Test 2 Diuretics

Question 1

hydrochlorothiazide: class

Answer 1

• thiazide diuretic

Question 2

hydrochlorothiazide (HCTZ): MOA

Answer 2

• promotes urine production by blocking the reabsorption of Na and Cl in the early segment of the DCT
  
  • retention of Na and Cl in the nephron cause water to be retained, which produces an inc flow of urine
• also promote excretion of potassium

Question 3

how are thiazide diuretics different from loop diuretics?

Answer 3

• the maximum diuresis produced by the thiazides is considerably lower than the maximum diuresis produced by the loop diuretics
• loop diuretics can be effective even when urine flow is decreased, but thiazides cannot, b/c they cannot function when the GFR is low and there is severe renal impairment

Question 4

HCTZ: Indications

Answer 4

• essential HTN
  
  • thiazides are first drug for this
• edema associated with mild to moderate HF
• edema associated with renal or hepatic dz
• diabetes insipidus: HCTZ causes a paradoxical effect for these pts and causes a reduction of urine
• protection against postmenopausal osteoporosis: b/c they promote tubular reabsorption of Ca

Question 5

HCTZ: SEs

Answer 5

• hyponatremia
• hypochloremia
• dehydration
• hypokalemia
• hyperglycemia (only in diabetic pts)
• inc in LDL, total cholesterol, and triglycerides
• hypomagnesmia: muscle weakness, tremor, twitching, dysrhythmias
• hyperuricemia: b/c they cause a retention of uric acid–>gout

Question 6

HCTZ: nursing implications

Answer 6

• evaluate electrolyte levels periodically
• weigh pt to look for dehydration: so make sure to get baseline
• monitor BP
• measure potassium levels, and if fall below 3.5, then need to treat with K supplements or potassium sparing diuretics
  
  • can minimize hypokalemia by eating potassium rich foods
• monitor blood glucose
• measure levels of uric acid periodically
• if administered with digoxin, high risk of toxicity b/c HCTZ promotes K loss
• NSAIDs can blunt the diuretic effects of thiazides
• when only taken once daily, tell pts to take early to minimize nocturia
  
  • if taken BID, then take at 8 AM and 2 PM
• if get stomach upset, take with food

Question 7

triamterene: class

Answer 7

• potassium sparing diuretic

Question 8

triamterene: MOA

Answer 8

• disrupts Na/K exchange in the distal nephron through direct inhibition
  
  • net effect is dec in Na reabsorption and reduction in K secretion, so potassium is conserved
• causes minimal diuresis

Question 9

triamterene: indications

Answer 9

• can be used alone or in combination to treat:
  
  • HTN
  • edema
• when combined with HCTZ, it augments diuresis and helps counteract the potassium wasting effects of HCTZ

Question 10

triamterene: SEs

Answer 10

• nausea
• vomiting
• leg cramps
• dizziness

Question 11

triamterene: ADRs

Answer 11

• hyperkalemia
• blood dyscrasias

Question 12

triamterene: nursing implications

Answer 12

• contraindicated for pts with hyperkalemia
• advise pts to take with or after meals
• intruct pts to restrict intake of potassium rich foods

Question 13

mannitol: class

Answer 13

• osmotic diuretic

Question 14

mannitol: MOA

Answer 14

• freely filtered at glomerulus
• its a hypertonic solution
• undergoes minimal tubular reabsorption
• undergoes minimal metabolism
• pharmacologically inert
• inhibits passive reabsorption of water, so urine flow inc
  
  • ​works by inc osmotic pressure of glomerular filtrate
    
    • more mannitol present, the greater the diuresis

Question 15

mannitol: indications

Answer 15

• prophylaxis of renal failure
  
  • when blood flow to kidney very low, transport mechanisms absorb all Na, Cl, and water, so urine production dec, and kidney failure starts
    
    • filtered mannitol remains in the nephron and draws water with it, so it preserves urine flow and prevents renal failure
• reduction of intracranial pressure that has been elevated by cerebral edema
  
  • draws edematous fluid from brain into the blood
• reduction of intraocular pressure–glaucoma
  
  • draws ocular fluid into the blood (b/c of osmotic force)

Question 16

mannitol: SEs

Answer 16

• headache
• nausea
• vomiting
• fluid and electrolyte imbalance

Question 17

mannitol: ADRs

Answer 17

• edema: b/c mannitol can leave vascular system in all capillaries except in the brain, so it draws water with it
  
  • huge problem in pts with heart dz, b/c may precipitate CHF and pulmonary edema

Question 18

mannitol: nursing implications

Answer 18

• if signs of pulmonary congestion or CHF develop, stop use of drug immediately
• mannitol must also be discontinued if pt with HF or pulmonary edema develop renal failure, b/c accumulation of mannitol would inc risk of cardiac or pulmonary injury

Question 19

furosemide: class

Answer 19

• loop diuretic

Question 20

furosemide: MOA

Answer 20

• acts in the thick segment of the ascending limb of Henle’s loop to block reabsorption of Na and Cl
  
  • by blocking solure reabsorption, furosemide prevents passive reabsorption of water (profound diuresis)

Question 21

furosemide: indications

Answer 21

• reserved for situations that require rapid or massive mobilization of fluid
  
  • so should avoid the drug is less efficacious diuretis will suffice
• pulmonary edema associated with CHF
• edema of hepatic, cardiac, or renal origin that has been unresponsive to less efficacious diuretics
• HTN that cannot be controlled with other diuretics
• especially useful in patients with severe renal impairment, b/c (unlike thiazides) can promote renal diuresis when renal blood flow and GFR are low

Question 22

furosemide: SEs

Answer 22

• hyponatremia
• hypochloremia
• hyperglycemia
• hyperuricemia–>gout
• reduces HDL, and raises LDL and triglycerides–>inc risk of coronary heart dz

Question 23

furosemide: ADRs

Answer 23

• dehydration (dry mouth, thirst, oliguria)
  
  • can be anticipated by excessive loss of weight
  • can promote thrombosis and embolism: headache, pain in chest/calves/pelvis
• HypoTN: due to loss of volume and relaxation of venous smooth muscle which reduces venous return to the heart
• ototoxicity
• maternal/fetal death, abortion

Question 24

furosemide: nursing implications

Answer 24

• monitor weight loss (b/c can indicate dehydration)
• monitor BP
  
  • and teach pt about symptoms of postural hypoTN (dizziness, lightheadedness)
• contraindicated in pregnant patients
• if taking once a day, take in the morning
  
  • if taking BID, then take at 8AM and 2PM
• take with food if GI upset occurs
• promote adherence by informing pt that meds will inc urine volume but effects will subside 6-8 hours after dosing
• watch for signs and symptoms of hypokalemia
  
  • avoid K rich foods