Pharmacology Chapter 43 - Diuretics Flashcards

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Increased urine flow



Sodium loss in the urine



Used to decrease hypertension and decrease edema in pts with HF and renal or liver disorders. Diuretics have an antihypertensive effect because they promote sodium and water loss by blocking sodium and chloride reabsorption causing a decrease in fluid volume, lowering BP.


What categories of diuretics are used to treat HTN and HF?

  • Thiazide
  • Loop
  • Potassium Sparing


Thiazide Diuretics

Promote sodium, chloride, and water excretion. Also can caouse loss of potassium and magnesium, but they promote calcium re-absorption. They are used for patients with NORMAL renal fx. They can be effective as antihypertensives.


Thiazide Diuretics

Side Effects/Adv. Rxn

  • Hypercalcemia
  • Hyperglycemia
  • Hypokalemia
  • Hypochloremia
  • Hypomagnesemia
  • Hyperuricemia (elevated uric acid level)
  • Hyperlipidemia (increase LDL, triglycerides)
  • Minimal Bicarbonate loss

Total Cholesterol: <200 mg/dL
LDL: <100mg/dL


Thiazide Diuretics

Contraindications/Drug Interactions


  • Renal Failure
  • Elevated BUN, Creatinine

Drug Interactions:

  • Thiazides can cause hypokalemia which enhances action of Digoxin
  • Thiazides enhance action of lithium


Thiazide Diuretics

Hydrochlorothiazide (HCT) Prototype p. 623

All information from the group of Thiazide Diuretics apply to HCT.

HCT has a longer half life than loop diuretics, so it should be given in the morning to avoid nocturia.

Take with food to avoid GI upset

SE: dizziness, nausea, vomiting, constipation, photosensitivity, headache, weakness


Thiazide Diuretics

Info from Nsg. Process

  • Obtain drug history: interactions possible with digoxin, corticosteroids, antidiabetics, ginko, licorice
  • Monitor vitals, electrolytes: K, glucose, uric acid, cholesterol levels
  • Slowly change positions to avoid orthostatic hypotension
  • Eat foods rich in potassium. Potassium supplements may be ordered
  • Wear sunblock for photosensitivity


Loop (High Ceiling) Diuretics

Loop's promote the loss of Na, K, Ca, Mg, and H2O. They are more potent than thiazides. They are potassium wasting diuretics. Loop's are NOT effective as antihypertensives. Never combine 2 Loop diuretics.

Loop diuretics can be used for patients with decreased renal function.


Loop (High Ceiling) Diuretics

Side Effects/ Adv. Rxn

  • Most common are fluid and electrolyte imbalances: hypokalemia, hyponatremia, hypocalcemia, hypomagnesmia, hypochloremia
  • orthostatic hypotension


Loop (High Ceiling) Diuretics

Drug interactions

  • Digitalis


Loop (High Ceiling) Diuretics

furosemide (Lasix) Prototype p. 626

All information from the group of Loop Diuretics apply to Lasix.

Take early to avoid nocturia. Take with food to avoid GI upset.

Contraindicated: anuria, hypersensitivity to sulfonamides because it's a sulfonamide derivative.

Side Effects: nausea diarrhea, constipation, headache, weakness, photosensitivity, hyperglycemia, HEARING LOSS with too rapid IV administration.


Loop (High Ceiling) Diuretics

Info from Nsg. Process

  • Drugs that may interact: alcohol, animoglycosides, anticoagulants, corticosteroids, lithium, digitalis, Coumadin
  • Urinary output should be at least 30 mL/hr
  • Be alert for marked decrease in BP
  • Administer IV Lasix slowly; hearing loss may occur if rapidly injected.


S/S of Hypokalemia

  • Muscle weakness
  • ab distension
  • leg cramps
  • cardiac dysrhythmias


Carbonic Anhydrase Inhibitors

Used only for patients with open angle glaucoma. It decreases IOP.

