Diuretic DrugsDiuretic Drugs- Drugs that accelerate the rate of urine formation- Result in the removal of sodium and water- Used in the treatment of hypertension, heart failure, and renal failureSodium- In the nephron, where sodium goes, water followso 60% to 70% of sodium and water is returned to bloodstream by the proximal tubuleo 20% to 25% of all sodium is reabsorbed into the bloodstream in the ascending loop of Henleo 5% to 10% is reabsorbed in the distal tubuleso 3% is reabsorbed in collecting ducts- If water is not absorbed, it is excreted as urineTypes of Diuretic Drugs- Carbonic anhydrase inhibitors- Loop diuretics- Osmotic diuretics- Potassium-sparing diuretics- Thiazide and thiazide-like diureticsLoop Diuretics- bumetanide (Bumex) – alternative - ethacrynic acid (Edecrin)- furosemide (Lasix)- torsemide (Demadex)- Mechanism of Actiono Possess renal, cardiovascular, and metabolic effectso Act directly on the ascending limb of the loop of Henle to inhibit chloride and sodium resorptiono Increase renal prostaglandins, resulting in the dilation of blood vessels and reduced peripheral vascular resistanceo Useful in treatment of edemao Normal 24 hour urine output is 800-2400 - Drug Effectso Potent diuresis and subsequent loss of fluido Decreased fluid volume causes a reduction in:o Blood pressureo Pulmonary vascular resistanceo Systemic vascular resistanceo Central venous pressureo Left ventricular end-diastolic pressureo Potassium and sodium depletion- Indicationso Edema associated with HF or hepatic or renal diseaseo To control hypertensiono To increase renal excretion of calcium in patients with hypercalcemiao In cases of HF resulting from diastolic dysfunctiono Excellent at treating asciteso Give in morning – increases urinary output - Adverse Effectso Central nervous system (CNS): Dizziness, headache, tinnitus, blurred visiono Gastrointestinal (GI): Nausea, vomiting, diarrheao Integumentary: Stevens-Johnson syndrome (torsemide) – rare unless on it long term o Hematologic: Agranulocytosis, neutropenia, thrombocytopenia o Metabolic: Hypokalemia, hyperglycemia, hyperuricemiaOsmotic Diuretics- Examples: mannitol (Osmitrol) (Most used osmotic diuretic), Urea, Organic acids, Glucose- Mechanism of Actiono Work mostly in the proximal tubuleo Nonabsorbable, producing an osmotic effecto Pull water into the renal tubules from the surrounding tissueso Inhibit tubular resorption of water and solutes, thus producing rapid diuresis- Drug Effectso Increases glomerular filtration rate and renal plasma flow—helps to prevent kidney damage during acute renal failureo Reduces intracranial pressure or cerebral edema associated with head traumao Reduces excessive intraocular pressure- Indicationso Treatment of patients in the early, oliguric phase of acute renal failure (ARF)o To promote excretion of toxic substanceso To reduce intracranial pressureo Treatment of cerebral edemao NOT indicated for peripheral edema- Adverse Effectso Convulsionso Thrombophlebitis – slow pusho Pulmonary congestiono Also headaches, chest pains, tachycardia, blurred vision, chills, and fever- Mannitol (Osmitrol)o Intravenous infusion onlyo May crystallize when exposed to low temperatureso Use of a filter is requiredo Clear color, no sediment Potassium-Sparing Diuretics- amiloride (Midamor)- spironolactone (Aldactone) – 1st, prototype - triamterene (Dyrenium)- Also known as aldosterone-inhibiting diuretics- Mechanism of Actiono Work in collecting ducts and distal convoluted tubuleso Interfere with sodium-potassium exchangeo Competitively bind to aldosterone receptorso Block resorption of sodium and water usually induced by aldosterone- Drug Effectso Prevent potassium from being pumped into the tubule, thus preventing its secretiono Competitively block aldosterone receptors and inhibit their actiono Promote the excretion of sodium and water- Indicationso spironolactone and triamterene Hyperaldosteronism – excessive hair growth Hypertension  Reversing potassium loss caused by potassium-losing drugs Certain cases of HFo amiloride Treatment of HF- Adverse Effectso CNS: Dizziness, headacheo GI: Cramps, nausea, vomiting, diarrheao Other: Urinary frequency, weakness, hyperkalemiao spironolactone (Aldactone) Gynecomastia Amenorrhea Irregular menses Postmenopausal bleedingThiazide and Thiazide-like Diuretics- Thiazide diureticso **hydrochlorothiazide (Esidrix, HydroDIURIL) (HCTZ)o chlorothiazide (Diuril)- Thiazide-like diureticso metolazone (Mykrox, Zaroxolyn) o chlorthalidone (Hydone, Thalitone)o indapamide (Lozol)- Mechanism of Actiono Inhibit tubular resorption of sodium, chloride, and potassium ionso Action primarily in the distal convoluted tubuleo Result: water, sodium, and chloride are excretedo Potassium is also excreted to a lesser extento Dilate the arterioles by direct relaxation- Drug Effectso Lowered peripheral vascular resistanceo Depletion of sodium and water (and potassium)o Thiazides should not be used if creatinine clearance is less than 30 to 50 mL/min (normal is 125 mL/min)o Metolazone remains effective to a creatinine clearance of 10 mL/mino Very few side effects - Indicationso Hypertension (one of the most prescribed group of drugs for this)o Edematous stateso Idiopathic hypercalciuria (don’t see often)o Diabetes insipiduso Heart failure due to diastolic dysfunctiono Adjunct drugs in treatment of edema related to HF, hepatic cirrhosis, or corticosteroid or estrogen therapy- Adverse Effectso CNS: Dizziness, headache, blurred visiono GI: Anorexia, nausea, vomiting, diarrheao GU: Impotenceo Hematologic: Jaundice, leukopeniao Integumentary: Urticaria, photosensitivityo Metabolic: Hypokalemia, hyperglycemia, hyperuricemia, hypochloremic alkalosisNursing Implications- Perform a thorough patient history and physical examination- Assess baseline fluid volume status, intake and output, serum electrolyte values, weight, and vital signs—especially postural BPs- Assess for disorders that may contraindicate or necessitate cautious use of these drugs- Instruct patients to take the medication in the morning if possible to avoid interference with sleep patterns- Monitor serum potassium levels during therapy- Teach patients to maintain proper nutritional and fluid volume status- Teach patients to eat more potassium-rich foods when taking any but the potassium-sparing drugso Foods high in potassium include bananas, oranges, dates, apricots, raisins, broccoli, green beans,