NUR521 Module 4: Cardiovascular Hemodynamics
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Questions and Answers

What is the result of long-term use of nifedipine?

  • No significant effect on cardiovascular outcomes
  • Increased rates of coronary angiography and coronary bypass surgery
  • Reduced rates of overt heart failure, coronary angiography, and coronary bypass surgery (correct)
  • Reduced rates of stroke, myocardial infarction, and death

    • Why is nifedipine preferred over verapamil for certain patients?

  • Due to its stronger vasodilatory effects
  • Because it causes minimal blockade of calcium channels in the heart (correct)
  • Because it is more effective in reducing blood pressure
  • Because it is a newer medication with fewer side effects

    • What is the mechanism of action of hydralazine?

  • Dilates arterioles and decreases peripheral resistance (correct)
  • Constricts arterioles and increases peripheral resistance
  • Constricts veins and decreases peripheral resistance
  • Dilates veins and increases peripheral resistance

    • What is a common combination therapy used with hydralazine?

    <p>With beta blockers to prevent reflex tachycardia</p> Signup and view all the answers

    What is a contraindication for the use of hydralazine?

    <p>Coronary artery disease</p> Signup and view all the answers

    What is a key feature of heart failure?

    <p>Ventricular dysfunction and reduced cardiac output</p> Signup and view all the answers

    What is the main mechanism of action of Triamterene?

    <p>It directly inhibits Na-K exchange in the distal nephron</p> Signup and view all the answers

    What is the primary indication for the use of Furosemide?

    <p>Rapid or massive mobilization of fluid</p> Signup and view all the answers

    Which diuretic is contraindicated with digoxin, lithium, and other hypertension medications?

    <p>Thiazide</p> Signup and view all the answers

    What is a common adverse effect of Loop diuretics?

    <p>Hypokalemia</p> Signup and view all the answers

    What is a precaution to be taken when prescribing Furosemide to patients over 65?

    <p>Use with caution due to higher risk of hyponatremia</p> Signup and view all the answers

    What is a unique feature of Spironolactone?

    <p>It blocks the action of aldosterone</p> Signup and view all the answers

    What is a consideration when choosing a diuretic for a patient with renal disease?

    <p>The patient's renal function</p> Signup and view all the answers

    What is a potential adverse effect of Spironolactone in animal studies?

    <p>Tumors</p> Signup and view all the answers

    What is the primary mechanism of action of digoxin in treating CHF?

    <p>Increasing myocardial contraction force</p> Signup and view all the answers

    What is a common adverse effect of digoxin that can increase the risk of dysrhythmia?

    <p>Hypokalemia</p> Signup and view all the answers

    What is a lifestyle change that can help manage heart failure?

    <p>Eating a healthy diet</p> Signup and view all the answers

    What is the term for heart failure that occurs when the left ventricle cannot relax properly?

    <p>Heart failure with preserved ejection fraction (HFpEF)</p> Signup and view all the answers

    What is a sign of right-sided heart failure?

    <p>Liver congestion</p> Signup and view all the answers

    What is the primary goal of statin therapy?

    <p>Reducing cholesterol levels</p> Signup and view all the answers

    What is a complication of left-sided heart failure?

    <p>Pulmonary edema</p> Signup and view all the answers

    What is the term for heart failure that occurs when the left ventricle cannot pump blood efficiently?

    <p>Heart failure with reduced ejection fraction (HFrEF)</p> Signup and view all the answers

    What percentage of filtered sodium and chloride is reabsorbed at the PCT?

    <p>65%</p> Signup and view all the answers

    What is the primary function of the descending limb of the loop of Henle?

    <p>Formation of concentrated urine</p> Signup and view all the answers

    What is the primary function of aldosterone in the distal nephron?

    <p>Exchange of sodium for potassium</p> Signup and view all the answers

    What percentage of filtered sodium and chloride is reabsorbed in the early segment of the distal convoluted tubule?

    <p>10%</p> Signup and view all the answers

    What is the tonicity of the urine after passing through the loop of Henle?

    <p>1200 mOsm/L</p> Signup and view all the answers

    In which segment of the nephron is solutes and water reabsorbed at equal ratios?

