Diuretics Flashcards
How do mercuric compounds work?
Inhibit sodium reabsorption in proximal tubules
no longer used due to adverse effects
How do osmotic diuretics work?
prevent reabsorption of sodium and water from proximal tubule
What is an adverse affect of an osmotic diuretic?
Can cause rapid shift of fluid from interstitial compartment to vascular compartment, causing pulmonary edema or increased cardiac workload
What is mannitol used to treat? How is it administered?
Cerebral edema and elevated ICP
Not absorbed in G.I. tract – must be given IV
Give the equation for central perfusion pressure
CPP = MAP - ICP
Who commonly uses glycerin as a diuretic?
Weightlifters swallow glycerin to decrease water weight due to osmotic diuretic effect
What are aquaretics? Give an example
ADH receptor blockers that increase urine production (Demeclocycline)
What kind of drug can be used to treat patients with SIADH?
Demeclocycline
Which patients commonly have SIADH?
Neuro patients with head trauma/increased ICP
What were the first diuretics used?
Mercury containing compounds
How do you carbonic anhydrase inhibitors work?
They inhibit reabsorption of bicarbonate, causing bicarb waste and water waste
What is a potentially serious adverse reaction of carbonic anhydrase inhibitors?
Hypokalemia due to additional waste of potassium
What are carbonic anhydrase inhibitors mainly used for?
Management of glaucoma – lower intraocular pressure by decreasing aqueous humor production
Why can carbonic anhydrase inhibitor’s affect excretion of other drug products?
Changes in the blood and urine pH alter excretion of drugs
What drugs do carbonic anhydrase inhibitors cross react with?
Sulfonamides- can cause rash
Which diuretic can be used to treat altitude sickness?
Carbonic anhydrase inhibitors – hemoglobin discharges oxygen for increased consumption if blood becomes acidotic (potential effect of CAIs)
What is the only CAI on the market?
Acetazolamide (Diamox)
How do thiazides work?
Prevent reabsorption of sodium and water at the distal tubule
What is the minimum creatinine clearance at which thiazides can be used?
30 mL per minute
What diuretic should be used in cases of reduced CrCl?
Loop diuretics
List five electrolyte related side effects of thiazides
Hypokalemia, hypomagnesemia, hyperuricemia, hyperglycemia, hypercalcemia
Which patients should not take thiazides?
Patients with gout due to thiazide causing increased uric acid production
How quickly do thiazides take effect?
1 to 2 hours
Which type of diuretics cause photosensitivity?
Thiazide – patient should wear sunscreen with at least 15 SPF
Why are diuretics extra helpful in postmenopausal women?
They cause calcium retention, slowing osteoporosis
What time of day should thiazides be taken?
Best in morning, no later then 1700 (5:00)
What is the most common thiazide used?
HCTZ
Which diuretics are known as high ceiling diuretics and high efficacy diuretics?
Loop diuretics
Which type of loop diuretics are more potent and bioavailable?
Bumetanide (#1) and torsemide (#2) (2-4x more effective then furosemide)
How do Loop diuretics work?
They block sodium rehab sorption in the loop of Henle
How can ototoxicity be prevented in administration of Loop diuretics?
Administer slowly over 2 to 3 minutes to avoid ringing in ears
List the two potassium sparing diuretics
Aldosterone antagonists and nonsteroidal potassium sparing diuretics
How do aldosterone antagonists work?
They antagonize aldosterone’s actions: aldosterone Binds to receptors in the distal tubules to stimulate reabsorption of sodium and water and potassium excretion
Must be present for Spironolactone to be effective?
Aldosterone – patient must have functional adrenal gland
List two potential side effects of aldosterone antagonists
Hyperkalemia and gynecomastia
List four uses of Spironolactone
Hypertension, hirtuism, primary aldosteronism, cirrhosis
Why should salt substitutes be avoided when taking aldosterone antagonists?
Salt substitutes often contain potassium rather than sodium and can contribute to hyperkalemia
Which diuretic is better for patients with gout?
Aldosterone antagonists
Name the Second generation aldosterone antagonist with reduced affinity for estrogen receptors
Eplerenone (Inspra)
How do nonsteroidal potassium sparing diuretics work?
Exact mechanism unknown, but affect reabsorption of sodium from the distal tubule
Which diuretics are considered low efficacy?
Potassium sparing
What are three electrolyte related side effects of nonsteroidal potassium sparing diuretics?
Hyperkalemia, hypercalcemia, hypomagnesemia
List two Nonsteroidal potassium sparing diuretics often found in combination with HCTZ
Triamterene and amiloride
List five treatments for hyperkalemia in order of ascending strength
Potassium wasting diuretic, SPS (Kayexalate), bicarbonate, insulin with D5W, calcium chloride
What is the fastest that potassium should be replaced?
No faster than 10 mEq per hour
Which osmotic diuretic is shown to reduce cerebral edema and manage elevated ICP?
Mannitol
