Pharmacology for Nurses Chapter 24

Michael P. Adams, Norman Holland, Carol Quam Urban - Pharmacology for Nurses_ A Pathophysiologic Approach (2020)

what enzyme does the kidneys secrete that helps regulate blood pressure?

what enzyme does the kidneys secrete that helps regulate blood pressure?

renin

what hormone stimulates red blood cell production?

erythropoietin

what do you call something that the kidneys are responsible for producing, is an active form of vitamin D, which helps maintain bone homeostasis?

calcitriol

what is the functional units of the kidney?

nephrons

what do you call a decrease in the kidneys’ ability to maintain electrolyte and fluid balance and to excrete waste products?

kidney failure

what is the primary treatment goals for a patient with kidney failure?

maintain blood flow through the kidneys and adequate urine output

what diagnosis do you perform for kidney failure?

• urinalysis (detects proteinuria & albuminuria, primary measures of structural kidney damage)

• serum creatinine

• BUN

• biopsy

• glomerular filtration rate (GFR) best marker for estimating kidney function, predict onset and progression

what disease requires immediate treatment because it can result in death if untreated?

acute kidney injury

what disease develops over a period of time. patients with this have a medical history of longstanding HTN or Diabetes mellitus

Chronic kidney disease

what is the cause of acute AKI

• Main:renal hypoperfusion

• other: blockage of urinary tract, blood clots to the kidney, severe infection

what is renal hypoperfusion?

lack of sufficient blood flow through the kidneys. this can lead to permanent destruction of nephrons

what are potential causes of hypoperfusion include?

• heart failure

• dysrhythmias

• hemorrhage

• toxins

• dehydrations

what disease is where kidneys are no longer able to function on their own, dialysis and kidney transplantation is the treatment option

end-stage renal disease (ESRD) or end-stage kidney disease

how to mange kidney disease?

• diuretics (to increase urine output)

• cardiovascular drugs (treat underlying HTN or HF)

• dietary management (depending on severity, protein restriction, reduction of sodium, potassium, phosphorus, and magnesium)

what drugs are frequently used in the pharmacotherapy of kidney and cardiovascular disorders?

diuretics

what drug are used for the treatment of HTN, HF, and disorders characterized by accumulation of edema fluid, liver failure or cirrhosis, AKI & CKD

diuretic

what drug increases the rate of urine flow? its goal is to reverse abnormal fluid retention by the body

diuretics

what drug act by preventing the reabsorption of sodium in the nephron loop?

loop diuretics like furosemide (lasix)

what drug act by blocking sodium in the distal convoluted tubule (DCT)?

thiazides

what drug have minimal effect on potassium excretion?

potassium sparing

what drug do you treat anemia with?

epoetin alfa (Epogen) or darbepoetin alfa

what drug do you treat hyperkalemia with?

• dietary restriction of potassium

• patiromer

what drug do you treat hypervolemia with?

• dietary restriction of sodium

• loop diuretics in acute conditions

• thiazide diuretics in mild conditions

what drug do you treat hypocalcemia with?

• usually corrected by reversing the hyperphosphatemia, but additional calcium supplements may be necessary

what drug do you treat metabolic acidosis?

• sodium bicarbonate

• sodium citrate

is it possible to combine 2 or more drugs for HTN and fluid excess disorders? why or why not?

yes

• adverse effects is decreased

• pharmacologic effects like diuresis and BP reduction may be enhanced

• for patient convenience

what is the most effective diuretics?

loop or high-ceiling diuretics

what is the most prescribed loop diuretics? and is able to increase urine output even when blood flow to the kidneys are diminished?

furosemide; unlike thiazide

this diuretics act on the PCT and the nephron loop to create an osmotic force that pulls water into the nephron and increases the excretion of nearly all electrolytes

osmotic diuretics

this diuretics act on the ascending limb of the nephron loop to block the reabsorption of sodium, chloride, and water. excretion of potassium is increased.

loop diuretics

this diuretics act on the early DCT to block the reabsorption of sodium, chloride, and water. excretion of potassium is increased

thiazide diuretics

this diuretics act on the late DCT and collecting ducts to block the reabsorption of sodium and reduce the secretion of potassium. excretion of potassium is not increased

potassium sparing diuretics

what drug do you use to treat HF and HTN?

furosemide (lasix)

what do you do before administering furosemide?

check potassium levels. if K is low, notify doctor before giving

adverse effects of furosemide?

• electrolyte imbalance

• most important is hypokalemia

• dehydration

• hypotension

• ototoxicity

what is the black box warning for furosemide?

is a potent diuretics, if given too much can lead to profound diuresis with water and electrolyte depletion. careful supervision is required

what test must you monitor when taking furosemide?

may increase values of the following:

• BUN

• blood glucose

• serum electrolyte

• serum amylase

• cholesterol

• triglycerides

how do you treat an overdose of furosemide?

replacement of fluids and electrolytes and possible administration of vasopressor like norepinephrine

what drugs are part of the loop diuretics?