    <p>PCT</p> Signup and view all the answers

    What is the primary hormone regulating the final concentration of urine in the distal nephron?

    <p>Antidiuretic hormone</p> Signup and view all the answers

    What is the primary function of the distal nephron?

    <p>Regulation of urine concentration and potassium exchange</p> Signup and view all the answers

    What is the preferred approach to treating type 2 diabetes?

    <p>Guiding treatment based on person-centered factors, such as comorbidities and lifestyle</p> Signup and view all the answers

    When is early introduction of insulin therapy considered in type 2 diabetes management?

    <p>When there is evidence of ongoing catabolism, hyperglycemic symptoms, or high A1C levels</p> Signup and view all the answers

    What is the benefit of using an ACE inhibitor or ARB in type 2 diabetes management?

    <p>Reducing the risk of diabetic nephropathy</p> Signup and view all the answers

    What is the preferred approach to managing diabetic hypertension?

    <p>Using ACE inhibitors or ARBs as the primary medication</p> Signup and view all the answers

    What is a consideration for older adults with type 2 diabetes?

    <p>De-intensifying treatment goals to reduce hypoglycemia risk</p> Signup and view all the answers

    What is the A1C target goal for older adults with type 2 diabetes?

    <p>Individualized based on patient factors</p> Signup and view all the answers

    In African Americans, which antihypertensive medication class is less effective compared to Caucasians?

    <p>β blockers</p> Signup and view all the answers

    What is the preferred antihypertensive medication class for patients with hypertension and diabetes?

    <p>ACEIs and ARBs</p> Signup and view all the answers

    In patients with hypertension and chronic kidney disease, which diuretic is avoided?

    <p>Thiazide diuretic</p> Signup and view all the answers

    What is a benefit of using ACEIs and ARBs in patients with diabetes?

    <p>They can slow the progression of renal damage and reduce albuminuria</p> Signup and view all the answers

    What is a mechanism of action of ACEIs?

    <p>Blocking the conversion of angiotensin I to II</p> Signup and view all the answers

    What is a potential adverse effect of ACEIs?

    <p>Cough</p> Signup and view all the answers

    What is a unique benefit of ACEIs in patients with comorbid conditions?

    <p>They can slow the progression of renal damage and reduce albuminuria</p> Signup and view all the answers

    What is a consideration when prescribing a direct renin inhibitor?

    <p>The risk of hyperkalemia</p> Signup and view all the answers

    What is the primary indication for the use of Triamterene?

    <p>Hypertension and edema</p> Signup and view all the answers

    Which of the following diuretics requires a minimum of 20-30mL/min of renal function to work effectively?

    <p>Thiazide</p> Signup and view all the answers

    What is a common adverse effect of Loop diuretics, such as Furosemide?

    <p>Hypokalemia</p> Signup and view all the answers

    Which of the following diuretics is used to counteract K-wasting effects?

    <p>Spironolactone</p> Signup and view all the answers

    What is a consideration when choosing a diuretic for a patient with hypertension?

    <p>Renal function</p> Signup and view all the answers

    What is a potential adverse effect of Spironolactone in animal studies?

    <p>Tumors</p> Signup and view all the answers

    Which of the following diuretics is used in combination with Lasix to augment its effects?

    <p>Triamterene</p> Signup and view all the answers

    What is a common adverse effect of all diuretics?

    <p>Profound diuresis with fluid and electrolyte depletion</p> Signup and view all the answers

    What is the primary effect of aldosterone on the distal nephron?

    <p>Retention of sodium and excretion of potassium</p> Signup and view all the answers

    Which of the following diuretics acts in the early segment of the distal convoluted tubule?

    <p>Hydrochlorothiazide</p> Signup and view all the answers

    What is the primary mechanism of action of Spironolactone?

    <p>Inhibiting the action of aldosterone in the distal nephron</p> Signup and view all the answers

    What is the effect of aldosterone on potassium in the distal nephron?

    <p>Excretion of potassium</p> Signup and view all the answers

    Which of the following diuretics is known as a potassium-sparing diuretic?

    <p>Spironolactone</p> Signup and view all the answers

    What is the primary effect of Furosemide on the nephron?

