Diuretic agents outline

Diuretic AgentsDiuretic Agents

Diuretic AgentsDiuretic Agents

• Drugs that accelerate the rate of urine Drugs that accelerate the rate of urine formation.formation.

• Result: removal of sodium and waterResult: removal of sodium and water

SodiumSodium

• Where sodium goes, water follows.Where sodium goes, water follows.

• 20 to 25% of all sodium is reabsorbed 20 to 25% of all sodium is reabsorbed into the bloodstream in the loop of Henle, into the bloodstream in the loop of Henle, 5 to 10% in the distal tubules, and 3% 5 to 10% in the distal tubules, and 3% in collecting ducts.in collecting ducts.

• If it is not absorbed, it is excreted with If it is not absorbed, it is excreted with the urine.the urine.

Diuretic AgentsDiuretic Agents

• Carbonic anhydrase inhibitorsCarbonic anhydrase inhibitors

• Loop diureticsLoop diuretics

• Osmotic diureticsOsmotic diuretics

• Potassium-sparing diureticsPotassium-sparing diuretics

• Thiazide and thiazide-like diureticsThiazide and thiazide-like diuretics

Carbonic Anhydrase InhibitorsCarbonic Anhydrase Inhibitors

(CAIs)(CAIs)

• acetazolamide (Diamox)acetazolamide (Diamox)

• methazolamidemethazolamide

• dichlorphenamidedichlorphenamide

Carbonic Anhydrase Inhibitors: Carbonic Anhydrase Inhibitors: Mechanism of ActionMechanism of Action

• The enzyme carbonic anhydrase helps to make The enzyme carbonic anhydrase helps to make H+ ions available for exchange with sodium and H+ ions available for exchange with sodium and water in the proximal tubules.water in the proximal tubules.

• CAIs block the action of carbonic anhydrase, thus CAIs block the action of carbonic anhydrase, thus preventing the exchange of H+ ions with sodium preventing the exchange of H+ ions with sodium and water.and water.

Carbonic Anhydrase Inhibitors: Carbonic Anhydrase Inhibitors: Mechanism of ActionMechanism of Action

• Inhibition of carbonic anhydrase reduces H+ ion Inhibition of carbonic anhydrase reduces H+ ion concentration in renal tubules.concentration in renal tubules.

• As a result, there is increased excretion of As a result, there is increased excretion of bicarbonate, sodium, water, and potassium.bicarbonate, sodium, water, and potassium.

• Resorption of water is decreased and urine Resorption of water is decreased and urine volume is increased.volume is increased.

Carbonic Anhydrase Inhibitors: Carbonic Anhydrase Inhibitors: Therapeutic UsesTherapeutic Uses

• Adjunct agents in the long-term management Adjunct agents in the long-term management of open-angle glaucomaof open-angle glaucoma

• Used with miotics to lower intraocular pressure Used with miotics to lower intraocular pressure before ocular surgery in certain casesbefore ocular surgery in certain cases

• Also useful in the treatment of:Also useful in the treatment of:

– GlaucomaGlaucoma

– EdemaEdema

– EpilepsyEpilepsy

– High-altitude sicknessHigh-altitude sickness

Carbonic Anhydrase Inhibitors: Carbonic Anhydrase Inhibitors: Therapeutic UsesTherapeutic Uses

• Acetazolamide is used in the management of Acetazolamide is used in the management of edema secondary to CHF when other diuretics edema secondary to CHF when other diuretics are not effective.are not effective.

• CAIs are less potent diuretics than loop diuretics CAIs are less potent diuretics than loop diuretics or thiazides—the metabolic acidosis they induce or thiazides—the metabolic acidosis they induce reduces their diuretic effect in 2 to 4 days.reduces their diuretic effect in 2 to 4 days.

Carbonic Anhydrase Inhibitors: Carbonic Anhydrase Inhibitors: Side EffectsSide Effects

Metabolic acidosisMetabolic acidosis DrowsinessDrowsiness

AnorexiaAnorexia ParesthesiasParesthesias

HematuriaHematuria UrticariaUrticaria

PhotosensitivityPhotosensitivity MelenaMelena

Loop DiureticsLoop Diuretics

• bumetanide (Bumex)bumetanide (Bumex)

• ethacrynic acid (Edecrin)ethacrynic acid (Edecrin)

• furosemide (Lasix)furosemide (Lasix)

Loop Diuretics: Loop Diuretics: Mechanism of ActionMechanism of Action

• Act directly on the ascending limb of the Act directly on the ascending limb of the loop of Henle to inhibit sodium and chloride loop of Henle to inhibit sodium and chloride resorption.resorption.

