Diuretics & Electrolytes
NURSU 451
Function of the Kidneys
Diuretics most common drug
Function of the
Kidneys




Structure of the
Kidneys



Diuretics:

Pharmacotherapeutics

Primary organs for regulating fluid balance,
electrolyte balance, & acid-base balance
o Regulates blood pressure through the RAAS
o Regulates RBC production
o Filter: 180L retain: 178L blood 2L output
o Produce erythropoietin
Secretes
o Renin
o Erythropoietin
o Calcitriol (hormone)
 Pulls calcium out of bone and increase calcium
levels in blood
Functions by filtration, reabsorption, and excretion in
the nephrons
Filters about 180 liters per day!
o 99% is returned to the bloodstream
o 1% is excreted each day as urine
Nephron
o filters fluid and
makes urine
Bowman capsule
o filter that allows
fluid in,
o but keeps large
particles out
(protein)
 should not
have protein
in urine
Glomerulus
o group of blood
vessels that allow
passage of fluid/waste products and moved into
bladder
A drug that reduces fluid volume in the body & increases
urine output.
o Pulling fluid out of blood and move into kidneys
o #1 reason diuretic is given: fluid overload
Uses:
o
o
o
o
o
o
o
Diuretics:
Pharmacodynamics



Hypertension
CHF (congested heart failure > retaining fluid)
Cirrhosis or liver failure (ascites)
Renal disease
Increased intracranial pressure
Pulmonary edema (fluid in lungs > pneumonia)
Glaucoma = increase fluid and pressure in the eye
Block sodium and water reabsorption in the nephron,
sending more sodium into the urine to be excreted
o Water follows sodium
Increases urine output (diuresis)
Degree of diuresis depends on:
o The part of the tubule affected by the drug
o The potency of the drug
Diuretics: Mechanism
of Action
Diuretics: Nursing
Process

Assessment:
o Obtain complete health history including drug history
(OTC, herbal, Rx)
o Baseline labs
o Electrolytes
o CBC

Diuretics: Nursing
Process



Diuretics: Nursing
Process



Diuretics

o Liver and renal function studies
Baseline assessment
o Weight, vital signs, breath sounds, cardiac monitoring,
edema
o Weight is a great determinant whether diuretics are
working or not
o Loss or gain of 2 lbs in 24 hrs, provider needs to be
notified (not anticipated)
Planning & Interventions:
o Ensure therapeutic effects
 Increased urine output, decreased blood pressure
o Monitor daily weights and intake and output
Minimize adverse effects
o Monitor vital signs, electrolyte levels, BUN, and
creatinine levels
o Monitor nutritional status
o Watch for signs of gout or photosensitivity
Ensure patient understanding of therapy
o Blood urea nitrogen BUN > how hydrated a patient is
>20 = dehydrated
 >1.3 impaired creatinine (overall kidney
function)
Were the patient goals and expected outcomes met?
Name 2 nursing diagnosis appropriate for a patient on
diuretic therapy?
List 3 goals that would be appropriate for a patient on
diuretics?
o How will you measure these goals to ensure they are
being met?
Blocks reabsorption of sodium and water
Loop Diuretics

5 main classes of drugs that
affect urinary output
o Loop Diuretics
o Thiazide Diuretics
o Potassium-sparing Diuretics
o Osmotic Diuretics
o Carbonic Anhydrase
Inhibitors

Potassium most important
electrolyte that should be
monitored

Purpose:
o Blocks the chloride pump in the ascending loop of Henle
o Decreases reabsorption of sodium and chloride
o Causes diuresis even with severe renal impairment
 Works best for patients with impaired kidney
function; liver failure; heart failure; severe HTN
(last resort); hypercalcemia
Indications:
o Pulmonary edema
o Edema caused by liver, cardiac, or kidney disease or
HTN
o To treat hypercalcemia related to kidney stone
formation
o Given PO, IV, or IM
o Given BEFORE 4pm

Loop Diuretics
Loop Diuretics
 Prototype > furosemide (Lasix)
 Adverse Effects
o Dehydration = loss of fluid in the intracellular
Hypotonic solution 0.45%
o Hypotension
o Electrolyte imbalance
 hypokalemia
 hyponatremia
 hypomagnesemia
 hypocalcemia
 hyperglycemia / hyperuricemia (check diabetes pt)
 Ototoxicity
o High doses of furosemide can cause hearing loss
 Priority intervention I & O and weight
Nursing Interventions/Education
o Daily weight/ strict I & O / edema
o
o
o
o
o
Monitor electrolyte levels
Monitor blood pressure
Watch for orthostatic hypotension
Monitor for tinnitus
Educate clients to eat high-potassium foods/ K+
supplements
o Monitor glucose and uric acid levels
o Use cautiously in patients with diabetes or gout
o Do not give late in the day
Thiazide Diuretics