    <p>Blocks reabsorption of sodium and chloride in the loop of Henle</p> Signup and view all the answers

    What is the effect of aldosterone on sodium in the distal nephron?

    <p>Retention of sodium</p> Signup and view all the answers

    What is the benefit of using nifedipine over verapamil in patients with AV block, heart failure, bradycardia, or sick sinus syndrome?

    <p>It is less likely to exacerbate these conditions.</p> Signup and view all the answers

    What is the primary use of hydralazine in the treatment of heart failure?

    <p>To reduce afterload for a short time in congestive heart failure.</p> Signup and view all the answers

    What is the primary mechanism of action of Hydrochlorothiazide?

    <p>Blocking the reabsorption of sodium and chloride in the distal convoluted tubule</p> Signup and view all the answers

    Why is hydralazine usually combined with a beta blocker?

    <p>To prevent reflex tachycardia.</p> Signup and view all the answers

    What is a potential risk for older adults taking hydralazine?

    <p>High risk of falls due to polypharmacy and orthostatic hypotension.</p> Signup and view all the answers

    What is a characteristic of heart failure?

    <p>Ventricular dysfunction, reduced cardiac output, insufficient tissue perfusion, and fluid accumulation.</p> Signup and view all the answers

    What is an important aspect of patient education for those taking nifedipine?

    <p>Recording anginal episodes, blood pressure, and adverse effects.</p> Signup and view all the answers

    What is the primary mechanism of action of eplerenone?

    <p>Selective blockage of aldosterone receptors</p> Signup and view all the answers

    What is the contraindication for the use of eplerenone in patients with diabetes?

    <p>Microalbuminuria</p> Signup and view all the answers

    What is the primary use of calcium channel blockers (CCBs)?

    <p>Treatment of angina pectoris and cardiac arrhythmias</p> Signup and view all the answers

    What is the adverse effect of CCBs that is more common in older adults?

    <p>Eczematous rash</p> Signup and view all the answers

    When would you choose verapamil over diltiazem?

    <p>When treating infants</p> Signup and view all the answers

    What is the effect of eplerenone on potassium levels?

    <p>Increased potassium levels</p> Signup and view all the answers

    What is the benefit of adding an aldosterone antagonist to heart failure therapy?

    <p>Reduced blood volume and pressure</p> Signup and view all the answers

    What is the contraindication for the use of CCBs in patients with heart block?

    <p>All of the above</p> Signup and view all the answers

    Where is a large fraction (about 65%) of filtered sodium and chloride reabsorbed?

    <p>PCT</p> Signup and view all the answers

    What is the primary function of the descending limb of the loop of Henle?

    <p>Formation of concentrated urine</p> Signup and view all the answers

    What determines the final concentration of the urine in the distal nephron?

    <p>Antidiuretic hormone (ADH)</p> Signup and view all the answers

    Where is solutes and water reabsorbed at equal ratios?

    <p>PCT</p> Signup and view all the answers

    What is the tonicity of the urine after passing through the loop of Henle?

    <p>Hypertonic</p> Signup and view all the answers

    What is the primary function of aldosterone in the distal nephron?

    <p>Regulation of sodium reabsorption</p> Signup and view all the answers

    About what percentage of filtered sodium and chloride is reabsorbed in the early segment of the distal convoluted tubule?

    <p>10%</p> Signup and view all the answers

    What is the site of two important processes, one involving exchange of sodium for potassium and the other determining the final concentration of the urine?

    <p>Distal nephron</p> Signup and view all the answers

    What is a benefit of long-term use of nifedipine?

    <p>Reduced rates of overt heart failure, coronary angiography, and coronary bypass surgery</p> Signup and view all the answers

    What is a precaution to be taken when using hydralazine in older adults?

    <p>Monitor for orthostatic hypotension</p> Signup and view all the answers

    What is the primary mechanism of action of hydralazine?

    <p>Dilates arterioles, reducing peripheral resistance and blood pressure</p> Signup and view all the answers

    Why is hydralazine often used in combination with beta blockers?

    <p>To prevent reflex tachycardia</p> Signup and view all the answers

    What is a characteristic of heart failure?

