Electrolyte-Altering Drugs

Loop Diuretics

• Unit Prototype + Generic: Furosemide (-) → most commonly used
  
  

• Lasix

Furosemide Class

• Class: Loop Diuretics

MOA Furosemide

•  Acts directly on the ascending limb of the Loop of Henle to prevent reabsorption of sodium and chloride → water will exit the body along with the sodium, forcing the diuresis of it ALL → possesses renal, cardiac, and metabolic effects: increases renal prostaglandins resulting in the dilation of blood vessels and reduced peripheral vascular resistance

1. Primary Action (Where and How it Works)

• Target Location: It acts directly on the ascending limb of the Loop of Henle (a specific filtering structure inside the kidneys).

• Blocking Reabsorption: Normally, this part of the kidney reabsorbs sodium and chloride back into the body. Furosemide blocks this action entirely, preventing the reabsorption of sodium and chloride.

2. The Water Effect (Diuresis)

• Water Follows Salt: Because sodium and chloride stay trapped inside the kidney tubules instead of being reabsorbed, water stays with them.

• Forcing Diuresis: Since water follows salt due to osmosis, the water is forced out of the body through heavy urine output (diuresis), flushing out massive amounts of sodium, chloride, and water.

3. Extra Systemic Effects (Renal, Cardiac, and Metabolic)

• Releasing Prostaglandins: Furosemide stimulates the kidneys to release renal prostaglandins.

• Dilating Blood Vessels: These prostaglandins cause the blood vessels to widen (dilation).

• Lowering Resistance: This widening reduces peripheral vascular resistance (the pressure the heart has to fight against to push blood through the body), which helps relieve strain on the heart and cardiovascular system.

Furosemide Use

• Use: Edema Associated with Hepatic Failure or hepatic/renal diseases or pulmonary edema, HTN, to increase renal excretion of calcium in patients with hypercalcemia, ascites

furosimide expected effects

• Expected Effects: Potent Diuresis and subsequent loss of fluids; decreased fluid volume leading to reductions in → BP (lowers blood volume, CO, SVR), Left Ventricular end-diastolic pressure, potassium and sodium reduction

Adverse Effects furosimide

Hyponatremia, hypocholermia, dehydration, hypotension - loss of volume and relaxation of venous smooth muscle, hypokalemia, ototoxicity - damage of ears: rining/tinnitus/hearing loss, hyperglycemia, hyperuricemia, Black Box: usage in pregnancy, increases concentration of lipids

Nursing Implications Furosemide

• Not the first-line HTN treatment. Can be administered orally or parenterally → PO onset is 45 mins, IV onset is 5 mins: ensure Foley is in and secure. Works extremely well and is most commonly chosen for those w/ renal failure

1. Drug Interactions: Otoxic drugs - ear-damaging drugs, Potassium-sparing drugs - too much K+ back and forth for the body: one excretes K+ and one spares K+, Anti-Hypertensive agents, NSAIDs - Ibuprofen (consistent use multiple times a day, not a one-dose issue) 

• Unit Prototype + Generic: Hydrochlorothiazide —

• (Esidrix, HydroDIURIL)

• Class: Hydrochlorothiazide

• Thiazide Diuretics

• MOA: Hydrochlorothiazide

1. Where It Works

• Target Location: It acts primarily in the distal convoluted tubule (a specific, further-down section of the kidney's filtering tubes). (Note: This tells us it is a Thiazide Diuretic, like Hydrochlorothiazide, which works further down the line than loop diuretics).

2. What It Does to Electrolytes

• Blocking Reabsorption: It stops the kidneys from reabsorbing sodium, chloride, and potassium back into the bloodstream.

• The Result: Because these ions stay trapped inside the kidney tubules, water follows them via osmosis, causing you to pee them out along with excess water (diuresis).

3. What It Does to Blood Vessels

• Direct Relaxation: It directly relaxes and dilates the small blood vessels (arterioles).

• The Benefit: By widening these blood vessels, it lowers the resistance the heart has to push against, which helps reduce and manage high blood pressure.

• Use: Hydrochlorothiazide

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• HTN, Edematous states, Idiopathic hypercalciuria, Diabetes Insipidus, HF, Adjunct drugs in treatment of edema related to HF, hepatic cirrhosis, or corticosteroid or estrogen therapy

• Expected Effects:Hydrochlorothiazide

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• Water, sodium, chloride, and potassium (to a lesser extent) are excreted; lowered peripheral vascular resistance; depleted sodium and water (and potassium)

• Adverse Effects: :Hydrochlorothiazide

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• Elevate uric acid and glucose, Hyponatremia, Hypochloremia, dehydration, hypokalemia, Black Box: Pregnancy and Lactation, impact on lipids/calcium/magnesium levels (inc. conc.) → Risk of all of these effects is LESS than with loop diuretics, which have a decreased risk of adverse effects

• Nursing Implications: Hydrochlorothiazide

• Causes excess diuresis but is not as potent as loop diuretics. Most should not be used if creatinine clearance is less than 30-50 mL/min (normal is 125 mL/min), Oral only and commonly used in combo w/ other loop diuretics; not effective when urine flow is scant (Ex those in renal failure), unlike loop, which can still be used 

• Unit Prototype + Generic: Spironolactone —, also known as —

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• (Aldactone), aldosterone-inhibiting diuretics!

• Class:Spironolactone

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• Potassium-Sparing Diuretics

MOA Spironolactone

• Where it works: In the collecting ducts and distal convoluted tubule (the final filtering areas of the kidneys).

• Blocking Aldosterone: It competitively binds to aldosterone receptors, meaning it blocks aldosterone from attaching to its receptors.

• Stopping the Hormone: Normally, aldosterone tells the body to hold onto sodium and water while kicking potassium out into the urine. Spironolactone blocks that action, forcing the body to excrete (pee out) sodium and water instead.

• Saving Potassium: Because it interferes with the sodium-potassium exchange, it stops potassium from being pumped into the tubule, preventing potassium loss and keeping it in the body.

Use Spironolactone

• Hyperaldosteronism (retaining too much sodium and H2O), Hypertension, reversing potassium loss caused by potassium-losing drugs, Certain cases of hepatic failure

• Expected Effects: spirolactone

• Expected Effects: Prevent potassium from being pumped into the tubule → thus preventing its secretion; competitively block aldosterone receptors and inhibit their action → aldosterone normally causes sodium and water retention; if it is blocked, then sodium and water are excreted

adverse effects of spironolactone

• Adverse Effects: Gynecomastia (development of breast tissue in males), Amenorrhea (loss of menstrual cycles), Irregular menses (cycles may be irregular permanently), post-menopausal bleeding (spontaneously restarting period), Hyperkalemia

nursing implications of spironolactone

• Nursing Implications: Patients do not lose sodium; good for those w/decreased sodium