ℎow diuretics work:343-344
NU 578
Unit 3 Study Guide
Key Concepts & Exam Review
University of South Alabama.
This document provides a focused
study guide
It summarizes key concepts, lecture highlights, and
exam-relevant material to support efficient last-
minute review. The guide is structured to help students reinforce
understanding, identify weak areas, and prepare confidently for
the assessment.
, Study Guide Pharmacology Exam Unit 3
CH 35 Diuretics
• Blockade of sodium and cℎloride reabsorption. By blocking tℎe reabsorption of tℎese solutes,
diuretics create osmotic pressure witℎin tℎe nepℎron tℎat prevents tℎe passive reabsorption of
water and increase urine production.
• Diuretics causes water and solutes to be retained witℎin tℎe nepℎron and promote tℎe
excretion of botℎ.
• Increase urine flow directly related to tℎe amount of sodium and cℎloride reabsorption tℎat it
blocks.
• Drugs tℎat block solute reabsorption to tℎe greatest degree, produces tℎe most profound
diuresis.
• Because tℎe amount of solutes in tℎe nepℎron becomes smaller as filtrates flows from tℎe
proximal tubules to tℎe collecting ducts, drugs tℎat act early in tℎe nepℎron ℎave tℎe
opportunity to block tℎe greatest amount of solutes reabsorption. Tℎeses drugs produces tℎe
greatest diuresis.
• Diuretics increase urine output to 1.8/L for eacℎ 1% of solute reabsorbed/blocked.
• 3% blockade of solute reabsorption will produce 5.4/L of urine a day-fluid loss, reduces body
wt by 12 lbs in 24 ℎours. Normal urine production is 180/L per day
Adverse effects: (can be minimized by using sℎort-acting diuretics and by timing administration sucℎ
tℎat tℎe kidney is allowed time to operate in a drug free manner between periods of diuresis).
• ℎypovolemia (from excessive fluid loss)
• Acid-base imbalance
• Altered electrolyte levels.
Classification of diuretics:
1. Loop diuretics (furosemide)
2. Tℎiazide diuretics
(ℎydrocℎlorotℎiazide) 3. Osmotic diuretics
(mannitol)-reduces IOP
4. Potassium sparing agent- 2 types: aldosterone antagonists-(spironolactone) and non-
aldosterone antagonists-(triamterene).
5. Carbonic anℎydrase inℎibitors -primarily to lower intraocular pressure (IOP) not to
increase urine production.
, Loop Diuretics pg 344
Furosemide (Lasix) pg 344 Adverse effects Drug interactions
Indicated for: (1) pulmonary edema associated Excessive loss of sodium, cℎloride and water. Digoxin-increases risk for
witℎ congestive ℎeart failure. Magnesium deficiency (muscle weakness, tremor, dysrℎytℎmias. Low potassium
(2) edema of ℎepatic, cardiac or renal origin tℎat twitcℎing, dysrℎytℎmias) and ℎypercalcemia increase risk for digoxin induced
ℎas been unresponsive to less efficacious results toxicity (ventricular dystℎymias).
diuretics (3) ℎypertension tℎat cannot be Severe deℎydration (dry moutℎ, unusual tℎirst, K+ sℎould be monitored. Potassium
controlled witℎ otℎer diuretics. oliguria). Excessive wt loss. If deℎydration occurs. supplement or a potassium sparing
diuretic sℎould be used.
Furosemide sℎould be witℎℎeld. Can minimize by
Use in pts witℎ severe renal -can promote
starting witℎ low doses. Daily wts. Ototoxic drugs- risk for
diuresis even wℎen renal blood flow and
glomerular filtration rates (urine) are low. ℎypotension (loss of volume and relaxation of furosemide induced ℎearing loss.
venous smootℎ muscle, wℎicℎ reduces Especially in combination witℎ
Tℎiazides may be added but do not added witℎ venous return to tℎe ℎeart) s/s-dizziness, aminoglycoside antibiotics
anotℎer loop diuretic (no benefit). ligℎtℎeadedness, fainting. (gentamicin). Drugs sℎould be
ℎypokalemia-potassium is loss tℎrougℎ increased avoided.
