Pharmacology Diuretics Quiz

Diuretics

• Furosemide (loop diuretic) is used in patients with low GFR (renal impairment)
• Low potassium levels can increase the risk of heart arrhythmia when taking diuretics
• Patient education for furosemide includes:
  • Monitoring blood pressure
  • Watching for signs of postural hypotension
  • Eating potassium-rich foods
• Furosemide should not be prescribed with digoxin, NSAIDS, antihypertensive drugs, and lithium
• Loop diuretics work by inhibiting sodium and chloride reabsorption in the loop of Henle, leading to significant urine production
• Thiazide diuretics act on the distal convoluted tubule, inhibiting sodium reabsorption to a lesser extent, resulting in a moderate increase in urine output

Hydrochlorothiazide (Microzide)

• Not suitable for patients with inadequate renal function (GFR below 30)
• Diuresis starts in 2 hours and peaks in 4-6 hours
• Important to check BP, HR, weight, signs of hypokalemia, and signs of gout before prescribing

Spironolactone (Aldactone)

• Potassium-sparing diuretic
• Produces a modest increase in urine and a substantial decrease in potassium excretion
• Often used alongside other diuretics to counteract potassium loss
• Main reason for prescription is to counteract potassium loss caused by thiazide and loop diuretics
• Adverse effects include hyperkalemia, gynecomastia, menstrual irregularities, impotence, hirsutism, and deep voice
• May cause tumors in rats, so avoid unnecessary use

Triamterene (Dyrenium)

• Potassium-sparing diuretic
• Works by disrupting sodium and potassium exchange, resulting in decreased sodium absorption and reduced potassium secretion
• Should not be prescribed to patients with elevated potassium levels
• Adverse effects include hyperkalemia, nausea, vomiting, leg cramps, and dizziness
• Diuresis starts in a few hours

Hypertension

• Diuretics are the first-choice drug for treating hypertension in African Americans
• In African Americans, monotherapy with beta blockers and ACEIs is less effective
• ACEIs and beta blockers may be used in combination, especially in African Americans with type 1 diabetes with proteinuria or hypertensive nephrosclerosis
• Recommended combinations for hypertension include:
  • ACEI plus a thiazide diuretic
  • ACEI plus a calcium channel blocker (CCB)
  • Beta blocker plus a thiazide diuretic

Angiotensin-Converting Enzyme (ACE) Inhibitors

• Lisinopril is an ACEI
• ACEIs lower angiotensin II levels, dilate blood vessels, and reduce blood volume, leading to lower blood pressure
• Uses include hypertension, CHF, acute MI, left ventricular dysfunction, and nephropathy
• Contraindications include pregnancy and renal artery stenosis
• Baseline data needed before starting includes blood pressure and renal function
• Adverse effects include first-dose hypotension, hyperkalemia, cough, renal failure, angioedema, and neutropenia
• Fetal injury is a black box warning

Angiotensin II Receptor Blockers (ARBs)

• Losartan is an ARB
• ARBs block the actions of angiotensin II, reducing blood pressure
• Uses include hypertension, MI, diabetic nephropathy, and prevention of stroke and death
• Adverse effects are similar to ACEIs, but with a lower risk of cough and hyperkalemia
• Not recommended for use with ACEIs

Aldosterone Antagonists

• Eplerenone is a selective aldosterone antagonist
• MOA: Selective blockade of aldosterone receptors, promoting retention of potassium and increased secretion of sodium and water
• Recommended for adding to standard HF therapy in patients with persistent symptoms despite adequate treatment with ACEI and beta blocker
• Contraindications include use with potassium supplements, potassium-sparing diuretics, elevated potassium levels, and impaired renal function
• Important to monitor blood pressure, potassium levels, and GFR

Calcium Channel Blockers (CCBs)

• Diltiazem is a CCB
• Uses include angina, hypertension, and dysrhythmia (A-flutter, A-fib, PSVT)
• Baseline data needed before starting includes blood pressure, heart rate, liver function, and kidney function
• Adverse effects include dizziness, swelling of hands and feet, bradycardia, and exema-like rash in older adults

Direct Renin Inhibitors (DRIs)

• Aliskiren is a DRI
• MOA: Inhibits the conversion of angiotensinogen to angiotensin I
• Adverse effects include cough, hyperkalemia, and diarrhea
• Fetal injury is a black box warning

Vasodilators

• Hydralazine is a vasodilator
• MOA: Dilates arterioles and reduces peripheral resistance, reducing blood pressure
• Therapeutic goal: Reduce blood pressure and reduce afterload in CHF
• Adverse effects include reflex tachycardia, myocardial contractility, and NA and water retention
• Lupus-like syndrome can occur, with symptoms including muscle pain, joint pain, fever, nephritis, and pericarditis

Beta Blockers

• Metoprolol is a selective beta blocker (B1)
• Preferred for patients with lung issues
• Uses include angina, HF, hypertension, and MI
• Interactions: Use with caution in patients with diabetes, and monitor for hypoglycemia

Diabetes

• Metformin is the first-line medication for type 2 diabetes
• For patients with diabetes and hypertension, ACEI or ARB is the preferred medication
• For patients with diabetes and cardiovascular disease, kidney disease, or heart failure, sodium-glucose cotransporter 2 inhibitor or glucagon-like peptide 1 receptor agonist is recommended
• Target A1C level is below 7.0 for most patients, and below 8.0 for patients with severe hypoglycemia, limited life expectancy, or advanced micro- and macrovascular complications