    <p>Ventricular dysfunction, reduced cardiac output, and fluid accumulation</p> Signup and view all the answers

    What is an important aspect of patient education when using nifedipine?

    <p>Recording anginal episodes, blood pressure, and adverse effects</p> Signup and view all the answers

    What is the mechanism of action of Eplerenone?

    <p>Selective blockage of aldosterone receptors</p> Signup and view all the answers

    What is a potential adverse effect of Eplerenone?

    <p>Hyperkalemia</p> Signup and view all the answers

    What is a contraindication for the use of CCB?

    <p>Sick sinus syndrome</p> Signup and view all the answers

    What is the primary indication for the use of CCBs?

    <p>Hypertension and angina pectoris</p> Signup and view all the answers

    What is a characteristic of Verapamil?

    <p>It can be used in infants</p> Signup and view all the answers

    What is a common adverse effect of CCBs in older adults?

    <p>All of the above</p> Signup and view all the answers

    What is a consideration when choosing between Verapamil and Diltiazem?

    <p>Type of arrhythmia</p> Signup and view all the answers

    What is the primary effect of CCBs on the heart?

    <p>Reduced contractile force</p> Signup and view all the answers

    What is the primary effect of digoxin on the heart?

    <p>It increases myocardial contraction force</p> Signup and view all the answers

    What is a potential complication of left-sided heart failure?

    <p>Pulmonary edema</p> Signup and view all the answers

    What is a sign of right-sided heart failure?

    <p>Liver congestion</p> Signup and view all the answers

    What is a common adverse effect of digoxin that can increase the risk of dysrhythmia?

    <p>Hypokalemia</p> Signup and view all the answers

    What is a lifestyle change that can help manage heart failure?

    <p>Exercising regularly</p> Signup and view all the answers

    What type of heart failure occurs when the left ventricle cannot relax properly?

    <p>Heart failure with preserved ejection fraction (HFpEF)</p> Signup and view all the answers

    What is the goal of statin therapy in heart failure management?

    <p>To reduce the risk of cardiovascular events</p> Signup and view all the answers

    What is a common medication class used to treat heart failure?

    <p>All of the above</p> Signup and view all the answers

    What is the primary reason why nifedipine is not used to treat dysrhythmias?

    <p>It lacks direct cardio suppressant actions</p> Signup and view all the answers

    What is the primary effect of nifedipine on the heart rate and contractile force?

    <p>Increased heart rate and contractile force</p> Signup and view all the answers

    Why is the slow-release (SR) formulation of nifedipine preferred over the immediate-release (IR) formulation?

    <p>It is less likely to cause reflex tachycardia</p> Signup and view all the answers

    What is the primary mechanism by which nifedipine activates the baroreceptor reflex?

    <p>Rapid fall in blood pressure</p> Signup and view all the answers

    What is the primary reason why beta blockers are often combined with nifedipine?

    <p>To reduce the risk of reflex tachycardia</p> Signup and view all the answers

    What is the primary difference between the effects of nifedipine's immediate-release (IR) and slow-release (SR) formulations on the baroreceptor reflex?

    <p>The IR formulation is more likely to cause reflex tachycardia, while the SR formulation is not</p> Signup and view all the answers

    What is the primary advantage of using nifedipine over verapamil or cardizem?

    <p>It is less likely to cause cardiac suppression</p> Signup and view all the answers

    What is the primary reason why nifedipine is used to treat hypertension and angina?

