ch 32

Introduction to Clinical Pharmacology 

Chapter 32

Diuretics

Learning Objectives

Here’s your ATI/NCLEX HIGH-YIELD DIURETICS CHEAT SHEET — built for exam 3 (simple, priority-based, what kills your patient).

💊 1. Five Types of Diuretics (MUST MEMORIZE)

🔥 CORE CLASSES

1. Thiazide

   • Hydrochlorothiazide (HCTZ)

2. Loop Diuretics 🚨 (STRONGEST)

   • Furosemide (Lasix)

3. Potassium-Sparing

   • Spironolactone

4. Osmotic

   • Mannitol

5. Carbonic Anhydrase Inhibitors

   • Acetazolamide

🧠 2. Uses + Mechanism (KEEP SIMPLE)

⚠ 3. Adverse Effects (NCLEX PRIORITY 🚨)

🚨 BIGGEST TEST POINT = ELECTROLYTES

Thiazide & Loop 🚨

• Hypokalemia 🚨

• Dehydration

• Hypotension

Loop Diuretics 🚨

• Ototoxicity (hearing loss) 🚨

• Severe fluid loss

Potassium-Sparing 🚨

• Hyperkalemia 🚨 (dangerous!)

Osmotic (Mannitol)

• Fluid overload → pulmonary edema 🚨

Carbonic Anhydrase

• Metabolic acidosis

🚫 4. Contraindications & Precautions

🚫 MUST KNOW

⚠ Precautions

• Kidney disease

• Elderly (falls)

• Diabetes (thiazides ↑ glucose)

🔄 5. Interactions (ATI FAVORITE)

🩺 6. Nursing Assessments

BEFORE

✔ BP 🚨
✔ Electrolytes (K⁺, Na⁺) 🚨
✔ Kidney function (BUN/Cr)
✔ Weight (fluid status)

ONGOING (PRIORITY)

✔ Daily weight 🚨 (BEST indicator fluid status)
✔ Intake & output
✔ Electrolytes 🚨
✔ BP (hypotension)
✔ Signs of dehydration

🚨 PRIORITY THINKING

• Low potassium = arrhythmias 🚨

• High potassium = cardiac arrest 🚨

• Rapid weight loss = fluid loss

🧠 7. Nursing Diagnoses

• Excess fluid volume 🚨

• Risk for electrolyte imbalance 🚨

• Risk for decreased cardiac output

• Risk for falls (hypotension)

• Impaired urinary elimination

💡 8. Promote Optimal Therapy

✅ Interventions

• Give in morning (avoid nocturia)

• Monitor weight daily

• Encourage proper diet:

  • ↑ K⁺ (thiazide/loop)

  • ↓ K⁺ (K⁺-sparing)

🚫 Managing Adverse Effects

👩‍🏫 9. Patient Teaching (ATI GOLD)

🚨 MUST KNOW

• Take in morning

• Monitor weight daily 🚨

• Report:

  • Muscle weakness

  • Irregular heartbeat 🚨

🧠 Key Teaching

🥔 Potassium

• Loop/thiazide → eat:

  • Bananas 🍌

  • Potatoes 🥔

• K⁺-sparing → avoid potassium foods

🪑 Safety

• Rise slowly (orthostatic hypotension)

💧 Hydration

• Drink fluids (unless restricted)

🔥 FINAL MEMORY (EXAM GOLD)

• Loops = strongest 🚨

• Loop/thiazide = LOW K⁺

• K⁺-sparing = HIGH K⁺ 🚨

• Daily weight = BEST fluid indicator 🚨

• Ototoxicity = furosemide

• Morning dosing

Common Conditions That Cause Edema

Heart failure

Endocrine disturbances

Kidney and liver diseases

Fluid overload from other causes

Five Types of Diuretics

Loop diuretics

Thiazides and related diuretics

Potassium-sparing diuretics

Osmotic diuretics

Carbonic anhydrase inhibitors

Diuretics—Actions #1

Loop diuretics:

Increase the reabsorption of sodium and chloride in the ascending portion of the loop of Henle 

Blocking the action of reabsorption in the portion of the nephron where a high percentage of sodium and fluid are usually reabsorbed is very effective

Diuretics—Actions #2

Thiazide and related diuretics:

Inhibit reabsorption of sodium and chloride ions in the early distal tubule of nephron 

Results in excretion of sodium, chloride, and water

Often the first drug used in the treatment of hypertension

Diuretics—Actions #3

Potassium-sparing diuretics:

Works by blocking the reabsorption of sodium in the collecting tubules; increases sodium and water in the urine; reduces the excretion of potassium

Spironolactone: antagonizes the action of aldosterone 

Aldosterone: enhances the reabsorption of sodium in the distal convoluted tubules of the kidney

When aldosterone is inhibited, sodium (but not potassium) and water are ewxcreted 

Diuretics—Actions #4

Osmotic diuretics:

Increase the density of the filtrate in the glomerulus 

Prevents the selective reabsorption of water

Sodium and chloride excretion is also increased

Carbonic anhydrase inhibitors:

Sulfonamides without bacteriostatic action that inhibit the enzyme carbonic anhydrase

Results in the excretion of sodium, potassium, bicarbonate, and water

Diuretics—Uses #1

Used in the treatment of: 

edema

hypertension

renal disease

cerebral edema

seizures and altitude sickness

acute glaucoma (infrequently and given topically) for increased intraocular pressure

Diuretics—Uses #2

Used in the treatment of: 

male-to-female hormonal therapy for gender dysphoria (spironolactone) 

short term management of ascites (ethacrynic acid)

premenstrual bloating or weight loss (nonprescription)

Diuretics—Adverse Reactions #1

Neuromuscular System Reactions: 

Dizziness

Lightheadedness

Headache

Weakness

Fatigue

Diuretics—Adverse Reactions #2

Cardiovascular System Reactions: 

Orthostatic hypotension

Electrolyte imbalances

Glycosuria

Diuretics—Adverse Reactions #3

Gastrointestinal System Reactions: 

Anorexia

Nausea

Vomiting

Diuretics—Adverse Reactions #4

Other Reactions: 

Photosensitivity

Extremity paresthesias

Flaccid muscles from hypokalemia

Hyperkalemia (potassium sparing)

Gynecomastia (spironolactone)

Pharmacology in Practice Exercise #1

A nurse is caring for a client with edema due to heart failure. The primary health care provider has prescribed spironolactone for the client. Which of the following adverse reactions to the drug should the nurse monitor for in the client?

Vertigo

Paresthesias

Hyperkalemia

Anorexia

Diuretics—Contraindications

Contraindicated in clients with:

known hypersensitivity to the drug

electrolyte imbalances

severe kidney or liver dysfunction

anuria

active intracranial bleeding (mannitol)

hyperkalemia (potassium-sparing)

pediatrics (potassium sparing) 

Diuretics—Precautions

Use cautiously in clients with:

renal dysfunction; during pregnancy (pregnancy category C), lactation 

Thiazide and loop diuretics: 

Used cautiously in clients with gout, liver disease, diabetes, systemic lupus erythematosus, or diarrhea; pregnancy category B and C

Potassium-sparing diuretics:

Used cautiously in clients with liver disease or diabetes

Diuretics—Interactions #1

Diuretics—Interactions #2

Diuretics—Interactions #3

Diuretics—Interactions #4

Pharmacology in Practice Exercise #2

A primary health care provider has prescribed treatment with an antihypertensive drug along with a diuretic to a client as a treatment for hypertension. The client informs the nurse about his preference for herbal extracts over medical drugs. What information regarding herbal extracts should the nurse provide to the client? Select all that apply

