Pharmacology Ch.43-Diuretics

What are side effects of loop diuretics?

**Thrombocytopenia** **Thiamine deficiency** Fluid and electrolyte imbalances Hypochloremic metabolic alkalosis Orthostatic hypotension Skin disturbances Transient deafness

Thiazides and thiazide-like diuretics

*Act on the distal convoluted renal tube , beyond the loop of Henle, to promote sodium, chloride, and water excretion. *Used to treat htn and peripheral edema. *Not effective for immediate diuresis and should not be used to promote fluid loss in pt with severe renal dysfunction. Creatinine >30 mL/min decreases effectiveness of thiazide diuretic. *Cause a loss of sodium,potassium, and magnesium, but promotes calcium reabsorption. Monitor for Hypokalemia, Hypomagnesemia,Hypercalcemia,Hypochloremia, Hyperuricemia,Hyperglycemia,Hyperlipidemia

Loop (High-ceiling) diuretics

*Act on thick ascending loop of Henle to inhibit chloride transport of sodium into the circulation (inhibit passive reabsorption of sodium). *sodium and water are lost, along with potassium, calcium and magnesium. Blood sugar and uric acid levels can be affected. *Extremely potent, cause marked depletion of water and electrolytes. This high diuretic potential is why they are called high-ceiling diuretics or potassium-wasting. *More potent than thiazides for promoting diuresis, less effective as antihypertensive agents *Should not be prescribed if a thiazide could alleviate body fluid excess. *Compete for protein-binding sites with other highly protein-bound drugs. (ex:warfarin)

Spironolactone (Aldactone)

*Aldosterone antagonist, was first potassium sparing diuretic. *Blocks action of aldosterone and inhibits sodium potassium pump (potassium is retained, sodium is excreted) *Has been prescribed for pts with cardiac disorders because of potassium-retaining effect. Heart rate is more regular, possibility of myocardial fibrosis is decreased. *Effects may take up to 48 hrs. Side effects: n/v/d, rash, dizziness, headache, weakness, dry mouth, photosensitivity *Hyperkalemia if given with ACE inhibitor, increases effects of antihypertenisives and lithium *Administer in morning to avoid nocturia, take with or after meals to avoid nausea

Potassium-sparing diuretics examples

*Amiloride (Midamor): for diuretic-induced hypokalemia, HTN, HF, cirrhosis of liver *Eplerenone (Inspra): for htn, chronic HF post MI, also classified as selective aldosterone receptor blocker. *Spironolactone (Aldactone) *amiloride HCL and HCTZ (Moduretic): combinations contain potassium-wasting and potassium-sparing diuretics. Controls htn and edema. Used to prevent occurrence of hypokalemia. sprionolactone and HCTZ (Aldactazide): same as Moduretic Triamterene and HCTZ (Dyazide, Maxzide): Same as Moduretic

Carbonic Andhydrase Inhibitors

*Block action of enzyme carbonic anhydrase, which is needed to maintain the body's acid-base balance (hydrogen and bicarbonate ion balance). Inhibition of this enzyme causes increased sodium, potassium, and bicarbonate excretion. *With prolonged use metabolic acidosis can occur. *Used to decrease IOP in pts with chronic glaucoma, diuresis, management of epilepsy, treatment of high-altitude or acute mountain sickness, pt in metabolic alkalosis who needs diuretic. *May be altered with loop diuretic

Furosemide (Lasix)

*Frequently prescribed for pts who creatinine clearance is less than 30 mL/min and for those with end-stage renal disease. *Used to treat fluid retention/overload caused by HF, renal dysfunction, cirrhosis, htn, acute pulmonary edema *Causes excretion of calcium, unlike thiazides, which inhibit calcium loss. *If Lasix is not effective in removing body fluid, a thiazide may be added, but Lasix should never be added with another loop diuretic. *More potent diuretic than thiazides, causes a vasodilatory effect, thus renal flow increases before diuresis. *Used when sodium restriction and use of less potent diuretics fail. Oral dose is 2x that of IV dose. Onset is 30-60 mins, IV is 5 mins. *Side effects: n/d, electrolyte imbalances, vertigo, abd cramping, constipation, rash, headache, weakness, ECG changes, blurred vision, muscle cramping