• bumetanide (bumex)

• ethacrynic acid (Edecrin)

• furosemide (lasix)

• torsemide (demadex)

how can you tell if your patient is experiencing rapid fluid loss?

signs such as:

• hypotension

• dizziness

• fainting

potassium depletion can cause what?

dysrhythmias; potassium supplements may be prescribed

because of the potential for serious adverse effects, the ____ diuretics are normally reserved for patients with moderate to severe fluid retention, or when other diuretics have failed to achieve therapeutic goals

loop diuretics

what diuretics is primarily use for treatment of mild-moderate HTN; they are less effective at producing diuresis than the loops and are ineffective in patients with severe AKI

thiazide diuretics

what drugs are in thiazide diuretics?

• chlorothiazide (diuril) short acting

• bendroflumethiazide and nadolol (corzide) intermediate acting

• metolaxzone (zaroxolyn) intermediate acting

• chlorthalidone long acting

• indapamide long acting

• methyclothiazide long acting

what are the adverse effects of thiazide diuretics?

• significant hypokalemia

• fatigue

• hypotension

• coma

• hyponatremia

• electrolyte depletion

what is the prototype drug of thiazide diuretics?

hydrochlorothiazide (microzide)

what drug do you use for HTN and edema?

hydrochlorothiazide

what are administration alert for hydrochlorothiazide?

administer drug early to prevent nocturia

what is the adverse effects of hydrochlorothiazide?

• potential electrolyte imbalances due to loss of excessive potassium and sodim

• gout attacks due to tendency to cause hyperuricemia

what is the contraindication of hydrochlorothiazide?

• anuria

• prior hypersensitivity to thiazides or sulfonamides

what labs do you want to monitor while taking hydrochlorothiazide?

may increase:

• serum glucose

• cholesterol

• bilirubin

• triglyceride

• calcium levels

may decrease:

• serum magnesium

• potassium

• sodium

how do you teat hydrochlorothiazide overdose?

is manifested as electrolyte depletion, which is treated with infusion of normal saline. this will also prevent dehydration and hypotension

what drugs act by blocking the actions of the hormone aldosterone. are also called aldosterone antagonists?

spironolactone and eplerenone

patients taking potassium-sparing diuretics should not take what?

potassium supplements or add potassium-rich foods to their diet because taking excess potassium while on these meds may lead to hyperkalemia

what is the most serious adverse effects of thiazide and loop diuretics?

hypokalemia

what diuretic can be taken without affecting blood potassium levels?

potassium-sparing diuretics

what is the prototype of potassium-sparing diuretic or aldosterone antagonist?

spironolactone (aldactone)

what drug reduce edema and is antihypertensive?

spironolactone

administration alert when taking spironolactone?

• give with food to increase absorption

• dont take potassium supplements

what are the adverse effects of spironolactone?

• hyperkalemia (S/S are muscle weakness, fatigue, and bradycardia)

• in men can cause: gynecomastia, impotence, diminished libido

• in women: menstrual irregularities, hirsutism, breast tenderness

contraindications when taking spironolactone?

patient with anuria, serious CKD, or hyperkalemia

what lab tests to monitor while on spironolactone?

may increase plasma cortisol values and interfere with serum glucose determination

what is the treatment for spironolactone overdose?

normal saline to replace fluid and electrolyte lost through diuresis

vasopressor like norepinephrine to raise BP

what does the kidneys regulate?

fluid volume, electrolytes and acid-base balance

what are the 3 major processes of urine formation?

• filtration

• reabsorption

• secretion

• as filtrate travels through the nephron, its composition changes dramatically as a result of the processes of reabsorption and secretion

the dosage levels for most meds mustt be what in patients with kidney failure?

reduced

what may be used to maintain urine output while the cause of the kidney impairment is treated?

diuretics

are drugs that increase urine output, usually by blocking sodium reabsorption? and what are the 3 primary classes?

• diuretics

• loop, thiazide, potassium-sparing diuretics

Which action by the nurse is most important when caring for a patient with chronic kidney disease who has an order for furosemide (Lasix?

1. Assess urine output and renal laboratory values for signs of nephrotoxicity.

2. Check the specific gravity of the urine daily.

3. Eliminate potassium-rich foods from the diet.

   1. Encourage the patient to void every 4 hours.

Answer: 1 Rationale: Because the kidneys excrete most drugs, patients with CKD may need a lower dosage of furosemide (Lasix) to prevent further damage to the kidneys. Options 2, 3, and 4 are incorrect. Urine specific gravity will not adequately assess renal status and may be altered by the diuresis secondary to the furosemide. Potassium should be increased when furosemide, a potent loop diuretic, is ordered and not eliminated. If diuresis is occur-ring, the patient may need to void more often than every 4 hours. Cognitive Level: Analyzing. Nursing Process: \n Implementation. Client Need: Physiological Integrity.