• Increase renal prostaglandins, resulting in the Increase renal prostaglandins, resulting in the dilation of blood vessels and reduced peripheral dilation of blood vessels and reduced peripheral vascular resistance.vascular resistance.

Loop Diuretics: Drug EffectsLoop Diuretics: Drug Effects

• Potent diuresis and subsequent loss of fluidPotent diuresis and subsequent loss of fluid

• Decreased fluid volume causes:Decreased fluid volume causes:

– Reduced BPReduced BP

– Reduced pulmonary vascular resistanceReduced pulmonary vascular resistance

– Reduced systemic vascular resistanceReduced systemic vascular resistance

– Reduced central venous pressureReduced central venous pressure

– Reduced left ventricular end-diastolic pressureReduced left ventricular end-diastolic pressure

• Potassium depletionPotassium depletion

Loop Diuretics:Loop Diuretics:Therapeutic UsesTherapeutic Uses

• Edema associated with CHF or hepatic Edema associated with CHF or hepatic or renal diseaseor renal disease

• Control of hypertensionControl of hypertension

Loop Diuretics: Side EffectsLoop Diuretics: Side Effects

Body SystemBody System EffectEffect

CNSCNS Dizziness, headache, Dizziness, headache, tinnitus, blurred visiontinnitus, blurred vision

GIGI Nausea, vomiting, Nausea, vomiting, diarrheadiarrhea

Loop Diuretics: Side EffectsLoop Diuretics: Side Effects

Body SystemBody System EffectEffect

HematologicHematologic Agranulocytosis, Agranulocytosis, neutropenia, neutropenia, thrombocytopeniathrombocytopenia

MetabolicMetabolic Hypokalemia, Hypokalemia, hyperglycemia,hyperglycemia,hyperuricemiahyperuricemia

Osmotic DiureticsOsmotic Diuretics

• mannitol (Resectisol, Osmitrol)mannitol (Resectisol, Osmitrol)

Osmotic Diuretics: Osmotic Diuretics: Mechanism of ActionMechanism of Action

• Work in the proximal tubuleWork in the proximal tubule

• Nonabsorbable, producing an osmotic effectNonabsorbable, producing an osmotic effect

• Pull water into the blood vessels and Pull water into the blood vessels and nephrons from the surrounding tissuesnephrons from the surrounding tissues

Osmotic Diuretics: Drug EffectsOsmotic Diuretics: Drug Effects

• Reduced cellular edemaReduced cellular edema

• Increased urine production, causing diuresisIncreased urine production, causing diuresis

• Rapid excretion of water, sodium, and other Rapid excretion of water, sodium, and other electrolytes, as well as excretion of toxic electrolytes, as well as excretion of toxic substances from the kidneysubstances from the kidney

• Reduces excessive intraocular pressureReduces excessive intraocular pressure

Osmotic Diuretics: Osmotic Diuretics: Therapeutic UsesTherapeutic Uses

• Used in the treatment of patients in the early, Used in the treatment of patients in the early, oliguric phase of ARFoliguric phase of ARF

• To promote the excretion of toxic substancesTo promote the excretion of toxic substances

• Reduction of intracranial pressureReduction of intracranial pressure

• Treatment of cerebral edemaTreatment of cerebral edema

Osmotic Diuretics: Side EffectsOsmotic Diuretics: Side Effects

• ConvulsionsConvulsions

• ThrombophlebitisThrombophlebitis

• Pulmonary congestionPulmonary congestion

Also headaches, chest pains, tachycardia,Also headaches, chest pains, tachycardia,blurred vision, chills, and feverblurred vision, chills, and fever

Potassium-Sparing DiureticsPotassium-Sparing Diuretics

• amiloride (Midamor)amiloride (Midamor)

• spironolactone (Aldactone)spironolactone (Aldactone)

• triamterene (Dyrenium)triamterene (Dyrenium)

Potassium-Sparing Diuretics: Potassium-Sparing Diuretics: Mechanism of ActionMechanism of Action

• Work in collecting ducts and distal Work in collecting ducts and distal convoluted tubulesconvoluted tubules

• Interfere with sodium-potassium exchangeInterfere with sodium-potassium exchange

• Competitively bind to aldosterone receptorsCompetitively bind to aldosterone receptors

• Block the resorption of sodium and water Block the resorption of sodium and water usually induced by aldosteroneusually induced by aldosterone

Potassium-Sparing Diuretics: Potassium-Sparing Diuretics: Drug EffectsDrug Effects