This group blocks the action of the enzyme carbonic anhydrase, which is needed to maintain the body's acid base balance, causing increased Na, K, and bicarbonate excretion. With long term use, metabolic ACIDOSIS can occur.


  • acetazolamide (Diamox)
  • Methazolamide (Neptazane)


Osmotic Diurectics

Promote Na, Cl, K, and H2O excretion. Used to prevent kidney failure, to decrease ICP, and to decrease IOP.

Pulmonary edema can occur from rapid shift of fluids.

EX: Mannitol:

Mannitol must be given with extreme caution to pts with heart disease and HF.


Potassium Sparing Diuretics

These are weaker than thiazides and loop diuretics. They are used as mild diuretics, or in combo with another diuretic. No potassium supplements are needed. They promote Na and H2O excretion and K retention.


Potassium Sparing Diuretics

side effects/adv rxn

  • The main SE is hyperkalemia
  • If given with an ACE inhibitor, hyperkalemia could become severe or life threatening.


Potassium Sparing Diuretics

spironolactone (Aldactone)

Prototype p. 630

Action: Blocks the action of aldosterone and inhibits the sodium potassium pump (ie, K is retained and Na is excreted). As a result of the action, the heart rate is MORE REGULAR.

Should not be taken with: ACE inhibitors, ARBs

Can be used in combo with a potassium wasting diuretic to intensify the diuretic effect and prevent K loss.

Give in the morning

SE: nausea, vomiting, diarrhea, dizziness, headache, weakness


Potassium Sparing Diuretics

Info from Nsg Process

  • Observe for s/s of hyperkalemia
  • take with food to avoid GI upset
  • if K levels are high advise pt to avoid foods rich in K


S/S hyperkalemia

  • Nausea
  • Diarrhea
  • Ab cramping
  • numbness and tingling of the hands and feet
  • Leg cramps
  • Tachycardia and later bradycardia
  • Oliguria


A patient is taking furosemide (Lasix) 40 mg daily for heart failure and hypertension. It is most important for the nurse to assess the patient for the development of

A.low serum potassium, sodium, and magnesium, and elevated calcium.

B.low serum potassium and sodium and elevated magnesium and calcium.

C.low serum potassium, sodium, magnesium, and calcium.

D.low serum potassium and sodium, with magnesium and calcium remaining normal.

Answer: C

Rationale: Loop diuretics cause a loss of potassium, sodium, magnesium, and calcium.


Which statement will the nurse include when teaching a patient about loop (high-ceiling) diuretics?

A.Take the medication at bedtime.

B.Take the medication on an empty stomach.

C.Rise slowly from a lying or sitting to standing position to prevent dizziness.

D.Avoid fruit and vegetables in the diet.

Answer: C

Rationale: The medication should be taken in the morning, not at bedtime, to prevent sleep disturbances and nocturia; taking the medication at mealtime or with a snack, not on an empty stomach, can prevent nausea from developing, and patients receiving this medication should eat a diet high in fruits and vegetables to prevent hypokalemia.


A patient is admitted to the intensive care unit with increased intracranial pressure. The nurse would anticipate administering

A.furosemide (Lasix).

B.mannitol (Osmitrol).

C.triamterene (Dyrenium).

D.spironolactone (Aldactone).

Answer: B

Rationale: Osmotic diuretics such as mannitol (Osmitrol) increase the osmolality and sodium reabsorption in the proximal tubule and loop of Henle. Sodium, chloride, potassium, and water are excreted. This group of drugs is used to prevent kidney failure, to decrease intracranial pressure, and to decrease intraocular pressure. Mannitol is a potent osmotic potassium-wasting diuretic frequently used in emergency situations such as ICP and IOP.


A patient is receiving furosemide (Lasix). It is most important for the nurse to monitor the patient for the development of





Answer: B

Rationale: Hypokalemia is the most common electrolyte balance associated with furosemide (Lasix) therapy.


