Diuretics Flashcards
What are the five classes of diuretics?
- Osmotic
- Loop (high-ceiling)
- Thiazide and thiazide-like
- Carbonic Anhydrase inhibitors
- Potassium-sparing
What’s the prototype for the five classes of diuretics?
Osmotic =
Loop (high-ceiling) =
Thiazide and thiazide-like =
Carbonic Anhydrase inhibitors =
Potassium-sparing =
Osmotic = mannitol
Loop (high-ceiling) = furosemide
Thiazide and thiazide-like = hydrochlorothiazide
Carbonic Anhydrase inhibitors = acetazolamide
Potassium-sparing = spironolactone
What is the action of mannitol?
-osmotic diuretic (draws fluid from tissues into blood)
-increases the osmotic pressure
-diuresis in the proximal lumen of the nephron
-immediate onset
What is the use of mannitol? ON QUIZ
-Oliguric phase of renal failure (When kidneys are not producing enough urine, mannitol helps flush out the excess fluid)
-decrease pressure for intracranial and spinal cord pressure due to edema
-decrease intraocular pressure (When fluid builds up inside the eyes. Mannitol flushes out)
-used for serious problems
What are the precautions of mannitol?
-do not give to treat basic hypertension because it’s powerful.
-causes dehydration through excess fluid loss
-crystallizes at low temps
-ONLY ADMINISTERED THROUGH FILTER IV help prevent crystallization
Side effects of mannitol? ON QUIZ
-Exits tissues and enters the bloodstream, pulling water with it
(this can lead to increased bp, dehydration, and electrolyte imbalances)
-CHF (congestive heart failure) – due to increased blood volume ⇒ heart works harder to pump all that fluid.
-Pulmonary edema (the heart works harder, and if it can’t pump all that blood, it gets backed up into the lungs ⇒ build up fluid = edema)
What is the action of furosemide?
-high ceiling loop diuretic
-inhibits Na and Cl reabsorption
-direct action in the ascending loop of Henle
(inhibiting Na+ and Cl- reabsorption, they stay in the tubules, and will attract the water to go with them ⇒ more water excreted because we’re trying to decrease BP)
-rapid onset
What is the use of furosemide? ON QUIZ
Go-to drug for hypertension (HTN), (congestive heart failure (CHF), pulmonary edema!
What are the precautions for furosemide?
-Dehydration from fluid loss
-Renal failure
-Can be effective even if the glomerular filtration rate (GFR) is low.
Side effects of furosemide? What is the rationale for Hypokalemia (K) (important for muscle contraction), Hyponatremia (Na), and Hypochloremia (Cl)?
ON QUIZ
-Hypokalemia (K) (important for muscle contraction), Hyponatremia (Na), Hypochloremia (Cl)
-Hyperglycemia (inhibit rate of glucose transport) and Hyperuricemia (gout)
-Can cause reversible hearing loss (1-24 hrs) when IV push TOO FAST
Rationale:
Hypokalemia: at the collecting duct, Na+ is reabsorbed in exchange for K+. Because this drug inhibits Na+, more will be at the collecting duct, therefore, more Na+ will be exchanged for more K+ ⇒ loss of potassium = hypokalemia
Hyponatremia: although at the collecting duct, most of Na+ is exchanged for K+. The % that was lost at the ascending loop of henle = 20%. So, however much Na+ is exchanged at the collecting duct will not make up for that excessive loss.
Hypocloremia: Cl- follows Na+
Potassium Supplements (QUIZ)
Potassium gluconate: 20 mEq (781 mg)
Potassium citrate: 2040 mg mixed with ½ cup water, 4x/day
Potassium-rich foods in fruit, vegetables, fish, and bean category?
Fruit: kiwi, orange, potato, coconut
Veggies: cooked spinach, broccoli
Fish: tuna
Beans: lima beans.
Potassium chloride (K-Dur) (acts as a supplement) (likely on quiz too since it’s a supplement)
Action
Use
Precaution
Side effect
Action: Potassium salt ⇒ replenish electrolytes due to hypokalemia when on diuretics
Uses:
-Hypokalemia
-Vomiting, diarrhea
-Lethal injection ⇒ causes arrhythmia ⇒ ded
Normal potassium lvl: 3.5-5
Precautions:
-Slowly inject into vein. Too fast ⇒ cardiac arrest
-Renal insufficiency
Adverse effects:
-Abdominal pain
-Peptic ulcer disease
-GI bleeding
-Toxicity cardiac block, fibrillation, arrhythmia
Hydrochlorothiazide (HCTZ) action
-thiazide diuretic
-inhibits Na and Cl reabsorption in the early segment of the distal convoluted tubule
-peaks 4-6 hours
Hydrochlorothiazide (HCTZ) uses
ON QUIZ
- hypertension
-congestive heart failure chronic
-edematous states
-diabetes insipidus
Hydrochlorothiazide (HCTZ) precautions
-renal dysfunction
-not effective when glomerular filtration is low
-pregnancy category D (dangerous!)
Hydrochlorothiazide (HCTZ) side effects
ON QUIZ
-hypokalemia, hyponatremia, hypochloremia
-hyperglycemia (glucose), hyperuricemia (uric acid, gout)
-effects minimal when compared to loop diuretics
Acetazolamide action (QUIZ)
-Carbonic anhydrase inhibitor
-Decreases formation of hydrogen ions and bicarbonate from CO2 and water.
Rationale:
Bicarbonate is normally reabsorbed @ proximal tubule. Inhibitor blocks the formation of bicarbonate. And because Na+ follows bicarbonate (and water follows Na+), there’s less of it to reabsorb back @ proximal, therefore increases urine output.
Acetazolamide uses (QUIZ)
-Glaucoma (pressure in the eye)
-Altitude sickness, acute mountain sickness
Acetazolamide precautions
-Hyperchloremic acidosis (high Cl-), low K+, low Na+
-Renal dysfunction
Acetazolamide side effects (QUIZ)
-Numbness, ringing in the ears
-Vomiting, loss of appetite, sleepiness
Spironolactone action
-potassium-sparing diuretic
-Blocks aldosterone @ distal tubule
-induces urinary excretion of sodium and reducing excretion of potassium/hydrogen ions
-peaks 48 hrs
Good to know: Na+ and water are normally reabsorbed back into the body in exchange for K+ with the help of aldosterone. Now aldosterone is blocked ⇒ water out (increase urine output), may increase K+ in body
Spironolactone uses (quiz)
-Chronic CHF
-edema
-preventing diuretic-induced hypokalemia
-Hyperaldosteronism (too much aldosterone)
-Can be given to control hormones
Rationale:
Blocks androgen receptors ⇒ preventing hormone from binding ⇒ reduces hair growth/acne(example).
Spironolactone precautions
renal dysfunction (anuria)
Spironolactone side effects (quiz)
Hyperkalemia