Thiazide Diuretics




Potassium-Sparing
Diuretics

Purpose:
o Block the chloride pump to keep chloride and sodium
in the tubule (to be excreted in urine).
o Promotes diuresis in healthy kidneys
o mild diuretic compared to loop diuretics
Therapeutic Uses:
o 1st choice for essential hypertension
o Treatment of mild-mod edema r/t heart failure or liver
or kidney disease
Prototype > hydrochlorothiazide
Why am I giving it and what to look for if it’s working
Adverse Effects
o Dehydration
o Hypotension
o Electrolyte imbalances
 Hypokalemia
 Hyperglycemia
 Hypercalcemia
o Calcium sparing > retain calcium and can
cause calcium levels to go up
 Hyperuricemia
Nursing Interventions/Education
o Daily weight / I & O / check skin turgor
o Monitor electrolyte levels, uric acid, and
glucose levels
o Educate clients to consume diets high in
potassium
o Do not give during pregnancy
o Take early in the day
o Increased risk for lithium or digoxin toxicity (if
potassium levels drop, digoxin levels stay and can
cause toxicity; lithium needs potassium to be excreted
from the body)
Purpose:
o Blocks the action of aldosterone, causing excretion of
sodium and water > kidneys losing sodium and water
o Promotes retention of potassium
Therapeutic Uses:
o Usually combined with other diuretics
o Heart failure patients or high risk for hypokalemia
o Given orally
Used with furosemide to counteract potassium loss
 Prototype > spironolactone
 Adverse Effects
o Hyperkalemia / arrythmias
o Endocrine effects
o Hirsutism (facial hair), gynecomastia (male
boobies) irregular menses

Potassium-Sparing
Diuretics
Nursing
•
Intervention/Education •
•
•
•
•
•
Osmotic Diuretics
Monitor potassium levels
Never administer potassium supplements with this drug
Regular insulin to tx hyperkalemia
Do not give to clients with renal failure
Do not give with ACE inhibitors
Avoid salt substitutes that contain potassium
Monitor blood pressure and weight

Purpose:
o a sugar that acts to pull large amounts of fluid into the
urine through osmotic pull
o pulls water into the renal
tubule without sodium loss (via
osmosis); leaves sodium, but
pulls water out)
 Therapeutic Uses:
o Acute renal failure (severe
hypotension/shock)
o Decrease intracranial pressure
o Decrease intraocular pressure
(glaucoma)
o Drug overdose (pushes toxic
substances through kidneys)
***Must shake bottle before
administration with filter straw
 Prototype > mannitol
(Osmitrol)
Osmotic Diuretics

Adverse Effects
o Heart failure / pulmonary edema
o Kidney failure
o Severe fluid and electrolyte imbalances
Nursing

Intervention/Education 




Carbonic Anhydrase
Inhibitors


Carbonic Anhydrase
Inhibitors
Monitor for signs of heart failure
Monitor lung sounds
Monitor BUN & Crt
Monitor daily weight/ I&O/ electrolyte levels
Administer IV
Must use filter needle and filter IV tubing
Purpose:
o block the
effects of the
carbonic
anhydrase
enzyme,
slowing down
the movement
of hydrogen
ions
o causes loss of
sodium and
bicarbonate in
the urine
Therapeutic Uses:
o treatment of glaucoma
o used as adjunct to other diuretics
o acute heart failure - edema
 Prototype > acetazolamide
 Adverse Effects
o acid-base and electrolyte imbalances
 metabolic acidosis
 hypokalemia
o paresthesia's
o confusion/drowsiness
o urinary frequency
o renal calculi
o bone marrow suppression
Nursing

Intervention/Education




use cautiously in patients with fluid/electrolyte
imbalances, renal/liver disease, or COPD
monitor for adverse effects and report to HCP
increase potassium in diet/ potassium supplements
monitor CBC
daily weights/ I&Os
Review Questions
A client was prescribed furosemide (Lasix) as an adjunct treatment for hypertension.
What objective data could you collect to determine the therapeutic effectiveness of this
drug?
 BP
 What electrolyte value is most important to check before administering a diuretic?
 Potassium
 What precaution do you need to take when administering mannitol?
 Shake it up and use a filter straw
The nurse is concerned about potassium loss when a diuretic is prescribed for a patient
with ascites and edema. What diuretic may be ordered that spares potassium and
prevents hypokalemia?
 furosemide (Lasix)
 spironolactone (Aldactone)
 torsemide (Demadex)
 bumetanide (Bumex)
The nurse is educating an 80-year-old client diagnosed with heart failure about his
medication regimen. What should the nurse to teach this client about the use of oral
diuretics?
 Avoid drinking fluids for 2 hours after taking the diuretic.
 Take the diuretic in the morning to avoid interfering with sleep.
 Avoid taking the medication within 2 hours consuming dairy products.
 Take the diuretic only on days when experiencing shortness of breath.