A patient with congestive heart failure gains 5 pounds in 1 week. This most likely indicates a fluid weight gain of

A.½ L.

B.1 L.

C.2 L.

D.3 L.

Answer: C

Rationale: Weight gain of 2.2 pounds is equivalent to an excess liter of body fluids.


Before administering triamterene (Dyrenium), it is most important for the nurse to determine if the patient is also receiving

A.digoxin (Lanoxin).

B.potassium chloride (K-Dur).

C.acetaminophen (Tylenol).

D.doxazosin (Cardura).

Answer: B

Rationale: Triamterene (Dyrenium) is a potassium-sparing diuretic. Potassium supplementation is not indicated unless the patient’s serum potassium level is very low.


Which statement about aldosterone does the nurse identify as being true? Aldosterone

A.promotes sodium excretion. a mineralocorticoid hormone.

C.promotes potassium retention. secreted by the pancreas.

Answer: B

Rationale: Aldosterone is a mineralocorticoid hormone that promotes sodium retention


A patient with chronic glaucoma is most likely to receive which drug?

A.A thiazide diuretic

B.A loop diuretic

C.A potassium-sparing diuretic

D.A carbonic anhydrase inhibitor

Answer: D

Rationale: Carbonic anhydrase inhibitors are primarily used to decrease IOP in patients with open-angle (chronic) glaucoma. Thiazides and loop diuretics are used to treat hypertension and peripheral edema. Potassium-sparing diuretics are used as mild diuretics in combination with other diuretics.


Which laboratory value will the nurse report to the health care provider as a potential adverse response to hydrochlorothiazide?

  1. Sodium level of 140 mEq/L
  2. Fasting blood glucose level of 140 mg/dL
  3. Calcium level of 9 mg/dL
  4. Chloride level of 100 mEq/L


Hydrochlorothiazide can cause hyperglycemia. Normal calcium level is approximately 8.8-10.3 mg/dL; normal sodium level is 135-147 mEq/L; normal chloride level is 95-107 mEq/L, and normal fasting blood glucose should be 60-110 mg/dL.


What is the best information for the nurse to provide to the patient who is receiving spironolactone (Aldactone) and furosemide (Lasix) therapy?

  1. “Moderate doses of two different diuretics are more effective than a large dose of one.”
  2. “This combination promotes diuresis but decreases the risk of hypokalemia.”
  3. “This combination prevents dehydration and hypovolemia.”
  4. “Using two drugs increases the osmolality of plasma and the glomerular filtration rate.”


Spironolactone is a potassium-sparing diuretic; furosemide causes potassium loss. Giving these together minimizes electrolyte imbalance. It is not accurate to state that the drug combination prevents dehydration and hypovolemia or that it increases the osmolality of plasma and the glomerular filtration rate. Stating that giving two different diuretics is more effective is not specific enough information for the patient.


The nurse is assessing a patient who is taking furosemide (Lasix). The patient’s potassium level is 3.4 mEq/L; chloride is 90 mmol/L, and sodium is 140 mEq/L. Based on the nurse’s understanding of the laboratory results, what prescribed therapy can the nurse anticipate administering?

  1. Mix 40 mEq of potassium in 250 mL D5W and infuse rapidly.
  2. Administer sodium polystyrene sulfonate.
  3. Administer 2 mEq potassium chloride per kilogram per day IV.
  4. Administer calcium acetate, two tablets three times per day.


Furosemide is a potent loop diuretic, resulting in the loss of potassium as well as water, sodium, and chloride. The patient needs chloride replacement. Normal potassium level is 3.5 to 5.2 mEq/L; normal sodium level is 135 to 147 mEq/L, and normal chloride level is 95 to 107 mEq/L. Potassium is never given by rapid infusion.


A patient taking spironolactone (Aldactone) has been taught about the medication. Which menu selection indicates that the patient understands teaching related to this medication?