No herbal diuretic should be taken unless approved by the PHCP

Some herbal extracts have been associated with renal damage

Herbal Extracts are more effective than caffeine

Most plant and herbal extracts available as diuretics are nontoxic

Consume diuretic teas like juniper berries

Nursing Process—Client Receiving a Diuretic #1

Preadministration Assessment

Objective Data

Vital signs 

Weight

Description of edema and skin turgor

Description of lung sounds and effort of breathing

Body circumference measurements for peripheral edema on extremities

Input and output

Laboratory tests: Electrolytes

Hepatic and renal function tests

Nursing Process—Client Receiving a Diuretic #2

Preadministration Assessment (continued)

Subjective Data

Ability to engage in toilet activities with increased urination; ambulation difficulty

Medical history of fluid status conditions

Family history of diseases effecting fluid 

Current list of all drugs; diuretics taken in the past

Nursing Process—Client Receiving a Diuretic #3

Ongoing Assessment

Measure and record fluid intake and output

Report to the primary health care provider any marked decrease in the fluid output 

Weigh the client daily

With an outpatient client, ensure client understands to monitor weight daily, and contact provider based on established parameters

Nursing Process—Client Receiving a Diuretic #4

Nursing Diagnosis

Increased Urinary Frequency related to action of the diuretics causing increased bladder filling

Hypovolemia/Dehydration related to excessive diuresis secondary to the administration of a diuretic

Injury Risk related to lightheadedness, dizziness, or cardiac arrhythmias

Nursing Process—Client Receiving a Diuretic #5

Planning

Expected client outcomes depend on the reason for administration of the drug but include:

Optimal response to therapy

Management of adverse drug reactions

Confidence in an understanding of the prescribed medication regimen

Nursing Process—Client Receiving a Diuretic #6

Implementation

Promoting Optimal Response to Therapy

Client with Hypertension

On and outpatient basis, client should be instructed to monitor their blood pressure and pulse

On an inpatient basis, vital signs are monitored frequently

Nursing Process—Client Receiving a Diuretic #7

Implementation

Promoting Optimal Response to Therapy

Client with Edema

Weigh the client daily

Assess the blood pressure, pulse, respiratory rate every 4 hours or more frequently

Assess fluid intake and output every 8 hours or more frequently if needed

Examine areas of edema daily and record findings in the client’s chart 

Monitor general appearance of area with edema

Nursing Process—Client Receiving a Diuretic #8

Implementation

Promoting Optimal Response to Therapy

Client with Increased Intracranial Pressure (Mannitol)

Mannitol is given via IV; inspect solution prior to administration; give at rate to maintain urinary output of 30 to 50 mL/hr

Monitor the urine output, blood pressure, pulse, and respiratory rate

Perform neurologic assessments at specific time intervals

Monitor for signs and symptoms indicating decrease in intracranial pressure

Nursing Process—Client Receiving a Diuretic #9

Implementation

Promoting Optimal Response to Therapy

Client with Renal Compromise (Thiazide Diuretics)

Monitor renal function periodically

Monitor nonprotein nitrogen, BUN, serum uric acid concentrations and serum glucose concentration periodically

Monitor for any joint pain or discomfort 

Pharmacology in Practice Exercise #3

A nurse is caring for a client with renal dysfunction. The PHCP has prescribed a metolazone drug for the client. What should the nurse monitor in the client before administering the drug? Select all that apply.

Serum cholesterol levels

Levels of serum electrolytes

Fluid loss every hour

Creatinine clearance levels

Blood urea nitrogen levels

Nursing Process—Client Receiving a Diuretic #10

Implementation

Promoting Optimal Response to Therapy

Client at Risk of Electrolyte Balances

Monitor for signs and symptoms of electrolyte imbalances

Monitor potassium level in clients taking potassium-sparing diuretics frequently; if serum potassium >5.3 mEq/mL the diuretic is stopped and contact provider

Nursing Process—Client Receiving a Diuretic #11

Implementation

Monitoring and Managing Client Needs

Increased Urinary Frequency

Explain the purpose and effects of the drug to enhance understanding, adherence to drug therapy, and reduce anxiety