Osmotic Diuretics

*Increase osmolality (concentration) and sodium reabsorption in proximal tubule and loop of Henle. *Sodium, chloride, potassium (to a lesser degree), and water are excreted. *Used to prevent kidney failure, decrease ICP, decrease IOP. Ex:Mannitol

Short-acting thiazides

chlorothiazide (Diuril), hydrochlorothiazide (Esidrix, HCTZ) *For htn and peripheral edema. Diuril may be given by IV for adults

NCLEX review questions

p.632

Osmotic diuretic-Mannitol

*Potent osmotic potassium-wasting diuretic frequently used in emergency situations such as ICP and IOP. *Can be used with cisplatin and carboplatin in cancer chemotherapy to induce a frank diuresis and decreased side effects of treatment. *Most frequently prescribed osmotic, followed by urea. *Diuresis occurs within 1-3 hrs after IV administration *Side effects: fluid/electrolyte imbalance, pulmonary edema from rapid shift of fluids, n/v, tachycardia, acidosis *vial should be warmed to dissolve crystals-do not give if crystals are present and haven't been dissolved. *Must be given in extreme caution to pts with heart disease or HF. Immediately discontinue if pt develops HF or renal failure.

Potassium-sparing Diuretics

*Weaker than thiazides and loop diuretics *Act primarily in collect duct renal tubules and late distal tubule to promote sodium and water excretion and potassium retention. Drugs interfere with sodium-potassium pump controlled by aldosterone. *Used as mild diuretics or in combination with another diuretic (HCTZ, antihypertensive) *Continuous use of potassium-wasting requires daily oral potassium supplement because the kidney excrete potassium, sodium, and body water. HOWEVER, potassium supplement is not used if pt takes potassium-sparing. *If potassium level is greater than 5.3 mEq/L, d/c potassium-sparing diuretic and restrict high potassium foods.

Carbonic Andhydrase Inhibitors examples

*acetazolamide (Diamox): for edema, treating absence (petit mal) seizures, open-angle glaucoma. *May cause fluid/electrolyte imbalance, metabolic acidosis, n/v, anorexia, confusion, orthostatic hypotension, crystalluria, hemolytic anemia, and renal calculi. *methazolamide (Neptazane): similar to dichlorphenamide

Thiazide-like diuretics

*chlorthalidone (Hygroton, Thalitone)-For htn and edema associated with HF and renal or liver dysfunction. Very long duration of action (24-72 hrs) *indapamide- for htn and edema. Long actin. May be classified as loop diuretic *Metolasone (Zaroxolyn)-for htn and edema. Intermediate-acting diuretic, more effective than thiazides in pts with decreased renal function

Powerpoint Questions

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What are the three groups that thiazides are divided into?

1. Short-acting (duration less than 12 hrs) 2. intermediate-acting (duration 12-24 hrs) 3. long-acting (duration more than 24 hrs)

What are the five categories of diuretics that are effective in removing water and sodium?

1. Thiazide and thiazide-like 2. Loop or high-ceiling 3. Osmotic 4. Carbonic anhydrase inhibitor 5. Potassium-sparing *Thiazide, loop, and potassium-sparing are the most frequently prescribed for htn and edema associated with HF. Except for those in the potassium-sparing group, all diuretics are potassium-wasting.

What does the nurse know to be correct concerning the use of mannitol (Osmitrol) in patients? A.Decreases intracranial pressure B.Increases intraocular pressure C.Causes sodium and potassium retention D.Causes diuresis in several day.