The patient admitted for heart failure has been receiving hydrochlorothiazide (Microzide). Which laboratory levels should the nurse carefully monitor? (Select all that apply.)

1. Platelet count

2. White blood cell count

3. Potassium

4. Sodium

5. Uric acid

Answer: 3, 4, 5 Rationale: Thiazide diuretics such as hdrochlorothiazide (Microzide) cause loss of sodium and potassium and may cause hyperuricemia. Options 1 and 2 are incorrect. Hydrochlorothiazide does not have a direct effect on blood cells. Cognitive Level: \n Analyzing. Nursing Process: Evaluation. Client Need: \n Physiological Integrity.

Which of the following clinical manifestations may indicate that the patient taking metolazone (Zaroxolyn) is experiencing hypokalemia?

1. Hypertension

2. Polydipsia

3. Cardiac dysrhythmias

4. Skin rash

Answer: 3 Rationale: Metolazone (Zaroxolyn) is a thiazide diuretic and causes potassium loss. Signs of hypo-kalemia include cardiac dysrhythmias, hypotension, dizziness, and syncope. Options 1, 2, and 4 are incorrect. \n Polydipsia is not associated with hypokalemia. HTN is a clinical indication for the use of diuretics. Skin rashes are an adverse effect of metolazone but are not a symptom of hypokalemia. Cognitive Level: Analyzing. Nursing Process: Evaluation. Client Need: Physiological Integrity.

The nurse is providing teaching to a patient who has been prescribed furosemide (Lasix). Which of the following should the nurse teach the patient?

1. Avoid consuming large amounts of kale, cauli-flower, or cabbage.

2. Rise slowly from a lying or sitting position to standing.

3. Count the pulse for one full minute before taking this medication.

4. Restrict fluid intake to no more than 1 L per 24-hour period.

1. Answer: 2 Rationale: Loop diuretics such as furosemide (Lasix) may dramatically reduce a patient's circulating blood volume from diuresis and may cause orthostatic hypotension. To minimize the chance for syncope and falls, the patient should be taught to rise slowly from a lying or sitting position to standing. Options 1, 3, and 4 are incorrect. Kale, cauliflower, and cabbage contain vitamin K, which does not need to be restricted during diuretic therapy. Monitoring the pulse along with the blood pressure to assess for reflex tachycardia is advised, but the pulse does not need to be taken for one full minute before taking the drug. Fluids should not be restricted during diuretic therapy unless ordered by the provider. Cognitive Level: Analyzing. Nursing Process: \n Implementation. Client Need: Physiological Integrity.

While planning for a patient's discharge from the hos-pital, which teaching points would be included for a patient going home with a prescription for chlorothia-zide (Diuril)?

1. Increase fluid and salt intake to make up for the losses caused by the drug.

2. Increase intake of vitamin-C rich foods, such as grapefruit and oranges.

3. Report muscle cramping or weakness to the healthcare provider.

4. Take the drug at night because it may cause drowsiness.

5. Answer: 3 Rationale: Muscle cramping or weakness may indicate hypokalemia and should be reported to the healthcare provider. Options 1, 2, and 4 are incor-rect. Patients on diuretic therapy are taught to monitor sodium (salt) and water intake to maintain adequate, but not excessive, amounts. Vitamin C-rich foods do not need to be increased while a patient is taking chlo-rothiazide. The drug should be taken early in the day to avoid nocturia. It does not cause drowsiness. Cognitive Level: Applying. Nursing Process: Planning. Client Need: Physiological Integrity.

Apatient with a history of heart failure will be started on spironolactone (Aldactone). Which drug group should not be used, or used with extreme caution in patients taking potassium-sparing diuretics?

1. Nonsteroidal anti-inflammatory drugs

2. Corticosteroids

3. Loop diuretics

4. Angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers

Answer: 4 Rationale: ACE inhibitors and ARBs taken concurrently with potassium-sparing diuretics increase the risk of hyperkalemia. Options 1, 2, and 3 are incorrect. NSAIDs are used cautiously with all diuretics because they are excreted through the kidney.

Corticosteroids and loop diuretics mav cause hupoka-lemia and may be paired with a potassium-sparing diuretic to reduce the risk of hypokalemia developing if a diuretic is needed. Cognitive Level: Apply-ing. Nursing Process: Implementation. Client Need:

Physiological Integrity.

