Patho/Pharm II - Chapter 44: Diuretics

Thiazide diuretics

-Also known as benzothiadiazides -Effects are similar to those of loop diuretics --Increase renal excretion of sodium, chloride, potassium, and water --Elevate levels of uric acid and glucose -First line for treating hypertension -Maximum diuresis is considerably lower than with loop diuretics -Not effective when urine flow is scant

Spironolactone (Aldactone)

-Blocks aldosterone in the distal nephron, retains potassium, and increases sodium excretion -Used for... --Hypertension --Edematous states --Heart failure (decreases mortality when severe) --Primary hyperaldosteronism --Premenstrual syndrome -Polycystic ovarian syndrome --Acne in young women

diuretics

-Blocks sodium and chloride reabsorption, causing fluid loss --Loss of chloride may also cause contraction alkalosis -Site of action is proximal tubule (promotes greatest diuresis) -Adverse effects include hypovolemia, acid-base imbalance, and electrolyte imbalances --Potassium imbalance is most common

Amiloride (Midamor)

-Blocks sodium-potassium exchange in the distal nephron -Counteracts potassium loss caused by more powerful diuretics -Adverse effect is hyperkalemia -Interacts with ACE inhibitors and other drugs that may cause hyperkalemia

Potassium sparing diuretics

-Causes a modest increase in urine production with a substantial decrease in potassium excretion -Used for congestive heart failure, systolic heart failure with an ejection fraction <30%, hypertension, acne, PCOS, and hair loss -Rarely used alone for therapy -Aldosterone antagonist is spironolactone -Nonaldosterone antagonists are triamterene and amiloride

hydrochlorothiazide drug interactions

-Digoxin -Augments effects of hypertensive medications -Can reduce renal excretion of lithium (leading to accumulation) -NSAIDs may blunt diuretic effect -Can be combined with ototoxic agents without increased risk of hearing loss

furosemide drug interactions

-Digoxin (hypokalemia) -Ototoxic drugs -Potassium-sparing diuretics (offsets hypokalemia) -Lithium (affects sodium levels) -Antihypertensive agents -Nonsteroidal anti-inflammatory drugs (cause decrease in effectiveness of diuretic)

Triamterene (Dyrenium)

-Disrupts sodium-potassium exchange in the distal nephron -Direct inhibitor of the exchange mechanism -Decreases sodium reuptake -Inhibits ion transport -Used therapeutically for hypertension and edema

adverse effects of mannitol

-Edema -Headache -Nausea -Vomiting -Fluid and electrolyte imbalance

high-ceiling (loop) diuretics

-Furosemide (Lasix) (most popular) -Ethacrynic acid (Edecrin) -Bumetanide (Bumex) -Torsemide (Demadex)

loop diuretics

-Furosemide (Lasix) is most frequently prescribed -Acts on ascending loop of Henle to block reabsorption -Has a rapid onset (oral: 60 min, IV: 5 min) -Must push slowly (10 mg/min); if pushed too quickly, the patient may sustain inner ear damage -Used for pulmonary edema, edematous states, and hypertension

adverse effects of spironolactone

-Hyperkalemia -Benign and malignant tumors -Endocrine effects -May feminize men and masculinize women

adverse effects of triamterene

-Hyperkalemia -Leg cramps -Nausea -Vomiting -Dizziness -Blood dyscrasias (rare)

adverse effects of hydrochlorothiazide

-Hyponatremia, hypochloremia, and dehydration -Hypokalemia -May cause fetal death in pregnancy -Hyperglycemia -Hyperuricemia -Hypocalcemia and hypomagnesemia

adverse effects of furosemide

-Hyponatremia, hypochloremia, and dehydration -Hypotension, due to loss of volume and relaxation of venous smooth muscle --Blood pressure must be monitored -Hypokalemia -Ototoxicity -Nephrotoxicity -Hyperglycemia -Hyperuricemia -Fetal loss during pregnancy -Hypocalcemia and hypomagnesemia

categories of diuretics

-Loop (furosemide) -Thiazide (hydrochlorothiazide) -Osmotic (mannitol) -Potassium-sparing --Aldosterone antagonists (spironolactone) --Nonaldosterone antagonists (triamterene) -Carbonic anhydrase inhibitors (seen in ophthalmology)