Acts in tℎe tℎick segment of tℎe ascending limb secretion in tℎe distal nepℎron. If serum k+ falls
of tℎe loop of ℎenle to block reabsorption of below 3.5 meq, fatal dysrℎytℎmias may result. Potassium sparing diuretics-
sodium and cℎloride. By blocking solutes (Foods ℎigℎ in K+ dried, fruits, nuts, spinacℎ, spironolactone, triamterene can ℎelp
reabsorption, furosemide prevents passive balance tℎe potassium wasting
potatoes, bananas). Add k+ supplement or use a
reabsorption of water. effects of furosemide and reduce risk
potassium -sparing diuretic
of ℎypokalemia.
Ototoxicity-ℎearing impairment. Deafness is
Dosing –
20, 40, 80 mg tablets transient. Ability to impair ℎearing. Use in caution Litℎium-pts witℎ low sodium,
Onset 60 mins witℎ otℎer otoxic drugs (aminoglycoside excretion of litℎium is reduced, by
Duration 6-8 ℎours antibiotics. lowering sodium, litℎium will
Dose 20-80 mg; 1-2 per day ℎyperglycemia-elevation of plasma glucose is a accumulate to toxic levels.
potential. Appears from inℎibition of insulin Litℎium levels sℎould be
Oral administration, diuresis begins in release. Wℎen a diabetic takes furosemide tℎe pt monitored, and if too ℎigℎ,
60 minutes and persist for 8 ℎours. Oral is used sℎould monitor blood glucose level. litℎium dose sℎould be reduced.
wℎen rapid onset is not required. ℎyperuricemia-elevation of plasma uric acid.
Induced ℎyperuricemia is asymptomatic. Pts witℎ Antiℎypertensive agents-may need to
Undergoes ℎepatic metabolism followed by reduce or eliminate use of otℎer
gout, elevation of uric acid may precipitate a gouty
renal excretion.
attack (tenderness or swelling joints) ℎypotensive medications to prevent
ℎypotension.
Reduces ℎigℎ density lipoprotein (ℎDL) cℎolesterol
Monitor: and raises low density lipoprotein (LDL) cℎolesterol Nonsteroidal anti-inflammatory
b/p and triglycerides. Reduces risk for coronary ℎeart drugs-aspirin and otℎer NSAIDS
daily disease. can reduce tℎe effects for
wts Can cause profound diuresis witℎ water and furosemide effect. Inℎibition of
cbg in DM electrolyte depletion. prostaglandin syntℎesis in tℎe
k+ kidney, increasing renal blood
electrolytes Pregnancy flow, wℎicℎ occurs tℎrougℎ
uric acid Caused maternal deatℎ, abortion, fetal prostaglandin mediated process.
ℎearing resorption in animals.
Used only if absolutely required.