Diuretics

• Furosemide (loop diuretic) is used in patients with low GFR (renal impairment).
• Low potassium levels can increase the risk of heart arrhythmia when taking diuretics.
• When prescribing Furosemide, patient education should include:
  • Monitoring blood pressure
  • Recognizing signs and symptoms of postural hypotension (e.g., standing slowly to avoid dizziness)
  • Eating potassium-rich foods (e.g., dried fruit, nuts, spinach, potatoes)
• Furosemide (Lasix) should not be prescribed with:
  • Digoxin (due to potassium loss causing dysrhythmia)
  • NSAIDS
  • Antihypertensive drugs
  • Lithium
• Loop diuretics (e.g., Furosemide) work by inhibiting sodium and chloride reabsorption in the loop of Henle, leading to a significant increase in urine production.
• Thiazide diuretics act on the distal convoluted tubule, inhibiting sodium reabsorption to a lesser extent, resulting in a moderate increase in urine output.

Hydrochlorothiazide (Microzide)

• Hydrochlorothiazide should not be prescribed in patients with inadequate renal functioning (GFR < 30).
• Diuresis starts in 2 hours and peaks in 4-6 hours with Hydrochlorothiazide.
• Important patient monitoring before prescribing Hydrochlorothiazide includes:
  • Blood pressure
  • Heart rate
  • Weight
  • Signs and symptoms of hypokalemia (e.g., constipation, heart palpitation, fatigue, muscle weakness, tingling)
  • Signs and symptoms of gout

Furosemide (Loop Diuretic)

• Furosemide has a higher risk of ototoxicity.
• Spironolactone (Aldactone) is a potassium-sparing diuretic.
• Spironolactone produces a modest increase in urine and a substantial decrease in potassium excretion.
• Spironolactone can be used alongside other diuretics to counteract potassium loss.

Spironolactone (Aldactone)

• Spironolactone is prescribed to counteract potassium loss caused by thiazide and loop diuretics.
• Adverse effects of Spironolactone include:
  • Hyperkalemia (which can cause dysrhythmia)
  • Gynecomastia
  • Menstrual irregularities
  • Impotence
  • Hirsutism
  • Deep voice
• Spironolactone is shown to cause tumors in rats, so it should be avoided unless necessary.
• Important baseline data needed before prescribing Spironolactone includes:
  • Weight
  • Vital signs
  • Electrolytes
  • Testosterone levels (if prescribed in transgender patients)

Triamterene (Dyrenium)

• Triamterene is a potassium-sparing diuretic.
• Triamterene works by disrupting the sodium and potassium exchange, resulting in decreased sodium absorption and reduced potassium secretion.
• Triamterene should not be prescribed in patients with elevated potassium levels.
• Diuresis starts in a few hours with Triamterene.

Lisinopril (Zestril): Angiotensin-Converting Enzyme Inhibitor

• Patient education when prescribing Lisinopril includes:
  • Educating about first-dose hypotension
  • Avoiding potassium supplements
  • Notifying the provider if cough or facial swelling develops
• Important patient monitoring before starting Lisinopril includes:
  • Blood pressure
  • Proteinuria
  • GFR rate
• Factors that increase the risk of cough while taking Lisinopril include:
  • Advanced age
  • Female sex
  • Asian ancestry
• The cough should decrease after 3 days and resolve within 10 days after stopping the medication.

Losartan (Cozar): Angiotensin II Receptor Blocker (ARB)

• Losartan is approved for hypertension, MI, diabetic nephropathy, and prevention of stroke and death in high-risk patients.
• Losartan differs from ACE inhibitors (e.g., Lisinopril) in that it blocks the actions of angiotensin II, whereas ACE inhibitors block the production of angiotensin II.
• The primary difference between Losartan and Lisinopril is that ARBs pose a lower risk of cough and hyperkalemia.

Digoxin (Lanoxin)

• Digoxin increases myocardial contractility and alters the electrical activity of the heart.
• Digoxin is used to treat dysrhythmia (A-fib or flutter) or CHF.
• Interactions of Digoxin include:
  • Hypokalemia, which increases the risk of dysrhythmia
  • Avoid use in V-fib or V-tach
• Important patient monitoring while prescribing Digoxin includes:
  • Digoxin levels (narrow therapeutic window: 0.5-0.8)
  • Apical pulse
  • Assessing for decreased signs and symptoms of CHF
• Patient education when prescribing Digoxin includes:
  • Monitoring heart rate
  • Holding the medication if heart rate is below 50
  • Recognizing signs of toxicity (e.g., altered heart rate or rhythm, visual or gastrointestinal disturbances)

Metoprolol (Lopressor)

• Metoprolol is a selective beta-1 (B1) adrenergic blocker.
• Metoprolol is preferred for patients with lung issues because it only affects the heart, not the lungs.
• Metoprolol is used to treat angina, HF, HTN, and MI.
• Metoprolol is the preferred medication for African Americans.

Diabetes Management

• For patients with diabetes and hypertension, ACE inhibitors (e.g., Lisinopril) or ARBs (e.g., Losartan) are preferred.
• For patients with diabetes and cardiovascular disease, kidney disease, or heart failure, sodium-glucose cotransporter 2 inhibitors and/or glucagon-like peptide 1 receptor agonists are preferred.
• The target A1C level for most patients with diabetes is < 7.0.
• For patients with severe hypoglycemia, the target A1C level is < 8.0.
• The first-line medication for youth with new-onset diabetes is metformin.
• Youth with A1C > 8.5% and acidosis should be managed with insulin and IV fluids until acidosis resolves.