    <p>It is a potent vasodilator</p> Signup and view all the answers

    Study Notes

    Hemodynamics and Diuretics

    • Review of the circulatory system and cardiac output regulation
    • Diuretics:
      • Sites of action:
        • PCT (proximal convoluted tubule): reabsorbs 65% of filtered sodium and chloride, and all of the bicarbonate and potassium in the filtrate
        • Loop of Henle: decreases the volume of the tubular urine and causes the urine to become concentrated
        • Early segment of distal convoluted tubule: reabsorbs 10% of filtered sodium and chloride
        • Distal nephron: site of sodium-potassium exchange and regulation of final urine concentration
    • Triamterene/Dyrenium:
      • Non-aldosterone antagonist, potassium-sparing diuretic
      • Disrupts Na-K exchange in the distal nephron, decreasing Na reabsorption and reducing K secretion
      • Minimal diuresis
    • Indications and uses of diuretics:
      • Furosemide: rapid or massive mobilization of fluid, pulmonary edema, heart failure, hypertension
      • Thiazide: hypertension, edema, CHF, hepatic or renal disease
      • Spironolactone: hypertension, edema, CHF, counteracts K-wasting diuretics, off-label uses
      • Triamterene: hypertension, edema, combination with furosemide to counteract K-wasting effects
    • Factors to consider when choosing a diuretic:
      • Renal function
      • Indications and contraindications
      • Potential side effects
    • Adverse effects of diuretics:
      • Furosemide: K wasting, hyponatremia, hypochloremia, dehydration, hypotension
      • Thiazide: hyponatremia, hypochloremia, dehydration, hypotension, hyperglycemia, hyperuricemia
      • Spironolactone: shown to cause tumors in rats, avoid unnecessary use

    Vasodilators

    • Hydralazine:
      • MOA: dilates arterioles, decreases peripheral resistance, and lowers arterial BP
      • Uses: hypertension crisis, heart failure, reduces afterload for a short time in CHF
      • Can be used in infants 1 month
      • Requires combination with beta blockers to prevent reflex tachycardia
      • Contraindicated in CAD, high risk for falls in older adults

    Heart Failure

    • Review of pathophysiology and stages of HF:
      • Ventricular dysfunction, reduced CO, insufficient tissue perfusion, fluid accumulation
      • Tx: diuretics, RAAS inhibitors, beta blockers, digoxin
    • Stages of HF:
      • Systolic HF (HFrEF): LV dysfunction, reduced EF
      • Diastolic HF (HFpEF): LV can't relax, muscle is stiff
    • Left and right heart failure:
      • Left: LV pumps inefficiently, blood backs up into the lungs, pulmonary edema
      • Right: RV pumps inefficiently, blood backs up into the venous system, liver congestion, ascites, edema in legs

    Digoxin

    • MOA: (+) inotropic action, increases myocardial contraction force, increases CO, alters electric activity of the heart
    • Uses: treats CHF and dysrhythmias, 2nd line agent
    • Adverse effects and contraindications:
      • Digoxin-induced dysrhythmias, narrow therapeutic window, hypokalemia
    • Dosing and administration:
      • Hold for HR 100 despite max statins

    Lifestyle Changes

    • Eat better, move more, stop smoking, healthy BMI, manage stress

    Statins

    • Who needs to take a statin?
    • Teach patients about statins:

    Type 2 Diabetes

    • Pharmacologic approach:
      • Guided by person-centered tx factors (comorbidities, tx goals, social determinants of health, lifestyle)
      • ACE inhibitor or ARB to reduce risk of diabetic nephropathy and manage diabetic hypertension
      • Metformin or combination therapy
      • Early intro of insulin if necessary
      • Glucagon-like peptide 1 receptor agonist preferred to insulin when possible
    • A1C target goal for older adults: individualized, beware of overtreatment and polypharmacy
    • Older adults at risk for:
      • Overtreatment and polypharmacy
      • Hypoglycemia
      • Management should be personalized to reduce hypoglycemia risk

    Sodium-Potassium Exchange

    • Aldosterone, the principal mineralocorticoid of the adrenal cortex, stimulates reabsorption of sodium from the distal nephron and causes potassium to be secreted.
    • This can be viewed as an exchange mechanism, promoting sodium-potassium exchange by stimulating cells of the distal nephron to synthesize more pumps responsible for sodium and potassium transport.

    Diuretics

    Furosemide (Loop Diuretic)

    • Acts in the thick segment of the ascending limb of the loop of Henle, blocking reabsorption of Na and Cl, preventing reabsorption of water, which equals profound diuresis even when renal blood flow and GFR are low.
    • Can be combined with a thiazide diuretic (no use in combining with any other loop diuretic).
    • Indicated for use when rapid or massive mobilization of fluid is required, such as pulmonary edema associated with CHF, edema from heart, liver, or kidney that haven’t responded to other drugs, and/or HTN.