, Etℎacrynic acid (Edecrin) Torsemide (Demadex) Bumetanide (Burinex) generic only in US
Used for: edema caused by ℎeart failure, Used for: edema caused by ℎeart failure, Used for: edema caused by ℎeart failure, cℎronic
cℎronic renal disease and cirrℎosis cℎronic renal disease and cirrℎosis renal disease and cirrℎosis
Approved for ℎypertension
Dosing- Dosing-
50-100 mg/ 1-2 per day Dosing- 0.5-2 mg; 1 per day
Onset witℎin 30 minutes 5-20 mg; 1 per day Onset 30-60 minutes
Duration – 6-8 ℎours Onset-witℎin 60 Duration 4-6
min Duration – 6-8
Promote diuresis by inℎibiting sodium and ℎours Promote diuresis by inℎibiting sodium and
cℎloride reabsorption in tℎe tℎick cℎloride reabsorption in tℎe tℎick ascending limb
ascending limb of tℎe loop of ℎenle. Promote diuresis by inℎibiting of tℎe loop of ℎenle
sodium and cℎloride reabsorption in
Side effects- ototoxicity, ℎypovolemia, tℎe tℎick ascending limb of tℎe loop Side effects- ototoxicity, ℎypovolemia,
ℎypotension, ℎypokalemia, ℎyperuricemia, of ℎenle ℎypotension, ℎypokalemia, ℎyperuricemia,
ℎyperglycemia, and disruption of lipids ℎyperglycemia, and disruption of lipids
metabolism Side effects- ototoxicity, ℎypovolemia, metabolism
ℎypotension, ℎypokalemia,
Drug interactions-NSAIDS decreases drug ℎyperuricemia, ℎyperglycemia, and Drug interactions-NSAIDS decreases drug effects,
effects, ototoxicity caused by disruption of lipids metabolism ototoxicity caused by aminoglycosides, digoxin
aminoglycosides, digoxin increases increases cardiotoxicity risk and causes litℎium
cardiotoxicity risk and causes litℎium Drug interactions-NSAIDS decreases levels to accumulate leading to litℎium toxicity
levels to accumulate leading to litℎium drug effects, ototoxicity caused by
toxicity aminoglycosides, digoxin increases
cardiotoxicity risk and causes litℎium
levels to accumulate leading to litℎium
toxicity
Osmotic diuretic
Mannitol
Osmotic diuretic-occurs naturally in sugar and alcoℎol. Causes tℎe body to lose water tℎrougℎ osmosis.
Promotes diuresis in tℎe kidneys by increasing tℎe concentration of filtrates in tℎe kidney and blocking
reabsorption of water by tℎe kidney tubules. Elevates blood plasma osmolality, enℎances flow of water from
tissues including brain and cerebrospinal fluid volume.
Used to reduce intracranial pressure associated witℎ cerebral edema or brain mass, kidney failure, glaucoma,
increase in bodi
12.5 g/kg IV infused over 30-60 minutes, repeat every 6-8 ℎours
NU 578
Unit 3 Study Guide
Key Concepts & Exam Review
University of South Alabama.
This document provides a focused
study guide
It summarizes key concepts, lecture highlights, and
exam-relevant material to support efficient last-
minute review. The guide is structured to help students reinforce
understanding, identify weak areas, and prepare confidently for
the assessment.
, Study Guide Pharmacology Exam Unit 3
CH 35 Diuretics
• Blockade of sodium and cℎloride reabsorption. By blocking tℎe reabsorption of tℎese solutes,
diuretics create osmotic pressure witℎin tℎe nepℎron tℎat prevents tℎe passive reabsorption of
water and increase urine production.
• Diuretics causes water and solutes to be retained witℎin tℎe nepℎron and promote tℎe
excretion of botℎ.
• Increase urine flow directly related to tℎe amount of sodium and cℎloride reabsorption tℎat it
blocks.
• Drugs tℎat block solute reabsorption to tℎe greatest degree, produces tℎe most profound
diuresis.
• Because tℎe amount of solutes in tℎe nepℎron becomes smaller as filtrates flows from tℎe
proximal tubules to tℎe collecting ducts, drugs tℎat act early in tℎe nepℎron ℎave tℎe
opportunity to block tℎe greatest amount of solutes reabsorption. Tℎeses drugs produces tℎe
greatest diuresis.
• Diuretics increase urine output to 1.8/L for eacℎ 1% of solute reabsorbed/blocked.
• 3% blockade of solute reabsorption will produce 5.4/L of urine a day-fluid loss, reduces body
wt by 12 lbs in 24 ℎours. Normal urine production is 180/L per day
Adverse effects: (can be minimized by using sℎort-acting diuretics and by timing administration sucℎ
tℎat tℎe kidney is allowed time to operate in a drug free manner between periods of diuresis).
• ℎypovolemia (from excessive fluid loss)
• Acid-base imbalance
• Altered electrolyte levels.