Naomi Saltzman is an 82-year-old with a history of HTN and a myocardial infarction resulting in heart failure three years ago, managed by furosemide (Lasix) 20 mg/ daily, digoxin (Lanoxin) 0.125 mg / daily, and potassium supplements (K-Dur) 20 mEq/daily. She has remained active, but relies on a neighbor for transportation to the pharmacy and market. Recently, the neighbor has been out of town for 2 weeks, and Naomi discovered that she had not calculated the need for medication refills before her neighbor left. She ran out of her K-Dur, but figured that since it was just a "supplement," it could wait until the neighbor returned. After taking medical transport services to her healthcare provider for her recheck, she is noted to have generalized weakness and fatigue. She has lost 3.6 kg (8 lb) since her last clinic visit 6 weeks ago. Her blood pressure is 104/62 mmHg, her heart rate is 98 beats/ min and slightly irregular, her respiratory rate is 20 breaths/min, and her body temperature is 36.2°C (97.2°F). The blood specimen collected showed a serum sodium level of 130 mE/L and a potassium level of 3.2 mEq/ L. Naomi is diagnosed with dehydration and hypokalemia.

1. Discuss fluid and electrolyte imbalances related to the following diuretic therapies: a. Loop diuretics b. Thiazide diuretics C. Potassium-sparing diuretics d. Osmotic diuretics

2. What relationship exists between Naomi's diuretic therapy and hypokalemia?

3. What patient education should the nurse provide Naomi about her medications?

1. a Loop diuretics act on the ascending nephron loop in the kidney and are considered potent diuret-ics. They are primarily used in medicine to treat HTN and edema, often due to heart failure (HF) or chronic kidney disease. Although all electrolytes may be lost due to diuretic therapy, it is potassium that is most severely lost and presents the greatest problem to patients receiving this drug. b. Thiazide diuretics also deplete the body's potassium levels and cause the body to lose magnesium. Thiazides are used to lower blood pressure and are frequently used in combination with other drugs to treat HTN. c. Potassium-sparing diuretics do not promote the secretion of potassium into the urine. They are also used as adjunctive therapy in the treatment of HTN and HE. d. Osmotic diuretics work through the diffusion of fluid through semipermeable membranes by creating a shift in fluid from intercellular and interstitial areas to the intravascular space. Initially, due to the increase in the circulating volume, the nurse should monitor the patient for fluid overload. Because of shifting fluid volume, they may cause electrolytes to increase or decrease, and electrolyte levels should be monitored frequently.

2. Most diuretics potentially create a deficit of potassium. Hypokalemia predisposes the patient to digoxin toxicity (see Chapter 27 for information about digoxin).

3. The patient taking diuretics should be instructed to do the following:

• Take the medication exactly as prescribed.

• Watch for electrolyte imbalances and dehydration and take steps to prevent such from occurring.

• Weigh weekly and report significant changes to the healthcare provider, such as weight gain of 1 kg (2 Ibs) in 24 hours.

• Consult the prescriber before consumingOTC medications.

• Rise slowly to minimize orthostatic hypotension.

A43-year-old man is diagnosed with HTN following an annual physical examination. The patient is thin and states that he engages in fairly regular exercise, but he describes his job as highly stressful. He also has a positive family history for HTN and stroke. The healthcare provider initiates therapy with hydrochlo-rothiazide (Microzide). The patient asks the nurse, "I have high blood pressure. Why do I need a 'water pill' to help my blood pressure?" How does hydrochloro-thiazide reduce blood pressure?

Hydrochlorothiazide acts on the kidney tubule to decrease the reabsorption of Na*. When hydrochloro-thiazide blocks this reabsorption, more Na* is sent into the urine. When sodium moves across the tubule water flows with it; thus, blood volume decreases and blood pressure falls. Thiazide diuretics are often ordered as a drug of choice in the treatment of HTN.

A 54-year-old female patient has been treated with chlorothiazide (Diuril) for HTN. Due to increasing blood pressure, edema, and signs of early heart fail-ure, the provider switches her to a low dose of furosemide (Lasix) and spironolactone (Aldactone). The patient wants to know why she now needs two diuretics and questions the nurse about whether this is a safe thing to do. How should the nurse respond?

Thiazide diuretics such as chlorothiazide are often used in the treatment of HTN. When the blood pressure is not adequately controlled or signs of heart failure, such as increasing edema or night-time cough indicating pulmonary congestion, develop, a more potent loop diuretic such as furosemide (Lasix) may be ordered to increase diuresis. Because furosemide increases the amount of potassium lost from the body, a K-sparing diuretic such as spironolactone (Aldactone) may be ordered. Giving spironolactone with furosemide enhances diuretic action while limiting potassium loss.