    Hydrochlorothiazide/Microzide (Thiazide Diuretic)

    • Promotes urine production by blocking reabsorption of Na and Cl in the early segment of the distal convoluted tubule, resulting in water retention in the nephron and increased flow of urine.
    • Indicated for use in HTN, edema in CHF, hepatic, or renal disease.

    Spironolactone/Aldactone (Aldosterone Antagonist, Potassium-Sparing Diuretic)

    • Blocks the action of aldosterone in the distal nephron, resulting in retention of K and excretion of Na.
    • Diuresis is scanty because most Na has already been reabsorbed before reaching the distal tubule.
    • Indicated for use in HTN, edema, CHF (blocking aldosterone creates protective effects), counteracts K-wasting diuretics, off-label: acne, hair loss, hirsutism, hormone therapy for transgender females.

    Triamterene/Dyrenium (Non-Aldosterone Antagonist, Potassium-Sparing Diuretic)

    • Disrupts Na-K exchange in the distal nephron by direct inhibition, resulting in decreased Na reabsorption and reduced K secretion, and increased Na excretion and K conservation.
    • Minimal diuresis.
    • Indicated for use in HTN, edema, combo drug can augment Lasix and counteract K-wasting effects.

    Factors to Consider When Choosing a Diuretic

    • Renal function: Furosemide can cause more loss of fluid and electrolytes than any other diuretic, K wasting, do not give if K is low.
    • Thiazide: MUST have an adequate kidney function to work (minimum 20-30mL/min), CI with digoxin, lithium, and other HTN meds.
    • Patient age: Furosemide use in caution in pts over 65 who are at higher risk for hyponatremia.

    Adverse Effects of Diuretics

    • ALL diuretics can cause profound diuresis with fluid and electrolyte depletion.
    • Loop & thiazide AE: hyponatremia, hypochloremia, dehydration, hypotension, hypokalemia, ototoxicity (loop), hyperglycemia, hyperuricemia, reduced HDL, increased LDL.
    • Spironolactone BBW: shown to cause tumors in rats, avoid unnecessary use.

    Two-Drug Combinations for BP Control

    • ACEI plus a thiazide diuretic, an ACEI plus a CCB, or a β blocker plus a thiazide.
    • Review comorbid conditions that influence a prescriber’s choice of antihypertensive medication.

    Comorbid Conditions and Antihypertensive Medication

    • HTN & CKD: ACE inhibitor + loop diuretic (avoid thiazide and potassium-sparing drugs; ineffective), if intolerant to ACE, do ARB.
    • HTN & DM: ACE inhibitors, ARBs, Ca Channel blockers (CCBs) are preferred.
    • ACEIs & ARBs can slow progression of renal damage and reduce albuminuria.
    • β blockers can mask sings of hypoglycemia.
    • Thiazide & loop diuretics can cause hyperglycemia.

    RAAS Drugs

    ACEIs

    • Blocks the conversion of angiotensin I to II, resulting in vasodilation, decreased blood volume, and cardiac remodeling, potassium retention, and fetal injury can occur.
    • Increase levels of bradykinin through the inhibition of Kinase II, which also results in vasodilation, COUGH, and rarely angioedema.

    ARBs

    • Compare and contrast ACE-I and ARB: differences in MOA, similarities, and when to prescribe one over the other.
    • MOA: blocks the effects of angiotensin II on BP, but does not affect kinin metabolism or bradykinin levels.

    Direct Renin Inhibitor

    • Eplerenone (Inspra): Potassium-sparing aldosterone antagonist (25 & 50 mg).
    • MOA: selective blockage of aldosterone receptors without blocking receptors for other steroid hormones; promotes retention of potassium and increased secretion of Na and water, resulting in reduced blood volume and BP.
    • USE: HTN & HF after tx with ACEI and BBs.
    • AE: has less AE than spironolactone because it’s more selective, hyperkalemia.

    CCB

    • MOA: prevents calcium ions from entering cells, resulting in vasodilation and decreased heart contractility and rate.
    • USE: Tx HTN, angina pectoris, cardiac arrhythmias.
    • CI: hypotension, sick sinus syndrome, 2nd or 3rd degree HB, grapefruit juice, can intensify effects of beta blockers.
    • AE: eczematous rash in older adults, dizziness, flushing, HA, edema of ankles & feet, worsening of HB.