• Prevent potassium from being pumped into Prevent potassium from being pumped into the tubule, thus preventing its secretionthe tubule, thus preventing its secretion

• Competitively block the aldosterone Competitively block the aldosterone receptors and inhibit its actionreceptors and inhibit its action

• The excretion of sodium and water The excretion of sodium and water is promotedis promoted

Potassium-Sparing Diuretics: Potassium-Sparing Diuretics: Therapeutic UsesTherapeutic Uses

spironolactone and triamterenespironolactone and triamterene

• HyperaldosteronismHyperaldosteronism

• HypertensionHypertension

• Reversing the potassium loss caused by Reversing the potassium loss caused by

• potassium-losing drugspotassium-losing drugs

amilorideamiloride

• Treatment of CHFTreatment of CHF

Potassium-Sparing Diuretics: Potassium-Sparing Diuretics: Side EffectsSide Effects

Body SystemBody System EffectEffect

CNSCNS Dizziness, headacheDizziness, headache

GIGI Cramps, nausea, Cramps, nausea, vomiting, diarrheavomiting, diarrhea

OtherOther Urinary frequency,Urinary frequency,weaknessweakness**hyperkalemia**hyperkalemia

Potassium-Sparing Diuretics: Potassium-Sparing Diuretics: Side EffectsSide Effects

spironolactonespironolactone

• gynecomastia, amenorrhea, irregular mensesgynecomastia, amenorrhea, irregular menses

Thiazide and Thiazide-Like DiureticsThiazide and Thiazide-Like Diuretics

• hydrochlorothiazide (Esidrix, HydroDIURIL)hydrochlorothiazide (Esidrix, HydroDIURIL)

• chlorothiazide (Diuril)chlorothiazide (Diuril)

• trichlormethiazide (Metahydrin)trichlormethiazide (Metahydrin)

• Thiazide-likeThiazide-like

• chlorthalidone (Hygroton)chlorthalidone (Hygroton)

• metolazone (Mykrox, Zaroxolyn)metolazone (Mykrox, Zaroxolyn)

Thiazide and Thiazide-Like Thiazide and Thiazide-Like Diuretics: Mechanism of ActionDiuretics: Mechanism of Action

• Inhibit tubular resorption of sodium and chloride ionsInhibit tubular resorption of sodium and chloride ions

• Action primarily in the ascending loop of Henle and Action primarily in the ascending loop of Henle and early distal tubuleearly distal tubule

• Result: water, sodium, and chloride are excretedResult: water, sodium, and chloride are excreted

• Potassium is also excreted to a lesser extentPotassium is also excreted to a lesser extent

• Dilate the arterioles by direct relaxationDilate the arterioles by direct relaxation

Thiazide and Thiazide-Like Thiazide and Thiazide-Like Diuretics: Drug EffectsDiuretics: Drug Effects

• Lowered peripheral vascular resistanceLowered peripheral vascular resistance

• Depletion of sodium and waterDepletion of sodium and water

Thiazide and Thiazide-Like Thiazide and Thiazide-Like Diuretics: Therapeutic UsesDiuretics: Therapeutic Uses

• Hypertension Hypertension (one of the most prescribed group of agents for this)(one of the most prescribed group of agents for this)

• Edematous statesEdematous states

• Idiopathic hypercalciuriaIdiopathic hypercalciuria

• Diabetes insipidusDiabetes insipidus

• Adjunct agents in treatment of CHF, hepatic cirrhosisAdjunct agents in treatment of CHF, hepatic cirrhosis

Thiazide and Thiazide-Like Thiazide and Thiazide-Like Diuretics: Side EffectsDiuretics: Side Effects

Body SystemBody System EffectEffect

CNSCNS Dizziness, headache, Dizziness, headache, blurred vision, blurred vision,

paresthesias,paresthesias, decreased libidodecreased libido

GIGI Anorexia, nausea, Anorexia, nausea, vomiting,vomiting, diarrheadiarrhea

Thiazide and Thiazide-Like Thiazide and Thiazide-Like Diuretics: Side EffectsDiuretics: Side Effects

Body SystemBody System EffectEffect

GUGU ImpotenceImpotence

IntegumentaryIntegumentary Urticaria, photosensitivityUrticaria, photosensitivity

MetabolicMetabolic Hypokalemia, glycosuria,Hypokalemia, glycosuria,hyperglycemia hyperglycemia

Diuretic Agents: Diuretic Agents: Nursing ImplicationsNursing Implications

• Perform a thorough patient history and physical Perform a thorough patient history and physical examination.examination.

