Diuretics

Question 1

Diuretics are first line drugs for which 3 conditions?

Answer 1

Heart failure
Hypertension
Acute edematous states (cerebral and pulmonary)

Question 2

Most diuretic drug therapy happens in the _____ (part of the nephron)

Answer 2

Distal tubule (the ascending loop of Henle and the distal convoluted tubule)

Question 3

What percentage of all sodium is reabsorbed in the loop of Henle?

Answer 3

20-25%

Question 4

Loop diuretics, thiazide, and potassium-sparing diuretics work by _____ sodium reabsorption.

Answer 4

blocking/preventing

Question 5

Loop diuretics (1)

Mechanism of action:
Indications:
Adverse effects:
Drug-drug interactions:

Answer 5

Furosemide

Mechanism of action: inhibits sodium and chloride transporters in the ascending loop of Henle. Causes significant diuresis (loss of fluid), leading to reduced edema, reduced venous return, reduced cardiac output). Works quickly, within 5 minutes.

Indications: Edema associated with heart failure, hypertension, and hypercalcemia (drug increases excretion of Ca2+)

Adverse effects: Excessive fluid loss, low NaCl, dehydration (hypotension, thrombosis), potassium depletion (hypokalemia 3.5-5 mmol/L), hyperglycemia (reduces pancreas insulin production)

Drug-drug interactions:
Digoxin - make its effects more pronounced and therefore more toxic (hypokalemia)
Glucocorticoids - increased hypokalemia
Aminoglycosides - ototoxicity

Question 6

Hypokalemia symptoms (4)

Answer 6

Irregular heartbeat (dysrhythmias)
muscle weakness/lethargy
leg cramps
GI disturbances (constipation)

Question 7

Thiazides (1)

Mechanism of action:
Indications:
Adverse effects:
Drug-drug interactions:

Answer 7

Hydrochlorothiazide

Mechanism of action: inhibit reabsorption of sodium and chloride ions in the distal convoluted tubule. Less powerful than loop diuretics.

Indications: hypertension (single or combination therapy), edematous states (adjunct agent)

Adverse effects: hypokalemia, hyperglycemia. IMPOTENCE

Drug-drug interactions:
Digoxin - increased risk of toxicity due to hypokalemia
Antidiabetic drugs - hyperglycemia

Question 8

Potassium-sparing Diuretics (1)

Mechanism of action:
Indications:
Adverse effects:
Drug-drug interactions:

Answer 8

Spironolactone

Mechanism of action: reduce reabsorption of sodium at the distal collecting duct by blocking aldosterone receptors (antagonist). Works slowly, onset 24-48 hours and peak 2-3 days.
IMPORTANTLY: reduces sodium-potassium exchange and body retains K+

Indications: edema (HF), hypertension, reverse potassium loss caused by other two diuretic drugs

Adverse effects: Hyperkalemia (above 5 mmol/L). Sex hormone-like effects, looks like estrogen etc (amenorrhea, gynecomastia)

Drug-drug interactions: ACE inhibitors

Question 9

Hyperkalemia symptoms (3)

Answer 9

Cardiac dysrhythmias (tachycardia)
Muscle weakness
GI - Cramps, nausea, vomiting, diarrhea

Question 10

Digoxin toxicity symptoms (5)

Answer 10

fatigue
GI problems
changes in heart rate and rhythm
loss of appetite (anorexia)
visual disturbances

Question 11

Nursing implications (just a quick review)

Answer 11

take in the morning
monitor serum potassium
eat potassium-rich foods (bananas, dried fruits)
monitor for digoxin toxicity
diabetics watch blood glucose 
change positions slowly