A.Decreases intracranial pressure

Figure 43-1 p. 621

Affecting proximal tubule: Osmotic, mercurial, and carbonic anhyrdrase inhibitor Loop of Henle: Loop diuretics Distal tubule: thiazides Collecting tubule: potassium-sparing

The nurse knows that which statement is correct regarding nursing care of a patient receiving hydrochlorothiazide (HCTZ)? Select all that supply. A. Monitor patient for signs of hypoglycemia. B.Administer ordered potassium supplements C.Monitor serum potassium and uric acid levels D.Assess blood pressure before administration E.Notify health care provider if patient has had oliguria for 24 hours. F.Assess for decreased cholesterol and triglyceride levels

B.Administer ordered potassium supplements C.Monitor serum potassium and uric acid levels D.Assess blood pressure before administration E.Notify health care provider if patient has had oliguria for 24 hours.

What should the nurse do when a patient is taking furosemide (Lasix)? A.Instruct patient to change positions quickly when getting out of bed B.Assess blood pressure before administration C.Administer at bedtime for maximum effectiveness D.Teach to avoid fruits to prevent hyperkalemia

B.Assess blood pressure before administration

The patient has been receiving sprionolactone (Aldactone) 50 mg/day for heart failure. The nurse should closely monitor the patient for which condition? A.Hypokalemia B.Hyperkalemia C.Hypoglycemia D.Hypermagnesemia

B.Hyperkalemia

A patient is taking hydochlorothiazide (HCTZ) 50 mg/day and digoxin (Lanoxin) 0.25 mg/day. The nurse plans to monitor the patient for which potential electrolyte imbalance? A. Hypocalcemia B.Hypokalemia C.Hyperkalemia D.Hypermagnesemia

B.Hypokalemia

A patient has heart failure, and a high dose of furosemide (Lasix) is ordered. What suggests a favorable response to Lasix? A.Decrease in level of consciousness and sleeping more B.Respiratory rate decreases from 28/min to 20/min and the depth increases C.Increased congestion heard in breath sounds and complains of shortness of breath D.Urine output of 50 mL/4 h and intake of 200 mL.

B.Respiratory rate decreases from 28/min to 20/min and the depth increases

For the patient taking a diuretic, a combination such as triamterene and hydrochlorothiazide may be prescribed. The nurse realizes that this combination is ordered for which purpose? A.To decrease serum potassium level B.To increase serum potassium level C.To decrease glucose level D.To increase glucose level

B.To increase serum potassium level

A patient is receiving furosemide (Lasix). It is most important for the nurse to monitor the patient for the development of A.hyperkalemia. B.hypokalemia. C.hyponatremia. D.hypernatremia.

B.hypokalemia. *Hypokalemia is the most common electrolyte balance associated with furosemide (Lasix) therapy

Which statement about aldosterone does the nurse identify as being true? Aldosterone A.promotes sodium excretion. B.is a mineralocorticoid hormone. C.promotes potassium retention. D.is secreted by the pancreas.

B.is a mineralocorticoid hormone. *Aldosterone is a mineralocorticoid hormone that promotes sodium retention, and potassium excretion is not secreted by the pancreas.

A patient is admitted to the intensive care unit with increased intracranial pressure. The nurse would anticipate administering A.furosemide (Lasix). B.mannitol (Osmitrol). C.triamterene (Dyrenium). D.spironolactone (Aldactone).

B.mannitol (Osmitrol). *Osmotic diuretics such as mannitol (Osmitrol) increase the osmolality and sodium reabsorption in the proximal tubule and loop of Henle. Sodium, chloride, potassium, and water are excreted. This group of drugs is used to prevent kidney failure, to decrease intracranial pressure, and to decrease intraocular pressure. Mannitol is a potent osmotic potassium-wasting diuretic frequently used in emergency situations such as ICP and IOP.

Before administering triamterene (Dyrenium), it is most important for the nurse to determine if the patient is also receiving A.digoxin (Lanoxin). B.potassium chloride (K-Dur). C.acetaminophen (Tylenol). D.doxazosin (Cardura).

B.potassium chloride (K-Dur). *Triamterene (Dyrenium) is a potassium-sparing diuretic. Potassium supplementation is not indicated unless the patient's serum potassium level is very low.

