Pharmacologic Profile

General Use

Treatment of hypertension of many causes, most commonly essential 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. Therapy is initiated with agents having minimal side effects. When such therapy fails, more potent drugs with different side effects are added in an effort to control BP while causing minimal patient discomfort.

General Action and Information

As a group, the antihypertensives are used to lower BP to a normal level (<130–140 systolic and <80–90 mm Hg diastolic) or to the lowest level tolerated. The goal of antihypertensive therapy is prevention of end-organ damage. Antihypertensives are classified into groups according to their site of action. These include alpha-1 receptor antagonists, centrally-acting alpha-adrenergic agonists; beta blockers; vasodilators; ACE inhibitors; angiotensin II receptor blockers (ARBs); calcium channel blockers; renin inhibitors; and diuretics. Hypertensive emergencies may be managed with parenteral agents, such as nitroprusside, nicardipine, or beta blockers (e.g. esmolol, labetalol).

Contraindications

Hypersensitivity to individual agents.

Precautions

Choose agents carefully in pregnancy and during lactation. ACE inhibitors, ARBs, and aliskiren should be avoided during pregnancy. Centrally acting alpha-adrenergic agonists 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. Vasodilators may cause tachycardia if used alone and are commonly used in combination with beta blockers. Some antihypertensives (e.g. hydralazine, minoxidil) cause sodium and water retention and are 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, ARBs, or aliskiren.

Nursing Implications

Assessment

• Monitor BP and pulse frequently during dosage adjustment and periodically throughout therapy.
• Monitor intake and output ratios and daily weight with use of diuretics.
• Monitor frequency of prescription refills to determine compliance.

Potential Nursing Diagnoses

• Ineffective tissue perfusion (Indications)
• Deficient knowledge related to disease processes and medication regimen (Patient/Family Teaching)
• Noncompliance (Patient/Family Teaching)

Implementation

• Many antihypertensives are available as combination products to enhance compliance (see Appendix [not included in this PDA edition]).

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 reduction, low-sodium diet, regular exercise, discontinuation of smoking, moderation of alcohol consumption, and 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 professional before taking any OTC medications, especially cold remedies.
• Advise patient to inform health care professional of medication regimen before treatment or surgery.
• Patients taking ACE inhibitors, ARBs, or aliskiren should notify health care professional if pregnancy is planned or suspected.
• Emphasize the importance of follow-up exams to monitor progress.

Evaluation/Desired Outcomes

• Decrease in BP.