Administer the drug early in the day

Make sure that client on bed rest has a call light and a bedpan or urinal within easy reach

Nursing Process—Client Receiving a Diuretic #12

Implementation

Monitoring and Managing Client Needs

Hypovolemia/Dehydration

Encourage clients to eat and drink all food and fluids served at mealtime (potassium rich foods if on a potassium if indicated)

Encourage fluids at frequent intervals throughout the day

Monitor fluid intake and output

Nursing Process—Client Receiving a Diuretic #13

Implementation

Monitoring and Managing Client Needs

Hypovolemia/Dehydration

Assess for signs and symptoms of dehydration or electrolyte imbalance

Dry mouth, thirst, weakness, lethargy, drowsiness, restlessness, muscle pains or cramps, confusion, GI disturbances, hypotension, oliguria, tachycardia, and seizures

Notify health care provider if urinary output is low, if urine is concentrated, or for signs and symptoms of electrolyte imbalance or dehydration

Nursing Process—Client Receiving a Diuretic #14

Implementation

Monitoring and Managing Client Needs

Injury Risk

Frequently monitor pulse rate and rhythm

Report any significant changes in pulse rate or rhythm to the provider

Assist clients who are dizzy but allowed out of bed with ambulatory activities

Nursing Process—Client Receiving a Diuretic #15

Implementation—Educating the Client and Family

Explain the importance of taking the drug at prescribed time intervals and as directed

Advise about the importance of completing the entire course of treatment

Emphasize the importance of taking the drug with food or milk if GI upset occurs

Advise the client to take the drug early in the morning unless the provider directed otherwise

Nursing Process—Client Receiving a Diuretic #16

Implementation—Educating the Client and Family (continued)

Do not reduce fluid intake to reduce the need to urinate

Instruct client to avoid alcohol and nonprescription drugs 

Emphasize observing caution while driving or performing hazardous tasks

Explain necessary interventions if dizziness or weakness or signs of dehydration or electrolyte imbalance occurs; notify provider

Nursing Process—Client Receiving a Diuretic #17

Implementation—Educating the Client and Family (continued)

Instruct client to weigh themselves daily and track their weight; notify provider if weight loss or gain exceeds 3 to 5 pounds in a week.

If foods or fluids high in potassium are recommended by the provider, educate the client about potassium-rich food and fluid sources; caution client not to exceed daily recommended amount

Explain the importance of avoiding exposure to sunlight or ultraviolet light

Nursing Process—Client Receiving a Diuretic #18

Implementation—Educating the Client and Family (continued)

Explain to clients with diabetes mellitus and who take loop or thiazide diuretics to contact health care provider if increase in blood glucose level

Clients on potassium-sparing diuretics: teach clients to avoid eating foods or drinking fluids high in potassium

Clients on thiazide diuretics: explain the necessity of contacting the primary health care provider if sudden joint pain occurs

Clients on carbonic anhydrase inhibitors: explain the necessity of contacting the primary health care provider immediately if eye pain is not relieved or increased; if be being used for a client with seizures, all seizures should be documented

Nursing Process—Client Receiving a Diuretic #19

Evaluation

Was the therapeutic effect achieved and did diuresis occur? 

Were adverse reactions: identified, reported, and managed? 

Urinary elimination occurs without incident

Fluid volume problems are corrected

No injury is evident

Did client and family express confidence and demonstrate understanding of drug regimen?

Turn and Talk—Case Study

A client is admitted to the hospital for treatment of significant edema associated with heart failure. The physician has ordered furosemide (Lasix) IV 1 mg/kg every 6 hours

The client weighs 150 pounds, how many milliliters should the nurse administer every 6 hours if furosemide is available in a 20-mg/mL vial?

During the administration of furosemide, what adverse reactions should the nurse monitor with the client?

The use of furosemide can result in hypokalemia. What are the signs of hypokalemia?