💊Pharmacology for Nurses Unit 18 – Hypertension & Angina Medications

Key Concepts and Definitions

• Hypertension, also known as high blood pressure, occurs when the force of blood against the artery walls is consistently too high
• Angina, a type of chest pain, is caused by reduced blood flow to the heart muscle due to narrowed or blocked coronary arteries
• Systolic blood pressure measures the pressure in the arteries when the heart beats, while diastolic blood pressure measures the pressure between beats
• Antihypertensive medications are used to lower blood pressure and reduce the risk of complications such as heart attack, stroke, and kidney damage
• Antianginal medications are used to relieve and prevent angina symptoms by improving blood flow to the heart muscle
• Essential hypertension has no identifiable cause and accounts for the majority of hypertension cases, while secondary hypertension is caused by an underlying condition
• Stable angina occurs predictably with exertion or stress, while unstable angina occurs unexpectedly and may indicate a more serious condition

Pathophysiology Overview

• Hypertension develops when the body's normal blood pressure regulation mechanisms are disrupted, leading to persistently elevated pressure in the arteries
• Factors contributing to hypertension include increased cardiac output, increased peripheral vascular resistance, and reduced arterial compliance
• Over time, untreated hypertension can lead to damage and remodeling of the blood vessels, increasing the risk of complications such as atherosclerosis and aneurysms
• Angina occurs when the heart muscle does not receive enough oxygen-rich blood to meet its metabolic demands, often due to atherosclerotic plaques in the coronary arteries
• Stable angina is typically triggered by physical exertion or emotional stress, which increases the heart's oxygen demand beyond what the narrowed arteries can supply
• Unstable angina may be caused by the rupture of an atherosclerotic plaque, leading to the formation of a blood clot that further restricts blood flow to the heart
• Prinzmetal's angina, a rare form of angina, is caused by coronary artery spasms that temporarily reduce blood flow to the heart muscle

Types of Hypertension & Angina Medications

• Diuretics (thiazides, loop diuretics, potassium-sparing diuretics) help lower blood pressure by promoting the excretion of excess fluid and sodium from the body
• Beta-blockers (metoprolol, atenolol) reduce heart rate and cardiac output, lowering blood pressure and reducing the heart's oxygen demand
• ACE inhibitors (lisinopril, ramipril) relax blood vessels and decrease blood volume by inhibiting the production of angiotensin II, a vasoconstrictor
• Angiotensin II receptor blockers (ARBs) (losartan, valsartan) work similarly to ACE inhibitors but directly block the action of angiotensin II at its receptor
• Calcium channel blockers (amlodipine, diltiazem) relax blood vessels and reduce the heart's workload by inhibiting calcium influx into vascular smooth muscle and cardiac cells
• Nitrates (nitroglycerin, isosorbide dinitrate) dilate coronary arteries and reduce venous return to the heart, improving blood flow and reducing oxygen demand
• Ranolazine, an antianginal medication, works by inhibiting the late sodium current in cardiac cells, reducing calcium overload and improving myocardial function

Mechanism of Action

• Diuretics work by inhibiting the reabsorption of sodium and water in the kidneys, leading to increased urine output and reduced blood volume
  • Thiazide diuretics (hydrochlorothiazide) inhibit the Na+/Cl- cotransporter in the distal convoluted tubule
  • Loop diuretics (furosemide) inhibit the Na+/K+/2Cl- cotransporter in the thick ascending limb of the loop of Henle
  • Potassium-sparing diuretics (spironolactone) block aldosterone receptors or inhibit sodium channels in the collecting duct
• Beta-blockers bind to and block beta-adrenergic receptors in the heart and blood vessels, reducing the effects of sympathetic nervous system activation
  • Selective beta-1 blockers (metoprolol) primarily target cardiac beta-1 receptors, while non-selective beta blockers (propranolol) also affect beta-2 receptors in the lungs and blood vessels
• ACE inhibitors block the conversion of angiotensin I to angiotensin II by inhibiting angiotensin-converting enzyme (ACE)
  • Reduced angiotensin II levels lead to vasodilation, decreased aldosterone secretion, and reduced sympathetic nervous system activity
• ARBs selectively block angiotensin II type 1 (AT1) receptors, preventing the vasoconstrictor and aldosterone-secreting effects of angiotensin II
• Calcium channel blockers inhibit voltage-gated calcium channels, reducing calcium influx into vascular smooth muscle and cardiac cells
  • Dihydropyridines (amlodipine) primarily affect vascular smooth muscle, while non-dihydropyridines (diltiazem, verapamil) also have significant effects on cardiac conduction and contractility
• Nitrates release nitric oxide (NO), which activates guanylate cyclase and increases cyclic guanosine monophosphate (cGMP) levels in vascular smooth muscle cells
  • Increased cGMP leads to vasodilation, reduced venous return, and improved coronary blood flow
• Ranolazine inhibits the late sodium current in cardiac cells, reducing calcium overload and improving myocardial relaxation and diastolic function