  1. Potatoes
  2. Lima beans
  3. Chicken
  4. Strawberries


Spironolactone is a potassium-sparing diuretic that could potentially cause hyperkalemia. Chicken is the only appropriate choice of the foods listed because it is lower in potassium. Potatoes, lima beans, and strawberries are all known to contain high levels of potassium.


Which patient would the nurse need to assess first if the patient is receiving mannitol (Osmitrol)?

  1. A 67-year-old patient with type 1 diabetes mellitus
  2. A 21-year-old patient with a head injury
  3. A 47-year-old patient with anuria
  4. A 55-year-old patient receiving cisplatin to treat ovarian cancer


Mannitol (Osmitrol) is not metabolized but excreted unchanged by the kidneys. Potential water intoxication could occur if mannitol is given to a patient with anuria. Mannitol is safe to use with diabetic patients and those with head injuries, and it may function as a nephroprotectant when cisplatin is being used.


A patient is prescribed chlorthalidone (Thalitone). What is the most important information the nurse will teach the patient?

  1. “Do not drink more than 10 ounces of fluid a day while on this medication.”
  2. “Take this medication on an empty stomach.”
  3. “Take this medication before bed each night.”
  4. “Wear protective clothing and sunscreen while taking this medication.”


Adverse effects associated with chlorthalidone include photosensitivity. The nurse should teach the patient to protect himself when out in the sun. There is no evidence that fluid should be restricted while taking the medication, that it should be taken on an empty stomach, or that it should only be taken at bedtime.


A patient with acute pulmonary edema is receiving furosemide (Lasix). What assessment finding indicates to the nurse that the intervention is working?

  1. Potassium level decreased from 4.5 to 3.5 mEq/L
  2. Improvement in mental status
  3. Lungs clear
  4. Output 30 mL/hr


Furosemide (Lasix) is a potent, rapid-acting diuretic that would be the drug of choice to treat acute pulmonary edema. Furosemide should not cause a drastic change in output or decrease in potassium level, and there is no evidence that it will create any change in mental status.


Which assessment indicates to the nurse a therapeutic effect of mannitol (Osmitrol) has been achieved?

  1. Decreased intracranial pressure
  2. Decreased potassium
  3. Increased urine osmolality
  4. Decreased serum osmolality


Mannitol (Osmitrol) is an osmotic diuretic that pulls fluid from extravascular spaces into the bloodstream to be excreted in urine. This will decrease intracranial pressure, increase excretion of medications, decrease urine osmolality, and increase serum osmolality


What intervention will the nurse perform when monitoring a patient receiving triamterene (Dyrenium)?

  1. Assess urinary output every other day.
  2. Monitor for side effect of hypoglycemia.
  3. Assess potassium levels.
  4. Monitor for hypernatremia.


Triamterene (Dyrenium) is a potassium-sparing diuretic. The nurse should monitor potassium for potential hyperkalemia.


A patient is ordered furosemide (Lasix) to be given via intravenous push. Which interventions will the nurse perform? (Select all that apply.)

  1. Administer at a rate no faster than 20 mg/min.
  2. Assess lung sounds before and after administration.
  3. Assess blood pressure before and after administration.
  4. Maintain accurate intake and output record.
  5. Monitor ECG continuously.
  6. Insert an arterial line for continuous blood pressure monitoring.

1 2 3 4

Furosemide (Lasix) can be infused via intravenous push at the rate of 20 mg/min. Furosemide is a diuretic and will decrease fluid in alveoli, and assessing lung sounds can help to determine therapeutic effect. Blood pressure should decrease with the administration of a diuretic. It is appropriate to monitor before and after administration. It is appropriate to monitor intake and output for a patient receiving a diuretic. There is no need to insert an arterial line to continuously monitor the blood pressure since it should not fluctuate that dramatically. Also, there is no need to continuously monitor ECG since the medication is not cardiotoxic.