Antihypertensives and Their Effects

Antihypertensives

• Most antihypertensives affect the renin-angiotensin system, a powerful vasoconstrictor
• Vasoconstriction increases blood pressure.
• Calcium channel blockers, beta blockers, and peripheral vasodilators decrease heart rate and/or blood pressure.
• When administering beta blockers and calcium channel blockers, check pulse and blood pressure.
• All antihypertensives can cause hypotension.
• Antihypertensives are used for hypertension, hypertensive emergencies, and to diagnose pheochromocytoma (a tumor of the adrenal glands that causes high blood pressure).

Adverse Effects

• Peripheral Vasodilators: Hypotension, dizziness, angina, headache, hirsutism (masculine hair distribution in females), nasal congestion, fatigue, sodium and water retention.
• Beta Blockers: Bradycardia, hypotension, heart failure, dizziness, arrhythmias, decreased libido, impotence, constipation, diarrhea.
• Central Acting Anti-Adrenergics: Drowsiness, sedation, headache, dry mouth, hypotension, syncope, fluid retention, constipation.
• Peripheral Acting Anti-Adrenergics: Headache, fatigue, hypotension, lethargy, dyspepsia (heartburn), headache.
• Alpha Adrenergics: Headache, fatigue, hypotension, sexual dysfunction, lack of energy.
• ACE Inhibitors: Cough, nausea, hypotension, headache, fatigue.
• Angiotensin II Receptor Antagonists: Diarrhea, abdominal pain, hypotension, fatigue, headache, lightheadedness, upper respiratory symptoms, cough.
• Hypertensive Emergency Drugs: Dizziness, weakness, nausea, vomiting, sodium and water retention, apprehensive feeling, headaches.

Drug Classes and Examples

• Beta Blockers: End in "olol" (e.g., Metoprolol, Atenolol, Propranolol)
• Calcium Channel Blockers: Examples include Diltiazem, Verapamil, Amlodipine
• Central Acting Anti-Adrenergics: Examples include Clonidine, Methyldopa
• Peripheral Acting Anti-Adrenergics: Examples include Guanabenz, Guanfacine
• Alpha Adrenergics: Examples include Prazosin, Terazosin, Doxazosin
• ACE Inhibitors: End in "pril" (e.g., Captopril, Enalapril, Lisinopril)
• Angiotensin II Receptor Antagonists: End in "sartan" (e.g., Losartan, Valsartan, Candesartan)
• Hypertensive Emergency Drugs: IV only, used in emergency rooms and CCUs (e.g., Nitroprusside, Nicardipine, Fenoldopam)

Administration and Monitoring

• Always check blood pressure before administering antihypertensives.
• Monitor for adverse effects and notify the doctor if necessary.
• Be aware of orthostatic hypotension and have the patient dangle their feet before getting out of bed.
• Do not stop taking antihypertensives abruptly.
• Teach patients to recognize the signs of heart failure (sudden weight gain, fluid retention, edema, shortness of breath).
• Encourage patients to follow up with a physician for regular blood pressure checks.

Important Considerations

• Aldomet (methyldopa) can turn urine brown.
• Regitine (phentolamine) is an alpha adrenergic blocker.
• Coreg (carvedilol) is a popular alpha-beta blocker.
• Many antihypertensives can cause sexual dysfunction and lack of energy.
• Over-the-counter preparations can interact with antihypertensives and increase blood pressure; check with a healthcare provider.

Antihypertensives

• Antihypertensives primarily target the renin-angiotensin system, a potent vasoconstrictor, to lower blood pressure.
• Vasoconstriction elevates blood pressure.
• Calcium channel blockers, beta blockers, and peripheral vasodilators diminish heart rate and/or blood pressure.
• Always monitor pulse and blood pressure when administering beta blockers and calcium channel blockers.
• All antihypertensives can cause hypotension.
• Antihypertensives find application in managing hypertension, hypertensive emergencies, and facilitating the diagnosis of pheochromocytoma.

Adverse Effects

• Peripheral Vasodilators: Common side effects include hypotension, dizziness, angina, headache, hirsutism, nasal congestion, fatigue, and sodium and water retention.
• Beta Blockers: Can cause bradycardia, hypotension, heart failure, dizziness, arrhythmias, decreased libido, impotence, constipation, and diarrhea.
• Central Acting Anti-Adrenergics: Can cause drowsiness, sedation, headache, dry mouth, hypotension, syncope, fluid retention, and constipation.
• Peripheral Acting Anti-Adrenergics: Can cause headache, fatigue, hypotension, lethargy, dyspepsia, and headache.
• Alpha Adrenergics: Can cause headache, fatigue, hypotension, sexual dysfunction, and lack of energy.
• ACE Inhibitors: Can cause cough, nausea, hypotension, headache, and fatigue.
• Angiotensin II Receptor Antagonists: Can cause diarrhea, abdominal pain, hypotension, fatigue, headache, lightheadedness, upper respiratory symptoms, and cough.
• Hypertensive Emergency Drugs: Can cause dizziness, weakness, nausea, vomiting, sodium and water retention, apprehensive feeling, and headaches.

Drug Classes and Examples

• Beta Blockers: Typically end in "olol" (e.g., Metoprolol, Atenolol, Propranolol).
• Calcium Channel Blockers: Examples include Diltiazem, Verapamil, and Amlodipine.
• Central Acting Anti-Adrenergics: Examples include Clonidine and Methyldopa.
• Peripheral Acting Anti-Adrenergics: Examples include Guanabenz and Guanfacine.
• Alpha Adrenergics: Examples include Prazosin, Terazosin, and Doxazosin.
• ACE Inhibitors: Typically end in "pril" (e.g., Captopril, Enalapril, Lisinopril).
• Angiotensin II Receptor Antagonists: Typically end in "sartan" (e.g., Losartan, Valsartan, Candesartan).
• Hypertensive Emergency Drugs: Administered intravenously (IV) only and used in emergency rooms and cardiac care units (CCUs) (e.g., Nitroprusside, Nicardipine, Fenoldopam).

Administration and Monitoring

• Always check blood pressure before administering antihypertensives.
• Monitor for adverse effects and inform the doctor if necessary.
• Be aware of orthostatic hypotension, advising patients to dangle their feet before getting out of bed.
• Do not stop taking antihypertensives abruptly.
• Educate patients to recognize signs of heart failure such as sudden weight gain, fluid retention, edema, and shortness of breath.
• Encourage patients to follow up with a physician for regular blood pressure checks.

Important Considerations

• Aldomet (methyldopa) can result in brown urine.
• Regitine (phentolamine) is an alpha adrenergic blocker.
• Coreg (carvedilol) is a popular alpha-beta blocker.
• Many antihypertensives can lead to sexual dysfunction and lack of energy.
• Over-the-counter preparations can interact with antihypertensives and increase blood pressure; consult with a healthcare provider.