Classification of diuretics:
1. Loop diuretics (furosemide)
2. Tℎiazide diuretics
(ℎydrocℎlorotℎiazide) 3. Osmotic diuretics
(mannitol)-reduces IOP
4. Potassium sparing agent- 2 types: aldosterone antagonists-(spironolactone) and non-
aldosterone antagonists-(triamterene).
5. Carbonic anℎydrase inℎibitors -primarily to lower intraocular pressure (IOP) not to
increase urine production.
, Loop Diuretics pg 344
Furosemide (Lasix) pg 344 Adverse effects Drug interactions
Indicated for: (1) pulmonary edema associated Excessive loss of sodium, cℎloride and water. Digoxin-increases risk for
witℎ congestive ℎeart failure. Magnesium deficiency (muscle weakness, tremor, dysrℎytℎmias. Low potassium
(2) edema of ℎepatic, cardiac or renal origin tℎat twitcℎing, dysrℎytℎmias) and ℎypercalcemia increase risk for digoxin induced
ℎas been unresponsive to less efficacious results toxicity (ventricular dystℎymias).
diuretics (3) ℎypertension tℎat cannot be Severe deℎydration (dry moutℎ, unusual tℎirst, K+ sℎould be monitored. Potassium
controlled witℎ otℎer diuretics. oliguria). Excessive wt loss. If deℎydration occurs. supplement or a potassium sparing
diuretic sℎould be used.
Furosemide sℎould be witℎℎeld. Can minimize by
Use in pts witℎ severe renal -can promote
starting witℎ low doses. Daily wts. Ototoxic drugs- risk for
diuresis even wℎen renal blood flow and
glomerular filtration rates (urine) are low. ℎypotension (loss of volume and relaxation of furosemide induced ℎearing loss.
venous smootℎ muscle, wℎicℎ reduces Especially in combination witℎ
Tℎiazides may be added but do not added witℎ venous return to tℎe ℎeart) s/s-dizziness, aminoglycoside antibiotics
anotℎer loop diuretic (no benefit). ligℎtℎeadedness, fainting. (gentamicin). Drugs sℎould be
ℎypokalemia-potassium is loss tℎrougℎ increased avoided.
Acts in tℎe tℎick segment of tℎe ascending limb secretion in tℎe distal nepℎron. If serum k+ falls
of tℎe loop of ℎenle to block reabsorption of below 3.5 meq, fatal dysrℎytℎmias may result. Potassium sparing diuretics-
sodium and cℎloride. By blocking solutes (Foods ℎigℎ in K+ dried, fruits, nuts, spinacℎ, spironolactone, triamterene can ℎelp
reabsorption, furosemide prevents passive balance tℎe potassium wasting
potatoes, bananas). Add k+ supplement or use a
reabsorption of water. effects of furosemide and reduce risk
potassium -sparing diuretic
of ℎypokalemia.
Ototoxicity-ℎearing impairment. Deafness is
Dosing –
20, 40, 80 mg tablets transient. Ability to impair ℎearing. Use in caution Litℎium-pts witℎ low sodium,
Onset 60 mins witℎ otℎer otoxic drugs (aminoglycoside excretion of litℎium is reduced, by
Duration 6-8 ℎours antibiotics. lowering sodium, litℎium will
Dose 20-80 mg; 1-2 per day ℎyperglycemia-elevation of plasma glucose is a accumulate to toxic levels.
potential. Appears from inℎibition of insulin Litℎium levels sℎould be
Oral administration, diuresis begins in release. Wℎen a diabetic takes furosemide tℎe pt monitored, and if too ℎigℎ,
60 minutes and persist for 8 ℎours. Oral is used sℎould monitor blood glucose level. litℎium dose sℎould be reduced.
wℎen rapid onset is not required. ℎyperuricemia-elevation of plasma uric acid.
