Thiazide Diuretics

Question 1

What is the mechanism of action of thiazide diuretics?

Answer 1

Inhibition of Na/Cl symporter is the distal convoluted tubule
Increase in reabsorption of Ca due to stimulation of Na/Ca counter transporter

Question 2

What drugs are thiazide diuretics?

Answer 2

Chlorothiazide, Hydrochorothiazide, Trichlormethiazide, Chlorthalidone

Question 3

What are thiazide diuretics referred to as?

Answer 3

rescue diuretics

Question 4

In what routes are thiazide diuretics absorbed well in?

Answer 4

all routes

Question 5

How quickly, and how long, do responses occur when thiazide diuretics are used?

Answer 5

the response occurs 2-3 hours and lasts 6-12 hours

Question 6

What are thiazide diuretics used for?

Answer 6

antihypertensive agent, used as an adjunct, treatment of post parturient udder edema in cattle, Ca-oxalate uroliths, and nephrogenic diabetes insipidus in dogs

Question 7

What are the adverse effects and contraindications of thiazides?

Answer 7

Adverse effects - fluid and electrolyte imbalance, hypokalemia and hyperuricemia
Contraindications - hyperglycemia and glucosuria if used in diabetic and prediabetic animals

Question 8

What electrolyte imbalance is associated with prologed thiazide use?

Answer 8

hypercalcemia

Question 9

How do thiazidees produce hyperglycemia and glucosuria in diabetic and prediabetic animals?

Answer 9

they inhibit the conversion of proinsulin to insulin

Question 10

What are the types of potassium-sparing diuretics?

Answer 10

Na channel blockers and aldosterone antagonists

Question 11

What drugs are the Na channel blockers?

Answer 11

triamterene and amiloride

Question 12

What drugs are the aldosterone antagonists?

Answer 12

spironolactone and potassium canrenoate

Question 13

How do Na channel blockers work?

Answer 13

They block Na channels and reduce the luminal potential and the driving force for K secretion. They also reduce the lumen negative potential which decreases H secretion in the intercalated cells

Question 14

What is the net effect of Na channel blockers?

Answer 14

Increased Na, decreased K, decreased H

Question 15

What is the mechanism of action of aldosterone antagonists?

Answer 15

they completely inhibit the binding of aldosterone to its receptors and thereby reduce the synthesis of Aldosterone-induced proteins (AIP). Therefore, the antagonists inhibit some functions of AIP

Question 16

What AIP functions do aldosterone antagonists inhibit?

Answer 16

Synthesis of Na/K channels
Synthesis of Na/K ATPase
Mitochondrial ATP production

Question 17

What is the net effect of aldosterone antagonists?

Answer 17

increased Na, decreased K, and decreased H

Question 18

K sparing diuretics are used in combination with ____ ____ diuretics.

Answer 18

potassium losing

Question 19

In what cases are potassium sparing diuretics used in combination with potassium losing diuretics?

Answer 19

Chronic use for treatment of CHF
Treatment of aldosteronism
Treatment of ascites

Question 20

What type of drugs are carbonic anhydrase inhibitors?

Answer 20

sulfonamide derivitives

Question 21

What do carbonic anhydrase inhibitors do?

Answer 21

they inhibit carbonic anhydrase enzyme and reduce the number of hydrogen ions available for Na/H exchange

Question 22

What does carbonic anhydrase inhibitors result in?

Answer 22

Increase NaHCO3 (Na bicarbonate ) excretion
Increased K excretion 
Increased Cl retention (causes hypercholermic acidosis)

Question 23

What therapeutic uses are carbonic anhydrase inhibitors used for?

Answer 23

for glaucoma and metabolic alkalosis

Question 24

How are carbonic anhydrase inhibitors effective in treating glaucoma?

Answer 24

inhibition of ciliary body carbonic anhydrase which causes decreases aqueous humor production

Question 25

What drugs are the xanthines (methylxanthines)?

Answer 25

Aminophylline, Theophylline, caffeine, and theobromine

Question 26

What is the mechanism of action of xanthines?

Answer 26

It increases renal blood flow and increases GFR which then decreases Na reabsorption in the proximal convoluted tubule

Question 27

What are the therapeutic uses of xanthines?

Answer 27

they are rarely used soley for diuresis but increase urine output

Question 28

What urinary acidifiers did we talk about in class?

Answer 28

ammonium chloride and methionine

Question 29

What is ammonium chloride used for?

Answer 29

it is going to lower the pH of ECF and urine which eventually causes an increased Cl load in the kidney producing urinary loss of Na and Cl and mild diuresis

Question 30

What are the therapeutic uses of urinary acidifiers?

Answer 30

They promote the excretion of ionizable drugs or poisons by urinary cailcfication
Urinary stone dissolution and prevention

Question 31

What do ace inhibitors do?

Answer 31

they prevent ACE from converting angiotensin I into Angiotensin II

Question 32

What do AT1 receptor blockers do?

Answer 32

They block angiotensin II from interacting with AT1 receptors in vasculature

Question 33

What drugs are the ACE inhibitors?

Answer 33

Captopril, Enalapril, Lisinopril and others

Question 34

What drugs are AT1 receptor blockers?

Answer 34

Losartan, Irbesartan, and Valsartan

Question 35

What therapeutic uses do Ace inhibitors and AT1 receptor blockers?

Answer 35

Vasodilators in heart failure
Treatment of hypertension
Adjunctive treatment in chronic renal failure
At1 blockers reduce mortality associated with cardiac problems and may have anticancer and neuroprotective properties

Question 36

What is the Renin-Angiotensin-Aldosterone System (RAAS) a key regulator of?

Answer 36

BP, fluid volume, and electrolytes