassium supplements and potassium-sparing diuretics may cause hyperkalemia when used with ACE inhibitors or ARBs. ACE inhibitors, ARBs, and diuretics may ↑ the risk of lithium toxicity. Digoxin, ivabradine, and clonidine may ↑ the risk of bradycardia when used with beta blockers, verapamil, or diltiazem.

Nursing Implications

Assessment

Monitor BP and HR frequently during dosage adjustment and periodically throughout therapy.
Monitor intake and output and daily weight with use of diuretics.

Implementation

Many antihypertensives are available as combination products to enhance compliance (see Combination Drugs).

Patient/Family Teaching

Instruct patient to continue taking medication, even if feeling well. Abrupt withdrawal may cause rebound hypertension. Medication controls but does not cure hypertension.
Encourage patient to comply with additional interventions for hypertension (weight ↓, low-sodium diet, regular exercise, discontinuation of smoking, moderation of alcohol consumption, stress management).
Instruct patient and family on proper technique for monitoring BP. Advise them to check BP weekly and report significant changes.
Caution patient to make position changes slowly to minimize orthostatic hypotension. Advise patient that exercise or hot weather may enhance hypotensive effects.
Advise patient to consult health care provider before taking any OTC medications, especially cold remedies.
Advise patient to inform health care provider of medication regimen before treatment or surgery.
Patients taking ACE inhibitors or ARBs should notify health care provider if pregnancy is planned or suspected.
Emphasize the importance of follow-up exams to monitor progress.

Evaluation/Desired Outcomes