Indications and Usage

• Hypertension medications are used to lower blood pressure and reduce the risk of complications such as heart attack, stroke, and kidney damage
  • First-line treatments often include thiazide diuretics, ACE inhibitors, ARBs, and calcium channel blockers
  • Beta-blockers may be preferred in patients with certain comorbidities (coronary artery disease, heart failure)
  • Combination therapy with multiple drug classes is often necessary to achieve optimal blood pressure control
• Antianginal medications are used to prevent and relieve symptoms of angina pectoris
  • Nitrates (nitroglycerin) are used for acute relief of angina symptoms and prophylaxis before activities that may trigger angina
  • Beta-blockers and calcium channel blockers are used for long-term prevention of angina episodes
  • Ranolazine may be used as an adjunctive therapy in patients who continue to experience angina despite treatment with other medications
• Hypertension and angina medications may also be used in the management of related conditions
  • ACE inhibitors and ARBs are often used in patients with diabetes or chronic kidney disease to slow disease progression
  • Beta-blockers and ACE inhibitors are important components of heart failure treatment regimens
  • Calcium channel blockers may be used to treat certain arrhythmias (supraventricular tachycardia, atrial fibrillation)

Dosage and Administration

• Dosages for hypertension and angina medications vary depending on the specific drug, indication, and patient factors (age, renal function, comorbidities)
  • Thiazide diuretics (hydrochlorothiazide): Typical starting dose is 12.5-25 mg once daily, with a maximum dose of 50 mg daily
  • ACE inhibitors (lisinopril): Typical starting dose is 10 mg once daily, with a usual maintenance dose of 20-40 mg daily
  • ARBs (losartan): Typical starting dose is 50 mg once daily, with a usual maintenance dose of 50-100 mg daily
  • Calcium channel blockers (amlodipine): Typical starting dose is 2.5-5 mg once daily, with a usual maintenance dose of 5-10 mg daily
• Beta-blockers (metoprolol): Typical starting dose for hypertension is 50-100 mg daily, while angina dosing may range from 50-400 mg daily depending on the formulation
• Nitrates (nitroglycerin): Sublingual tablets or spray (0.3-0.6 mg) are used for acute angina relief, while extended-release formulations are used for prophylaxis
• Ranolazine: Typical starting dose is 500 mg twice daily, with a maximum dose of 1000 mg twice daily
• Most hypertension and angina medications can be taken orally with or without food
  • Short-acting nitrates (sublingual nitroglycerin) should be used as needed for acute angina symptoms
  • Extended-release formulations should be swallowed whole and not crushed or chewed
• Dose adjustments may be necessary based on patient response, adverse effects, and changes in renal or hepatic function
  • ACE inhibitors, ARBs, and certain beta-blockers may require dose reduction in patients with renal impairment
  • Calcium channel blockers and ranolazine may require dose adjustment in patients with hepatic dysfunction

Side Effects and Adverse Reactions

• Diuretics: Common side effects include electrolyte imbalances (hypokalemia, hyponatremia), hyperuricemia, and glucose intolerance
  • Thiazide diuretics may cause orthostatic hypotension, especially in older adults
  • Loop diuretics may cause ototoxicity (hearing loss, tinnitus) at high doses
• Beta-blockers: Common side effects include fatigue, bradycardia, hypotension, and cold extremities
  • Non-selective beta-blockers may cause bronchospasm in patients with asthma or COPD
  • Abrupt discontinuation may lead to rebound hypertension or angina
• ACE inhibitors and ARBs: Common side effects include cough (ACE inhibitors), hyperkalemia, and renal dysfunction
  • Angioedema is a rare but potentially serious adverse reaction
  • Fetal toxicity may occur with second and third trimester exposure
• Calcium channel blockers: Common side effects include peripheral edema, headache, and flushing
  • Non-dihydropyridines (diltiazem, verapamil) may cause bradycardia and heart block
• Nitrates: Common side effects include headache, flushing, and hypotension
  • Tolerance may develop with continuous use, reducing antianginal efficacy
• Ranolazine: Common side effects include dizziness, headache, and constipation
  • QT prolongation may occur, especially at higher doses or in combination with other QT-prolonging drugs
• Rare but serious adverse reactions for all classes may include allergic reactions, hepatotoxicity, and blood dyscrasias
• Patients should be monitored for adverse effects and informed of potential symptoms to report to their healthcare provider