Hydrochlorothiazide (HydroDIURIL)

-Most widely used -Mechanism of action is located in early segment distal convoluted tubule, right after loop of Henle -Peaks in 4-6 hours -Used for essential hypertension, edema, and diabetes insipidus

adverse effects of loop diuretics

-Ototoxicity -Hypovolemia -Hypotension -Hypokalemia -Hyperuricemia -Hyperglycemia -Disruption of lipid metabolism

Mannitol (Osmitrol)

-Promotes diuresis by creating osmotic force within the lumen of the nephron, pulling water out of the interstitium and tissues --May result in peripheral edema -Drug must be given parenterally -Used therapeutically for... --Prophylaxis of renal failure --Reduction of intracranial and intraocular pressure

spironolactone drug interactions

-Thiazide and loop diuretics --Offsets K+ loss to prevent cardiac dysrhythmias via aldosterone blockers -Agents that raise potassium levels

C.) Salt substitutes

A patient is prescribed spironolactone [Aldactone] for treatment of hypertension. Which foods should the nurse teach the patient to avoid? A.) Baked fish B.) Low-fat milk C.) Salt substitutes D.) Green beans

Mannitol, osmotic force draws edematous fluid from brain into blood

A patient who sustained a head injury is admitted to the critical care unit with increased intracranial pressure (ICP). The healthcare provider says that a diuretic will be used to lower the patient's ICP. The nurse anticipates that which diuretic will be ordered, and why?

Use a filter needle when withdrawing from vial, as well as an in-line filter for IV infusion (prevents crystals from entering circulation)

Are there any other steps the nurse should take regarding IV administration of mannitol?

B.) Gentamicin [Garamycin]

A patient with heart failure who takes furosemide [Lasix] is diagnosed with bacterial pneumonia. Which medication, if ordered by the physician, should the nurse question? A.) Ciprofloxacin [Cipro] B.) Gentamicin [Garamycin] C.) Amoxicillin [Amoxcil] D.) Erythromycin [E-Mycin]

oral, parenteral

Furosemide comes in _______ and __________ preparations

oral

IV/Oral loop diuretics last longer, but have a slower onset

Warm it and then cool to body temperature

Mannitol IV has been ordered for the patient. When the IV solution of mannitol arrives from the pharmacy, the nurse notes crystals in the fluid. What is the most appropriate action by the nurse?

-one

Most aldosterone blockers end in ______ (but all this really indicates is that it is a hormone-based drug)

-ide

Most loop diuretics end in...?

2

Oral diuretics should not be given past _____ pm, or nocturia may occur

D.) Schedule the medication to be given at 0800 and 1400.

The nurse cares for a patient who is prescribed oral bumetanide twice daily. It is most important for the nurse to take which action? A.) Monitor the patient for signs and symptoms of hyperkalemia. B.) Insert a urinary catheter and assess the hourly urine output. C.) Weigh the patient before administering each dose. D.) Schedule the medication to be given at 0800 and 1400.

True

True or False: Loop diuretics are not sulfa-based

esophageal varices

Use of potassium-sparing diuretics may result in the formation of _________ _________; if ruptured, these can cause death by bleeding out Aldosterone blockers lower portal pressure and prevent rupture

beta blocker, ACE inhibitor, and ARB/Entresto

What is the standard therapy for heart failure patients?

A.) Oranges, spinach, and potatoes

When providing discharge teaching for a patient who has been prescribed furosemide [Lasix], it is most important for the nurse to include which dietary items to prevent adverse effects of furosemide [Lasix] therapy? A.) Oranges, spinach, and potatoes B.) Baked fish, chicken, and cauliflower C.) Tomato juice, skim milk, and cottage cheese D.) Oatmeal, cabbage, and bran flakes