• Assess baseline fluid volume status, intake and Assess baseline fluid volume status, intake and output, serum electrolyte values, weight, and vital output, serum electrolyte values, weight, and vital signs.signs.

• Assess for disorders that may contraindicate the use Assess for disorders that may contraindicate the use of, or necessitate cautious use of, these agents.of, or necessitate cautious use of, these agents.

Diuretic Agents: Diuretic Agents: Nursing ImplicationsNursing Implications

• Instruct patients to take in the morning as much as Instruct patients to take in the morning as much as possible to avoid interference with sleep patterns.possible to avoid interference with sleep patterns.

• Monitor serum potassium levels during therapy.Monitor serum potassium levels during therapy.

• Potassium supplements are usually not Potassium supplements are usually not recommended when potassium levels exceed recommended when potassium levels exceed 3.0 mEq/L.3.0 mEq/L.

Diuretic Agents: Diuretic Agents: Nursing ImplicationsNursing Implications

• Teach patients to maintain proper nutritional and Teach patients to maintain proper nutritional and fluid volume status.fluid volume status.

• Teach patients to eat more potassium-rich foods Teach patients to eat more potassium-rich foods when taking any but the potassium-sparing agents.when taking any but the potassium-sparing agents.

• Foods high in potassium include bananas, oranges, Foods high in potassium include bananas, oranges, dates, raisins, plums, fresh vegetables, potatoes, dates, raisins, plums, fresh vegetables, potatoes, meat, and fish.meat, and fish.

Diuretic Agents: Diuretic Agents: Nursing ImplicationsNursing Implications

• Patients taking diuretics along with a digitalis Patients taking diuretics along with a digitalis preparation should be taught to monitor for preparation should be taught to monitor for digitalis toxicity.digitalis toxicity.

• Diabetic patients who are taking thiazide and/or Diabetic patients who are taking thiazide and/or loop diuretics should be told to monitor blood loop diuretics should be told to monitor blood glucose and watch for elevated levels.glucose and watch for elevated levels.

Diuretic Agents: Diuretic Agents: Nursing ImplicationsNursing Implications

• Teach patients to change positions slowly, and to Teach patients to change positions slowly, and to rise slowly after sitting or lying to prevent dizziness rise slowly after sitting or lying to prevent dizziness and possible fainting related to orthostatic and possible fainting related to orthostatic hypotension.hypotension.

• Encourage patients to keep a log of their Encourage patients to keep a log of their daily weight.daily weight.

• Encourage patients to return for follow-up visits Encourage patients to return for follow-up visits and lab work.and lab work.

Diuretic Agents: Nursing Diuretic Agents: Nursing ImplicationsImplications

• Patients who have been ill with nausea, vomiting, Patients who have been ill with nausea, vomiting, and/or diarrhea should notify their physician as fluid and/or diarrhea should notify their physician as fluid loss may be dangerous.loss may be dangerous.

• Signs and symptoms of hypokalemia include muscle Signs and symptoms of hypokalemia include muscle weakness, constipation, irregular pulse rate, and weakness, constipation, irregular pulse rate, and overall feeling of lethargy.overall feeling of lethargy.

Diuretic Agents: Diuretic Agents: Nursing ImplicationsNursing Implications

• Instruct patients to notify the physician immediately Instruct patients to notify the physician immediately if they experience rapid heart rates or syncope if they experience rapid heart rates or syncope (reflects hypotension or fluid loss).(reflects hypotension or fluid loss).

• A weight gain of 2 or more pounds a day A weight gain of 2 or more pounds a day or 5 or more pounds a week should be or 5 or more pounds a week should be reported immediately.reported immediately.

Diuretic Agents: Diuretic Agents: Nursing ImplicationsNursing Implications

Monitor for adverse effects:Monitor for adverse effects:

• metabolic alkalosis, drowsiness, lethargy, metabolic alkalosis, drowsiness, lethargy, hypokalemia, tachycardia, hypotension, leg hypokalemia, tachycardia, hypotension, leg cramps, restlessness, decreased mental alertnesscramps, restlessness, decreased mental alertness

Diuretic Agents: Diuretic Agents: Nursing ImplicationsNursing Implications

• Monitor for therapeutic effects:Monitor for therapeutic effects:

– Reduction in edema, fluid volume overload, CHF Reduction in edema, fluid volume overload, CHF

– Reduction of hypertensionReduction of hypertension

– Return to normal intraocular pressuresReturn to normal intraocular pressures