Drug Interactions

• Diuretics: NSAIDs may reduce the efficacy of diuretics and increase the risk of renal dysfunction
  • Thiazide diuretics may enhance the hypotensive effects of other antihypertensive medications
  • Loop diuretics may increase the risk of ototoxicity when used with other ototoxic drugs (aminoglycosides)
• Beta-blockers: Calcium channel blockers (diltiazem, verapamil) may increase the risk of bradycardia and heart block when used with beta-blockers
  • Beta-blockers may mask the symptoms of hypoglycemia in patients with diabetes
  • CYP2D6 inhibitors (fluoxetine, paroxetine) may increase the levels and effects of certain beta-blockers (metoprolol, propranolol)
• ACE inhibitors and ARBs: Concomitant use with potassium-sparing diuretics or potassium supplements may increase the risk of hyperkalemia
  • NSAIDs may reduce the antihypertensive effects of ACE inhibitors and ARBs and increase the risk of renal dysfunction
• Calcium channel blockers: CYP3A4 inhibitors (ketoconazole, clarithromycin) may increase the levels and effects of calcium channel blockers
  • Grapefruit juice may increase the bioavailability of certain calcium channel blockers (felodipine, nifedipine)
• Nitrates: Phosphodiesterase-5 (PDE-5) inhibitors (sildenafil, tadalafil) may potentiate the hypotensive effects of nitrates and are contraindicated
• Ranolazine: CYP3A4 inhibitors may significantly increase ranolazine levels and the risk of QT prolongation
  • P-glycoprotein inhibitors (verapamil, cyclosporine) may also increase ranolazine exposure
• Healthcare providers should review patients' medication lists for potential drug interactions and adjust therapy as needed
  • Patients should be advised to inform their providers of all prescription, over-the-counter, and herbal medications they are taking

Nursing Considerations

• Assess patients' blood pressure, heart rate, and angina symptoms before and during treatment with hypertension and angina medications
  • Monitor for signs of hypotension, bradycardia, or worsening angina
  • Assess for the presence of comorbidities (diabetes, renal dysfunction) that may impact medication selection and dosing
• Administer medications as prescribed and educate patients on the proper use, storage, and disposal of their medications
  • Teach patients how to use sublingual nitroglycerin for acute angina episodes
  • Emphasize the importance of taking medications consistently and not abruptly discontinuing without consulting their healthcare provider
• Monitor patients for adverse effects and drug interactions
  • Perform regular laboratory tests (electrolytes, renal function) as indicated for specific medication classes
  • Assess for signs of allergic reactions, hepatotoxicity, or blood dyscrasias
• Provide patient education on lifestyle modifications for managing hypertension and angina
  • Encourage a healthy diet, regular exercise, stress management, and smoking cessation
  • Teach patients how to properly measure and record their blood pressure at home
• Collaborate with the healthcare team to develop and implement individualized treatment plans
  • Communicate any changes in patients' conditions or medication responses to the appropriate providers
  • Participate in medication reconciliation to ensure accurate and up-to-date medication lists
• Promote medication adherence through patient education, reminders, and assistance with obtaining refills
  • Address any barriers to adherence (cost, side effects, complexity of regimen) and work with patients to find solutions
  • Encourage patients to use pill boxes, alarms, or smartphone apps to help them remember to take their medications as prescribed

Patient Education

• Explain the purpose, benefits, and potential risks of prescribed hypertension and angina medications
  • Emphasize the importance of taking medications as directed and not stopping without consulting their healthcare provider
  • Discuss the expected onset and duration of action for each medication
• Teach patients how to properly take their medications, including any specific timing, storage, or administration requirements
  • Demonstrate how to use sublingual nitroglycerin for acute angina episodes and when to seek emergency medical attention
  • Advise patients to swallow extended-release formulations whole and not to crush or chew them
• Educate patients on common side effects and what to do if they occur
  • Encourage patients to report any severe, persistent, or bothersome side effects to their healthcare provider
  • Provide guidance on managing minor side effects (e.g., taking diuretics in the morning to avoid nocturia)
• Discuss the importance of lifestyle modifications in managing hypertension and angina
  • Encourage a diet rich in fruits, vegetables, whole grains, and low-fat dairy products, and low in sodium and saturated fats
  • Recommend regular aerobic exercise (at least 150 minutes per week) as tolerated and approved by their healthcare provider
  • Offer resources for stress management techniques (deep breathing, meditation, yoga) and smoking cessation programs
• Teach patients how to properly measure and record their blood pressure at home
  • Provide instructions on selecting an appropriate home blood pressure monitor and cuff size
  • Demonstrate the correct technique for measuring blood pressure and recording results
• Emphasize the importance of regular follow-up appointments and adherence to monitoring tests
  • Encourage patients to bring their home blood pressure records and medication lists to each appointment
  • Advise patients to promptly report any changes in their condition or new symptoms to