A patient with congestive heart failure gains 5 pounds in 1 week. This most likely indicates a fluid weight gain of A.½ L. B.1 L. C.2 L. D.3 L.

C.2 L. *Weight gain of 2.2 pounds is equivalent to an excess liter of body fluids.

Which statement will the nurse include when teaching a patient about loop (high-ceiling) diuretics? A.Take the medication at bedtime. B.Take the medication on an empty stomach. C.Rise slowly from a lying or sitting to standing position to prevent dizziness. D.Avoid fruit and vegetables in the diet

C.Rise slowly from a lying or sitting to standing position to prevent dizziness. *: The medication should be taken in the morning, not at bedtime, to prevent sleep disturbances and nocturia; taking the medication at mealtime or with a snack, not on an empty stomach, can prevent nausea from developing, and patients receiving this medication should eat a diet high in fruits and vegetables to prevent hypokalemia.

A patient is taking furosemide (Lasix) 40 mg daily for heart failure and hypertension. It is most important for the nurse to assess the patient for the development of : A.low serum potassium, sodium, and magnesium, and elevated calcium. B.low serum potassium and sodium and elevated magnesium and calcium. C.low serum potassium, sodium, magnesium, and calcium. D.low serum potassium and sodium, with magnesium and calcium remaining normal.

C.low serum potassium, sodium, magnesium, and calcium. *Loop diuretics cause a loss of potassium, sodium, magnesium, and calcium.

Hydrochlorothiazide (HCTZ)

Combined with selected ACE inhibitors, beta blockers, alpha-blockers, angiotensin II blockers, and centrally acting sympatholytics to control htn. Thiazides have a longer half life than of loop diuretics, therefore should be administered in the morning to avoid nocturia. Side effects: dizziness, vertigo, weakness, n/v/d, abd pain, constipation, hyperglycemia, rash, blurred vision, photosensitivity

A patient with chronic glaucoma is most likely to receive which drug? A.A thiazide diuretic B.A loop diuretic C.A potassium-sparing diuretic D.A carbonic anhydrase inhibitor

D. A carbonic anhydrase inhibitor *Carbonic anhydrase inhibitors are primarily used to decrease IOP in patients with open-angle (chronic) glaucoma. Thiazides and loop diuretics are used to treat hypertension and peripheral edema. Potassium-sparing diuretics are used as mild diuretics in combination with other diuretics.

What is the most serious drug interactions that occurs with Thiazide?

Digoxin *Thiazides can cause hypokalemia and hypercalcemia, which enhances action of digoxin, and digoxin toxicity can occur. *Potassium supplements are frequently prescribed. s/s of digitalis toxicity: bradycardia, nausea, vomiting, visual changes *Thiazides also enhance action of lithium and lithium toxicity can occur.

What are diuretics used for?

To decrease htn and to decrease edema (peripheral and pulmonary) in heart failure and renal or liver disorders. *Produce increased urine flow (diuresis), by inhibiting sodium and water reabsorption from the kidney tubules. Diuretics can affect one or more segments of the renal tubules. *Diuretics that act on the tubules closest to the glomeruli have the greatest affect in causing natriuresis (sodium loss in the urine). ex:osmotic diuretic mannitol.

Intermediate-acting thiazides

bendroflumethiazide with Nadolol (Corzide) *For htn and edema associated with HF and cirrhosis. Hypokalemia, hyperglycemia, and hyperuricemia may occur

Examples of loop diuretics

bumetanide: treatment of renal disease and htn and edema associated with HF. Similar effects as furosemide. *ethacrynic acid (Edecrin): for severe edema (pulmonary and peripheral). Potent diuretic with rapid action. Also used for hypercalcemia. Mod to high doses can cause ototoxicity. *Furosemide (Lasix) *Torsemide (Demadex): similar to furosemide

Long-acting thiazides

methyclothiazide *For htn and edema associated with HF and renal or liver dysfunction. Long duration of action. Side effects and drug interactions similar to HCTZ

Potassium-wasting diuretics

promote potassium excretion

Potassium-sparing diuretics

promote potassium retention