Diuretics Flashcards
SIADH (Syndrome of Inappropriate Antidiuretic Hormone)
Excessive levels of ADH are produced
The body retains too much water and electrolytes may become depleted in the blood
May be caused by: Meningitis, encephalitis, brain tumors, psychoses, lung diseases, head trauma, some medications, and damage to the hypothalamus or pituitary gland
How the body corrects for alkalosis (not enough H)
Respiratory system decreases respiratory rate and retains CO2, forming into carbonic acid which neutralizes the excess OH
The kidneys eliminate excess bicarbonate by reabsorbing more Cl and less HCO3, and retain H by secreting more K (this may cause hypokalemia)
How the body corrects for acidosis (too much H)
Respiratory system increases respiratory rate and removes CO2, which removes carbonic acid
The kidneys reabsorb more bicarbonate (instead of Cl), and secrete H instead of K (may cause hyperkalemia)
Edema
Accumulation of fluid in tissues or body cavity
May be cased by: Cardiac edema (congestive heart failure), acute pulmonary edema, liver disease, renal disease, or pregnancy
When correcting, CAUTION with hypokalemia (especially if on digitalis)
Thiazides and Thiazide-Like Diuretics
Chlorothiazide, Chlorthalidone
Indicated for: Hypertension (first-line drug), fluid retention, acute pulmonary edema, and fluid retention during pregnancy
MOA: Inhibits bicarbonate ion reabsorption at the PCT and chloride ion reabsorption at the ascending loop of Henle; also vasodialates
May cause: Fatigue, GI symptoms, hypokalemia, hyperglycemia (in diabetics), uric acid in blood (aggravates gout), and skin rashes (sensitivity reaction)
ONLY DIURETIC SAFE FOR PREGNANCY
Furosemide
Thiazide/Loop Diuretic
Indicated for: EMERGENCY, congestive heart failure, acute pulmonary edema, acute hypertension, and chronic renal failure
MOA: Vasodilation, inhibition of Cl reabsorption from ascending loop of Henle
May cause: Electrolyte imbalance (hypokalemia and alkalosis), dehydration, hypotension, and temporary or permanent deafness
8 - 10 TIMES MORE POWERFUL THAN OTHER LOOP DIURETICS
CAN CAUSE UP TO 4 LITERS OF URINE TO BE FORMED UPON INITIAL ADMINISTRATION
Ethacrynic Acid, Bumetanide, and Torsemide
Loop Diuretics
Indicated for: Edema (no vasodilator effects)
MOA: Inhibits sodium ion reabsorption from the PCT and inhibits chloride ion reabsorption from the ascending loop of Henle
May cause: Toxicity (worsens with chronic use), dehydration, hypotension, hypokalemia, alkalosis, temporsry or permanent deafness, and rare myalgia
RAPID ONSET
Carbonic Anhydrase Inhibitors
No longer used as diuretics. Used for acute glaucoma
Spirolactone/Aldosterone Antagonists
Potassium Sparing Diuretics
MOA: inhibits aldosterone at the DCT, decreases potassium secretion, dependent on aldosterone levels in system, does not decrease K levels
May cause: Hyperkalemia, gynecomastia in males
USED WHEN OTHER DIURETICS TOXIC/INEFFECTIVE, OR INCOMBINATION EITH A THIAZIDE
NO EFFECT ON ADRENALECTOMIZED PATIENT OR ADDISON’S PATIENT
Trimeterene, Amiloride
Potassium Sparing Diuretics
MOA: Decreases potassium secretion by antagonizing aldosterone receptors, independent of aldosterone in system, does not decrease K levels
May cause: Hyperkalemia, elevation of blood urea, and elevation of blood glucose
USED IN COMBINATION WITH THIAZIDE (Dyazide = triamterene [KSD] + hydrochlorothiazide [thiazide])
Mannitol
Osmotic Diuretic
Indicated for: Withdrawing water from overhydrated cells, maintaining renal volume to prevent renal failure after shock/hemorrhage/surgery, and help eliminate drug OD from barbiturates, salicylates, etc.
MOA: Adds sugar to the body to draw out water from cells osmotically
Cautions: Congestive heart failure, pulmonary edema, severe hypertension, circulatory overload, and transient increase in blood pressure
DOES NOT ELIMINATE Na, NOT USEFUL FOR EDEMA