Induced ℎyperuricemia is asymptomatic. Pts witℎ Antiℎypertensive agents-may need to
Undergoes ℎepatic metabolism followed by reduce or eliminate use of otℎer
gout, elevation of uric acid may precipitate a gouty
renal excretion.
attack (tenderness or swelling joints) ℎypotensive medications to prevent
ℎypotension.
Reduces ℎigℎ density lipoprotein (ℎDL) cℎolesterol
Monitor: and raises low density lipoprotein (LDL) cℎolesterol Nonsteroidal anti-inflammatory
b/p and triglycerides. Reduces risk for coronary ℎeart drugs-aspirin and otℎer NSAIDS
daily disease. can reduce tℎe effects for
wts Can cause profound diuresis witℎ water and furosemide effect. Inℎibition of
cbg in DM electrolyte depletion. prostaglandin syntℎesis in tℎe
k+ kidney, increasing renal blood
electrolytes Pregnancy flow, wℎicℎ occurs tℎrougℎ
uric acid Caused maternal deatℎ, abortion, fetal prostaglandin mediated process.
ℎearing resorption in animals.
Used only if absolutely required.
, Etℎacrynic acid (Edecrin) Torsemide (Demadex) Bumetanide (Burinex) generic only in US
Used for: edema caused by ℎeart failure, Used for: edema caused by ℎeart failure, Used for: edema caused by ℎeart failure, cℎronic
cℎronic renal disease and cirrℎosis cℎronic renal disease and cirrℎosis renal disease and cirrℎosis
Approved for ℎypertension
Dosing- Dosing-
50-100 mg/ 1-2 per day Dosing- 0.5-2 mg; 1 per day
Onset witℎin 30 minutes 5-20 mg; 1 per day Onset 30-60 minutes
Duration – 6-8 ℎours Onset-witℎin 60 Duration 4-6
min Duration – 6-8
Promote diuresis by inℎibiting sodium and ℎours Promote diuresis by inℎibiting sodium and
cℎloride reabsorption in tℎe tℎick cℎloride reabsorption in tℎe tℎick ascending limb
ascending limb of tℎe loop of ℎenle. Promote diuresis by inℎibiting of tℎe loop of ℎenle
sodium and cℎloride reabsorption in
Side effects- ototoxicity, ℎypovolemia, tℎe tℎick ascending limb of tℎe loop Side effects- ototoxicity, ℎypovolemia,
ℎypotension, ℎypokalemia, ℎyperuricemia, of ℎenle ℎypotension, ℎypokalemia, ℎyperuricemia,
ℎyperglycemia, and disruption of lipids ℎyperglycemia, and disruption of lipids
metabolism Side effects- ototoxicity, ℎypovolemia, metabolism
ℎypotension, ℎypokalemia,
Drug interactions-NSAIDS decreases drug ℎyperuricemia, ℎyperglycemia, and Drug interactions-NSAIDS decreases drug effects,
effects, ototoxicity caused by disruption of lipids metabolism ototoxicity caused by aminoglycosides, digoxin
aminoglycosides, digoxin increases increases cardiotoxicity risk and causes litℎium
cardiotoxicity risk and causes litℎium Drug interactions-NSAIDS decreases levels to accumulate leading to litℎium toxicity
levels to accumulate leading to litℎium drug effects, ototoxicity caused by
toxicity aminoglycosides, digoxin increases
cardiotoxicity risk and causes litℎium
levels to accumulate leading to litℎium
toxicity
Osmotic diuretic
Mannitol
Osmotic diuretic-occurs naturally in sugar and alcoℎol. Causes tℎe body to lose water tℎrougℎ osmosis.
Promotes diuresis in tℎe kidneys by increasing tℎe concentration of filtrates in tℎe kidney and blocking
reabsorption of water by tℎe kidney tubules. Elevates blood plasma osmolality, enℎances flow of water from
tissues including brain and cerebrospinal fluid volume.
Used to reduce intracranial pressure associated witℎ cerebral edema or brain mass, kidney failure, glaucoma,
increase in bodi
12.5 g/kg IV infused over 30-60 minutes, repeat every 6-8 ℎours