    Vasodilators

    Hydralazine

    • MOA: dilates arterioles, resulting in decreased peripheral resistance and lowered arterial BP.
    • USE: HTN crisis, HF (reduces afterload for a short time in CHF).
    • Can be used in infants 1 month.
    • CI: CAD → angina attacks.
    • High risk for falls in older adults (polypharmacy & orthostatic hypotension).

    Cardiovascular I: Hemodynamics and Diuretics

    • The circulatory system and cardiac output regulation are reviewed
    • Diuretics work in the kidney, with different sites of action:
      • PCT (Proximal Convoluting Tubule): High resorptive capacity, reabsorbs 65% of filtered sodium and chloride, and all bicarbonate and potassium
      • Loop of Henle: Descending limb is freely permeable to water, decreases tubular urine volume and increases tonicity
      • Early segment of distal convoluted tubule: Reabsorbs 10% of filtered sodium and chloride, with water following passively
      • Distal nephron: Site of sodium-potassium exchange (under aldosterone influence) and final urine concentration (regulated by ADH)

    Eplerenone (Inspra)

    • MOA: Selective blockage of aldosterone receptors, promoting potassium retention and increased sodium and water secretion
    • USE: Hypertension and Heart Failure, especially in patients already on ACEI and BBs
    • AE: Hyperkalemia, with symptoms including dizziness, confusion, abnormal HR, numbness, and tingling
    • CI: Potassium supplements, impaired renal function, and DM II with microalbuminuria

    Calcium Channel Blockers (CCB)

    • MOA: Prevent calcium ions from entering cells, leading to vasodilation and reduced heart contractile force
    • USE: Hypertension, angina pectoris, and cardiac arrhythmias
    • CI: Hypotension, sick sinus syndrome, 2nd or 3rd degree heart block, and grapefruit juice (which can intensify effects of beta blockers)
    • AE: Eczematous rash in older adults, dizziness, flushing, headache, and edema of ankles and feet

    Dihydropyridines (Nifedipine)

    • MOA: Similar to CCB, but with more selective action on vascular smooth muscle
    • USE: Hypertension and angina pectoris
    • AE: Reflex tachycardia, especially with immediate-release formulation
    • CI: CAD, as it can exacerbate angina attacks
    • Pt education: Record anginal episodes, BP, and AE

    Vasodilators (Hydralazine)

    • MOA: Dilates arterioles, decreasing peripheral resistance and lowering arterial BP
    • USE: Hypertension crisis and Heart Failure (reduces afterload for a short time in CHF)
    • CI: CAD, as it can exacerbate angina attacks
    • AE: High risk for falls in older adults due to polypharmacy and orthostatic hypotension
    • Requires combination with beta blockers to prevent reflex tachycardia

    Heart Failure (HF)

    • Pathophysiology: Ventricular dysfunction, reduced CO, and insufficient tissue perfusion, leading to fluid accumulation
    • Stages of HF:
      • Systolic HF (HFrEF): LV can't contract properly
      • Diastolic HF (HFpEF): LV can't relax, muscle is stiff
    • Tx: Diuretics, RAAS inhibitors, beta blockers, and digoxin
    • Left HF: Blood backs up into the lungs, leading to pulmonary edema and RHF
    • Right HF: Blood backs up into the venous system, leading to liver congestion, ascites, and edema in legs

    Digoxin

    • MOA: (+) Inotropic action, increasing myocardial contraction force, and altering eclectic activity of the heart
    • USE: CHF and dysrhythmias, but not a first-line agent
    • AE/CI: Digoxin-induced dysrhythmias, narrow therapeutic window, hypokalemia, and many interactions
    • S/S of toxicity: Nausea, vomiting, and ECG changes
    • Antidote: Digoxin immune fab (Digibind)

    Lifestyle Changes for HF Management

    • Eat better
    • Move more
    • Stop smoking
    • Healthy BMI
    • Manage stress

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    This quiz covers the cardiovascular system, cardiac output regulation, and diuretics, including their sites of action in the kidney.

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