Block 2 - Diuretic Med Chem Flashcards

1
Q

Label the corresponding diuretic and how it effects the the nephron pathology

A
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2
Q

What is the MOA of osmotic diuretics?

A

Allows water to be retained in the tubules preventing it from being reabsorbed into systemic circulation

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3
Q

What is the predominant osmotic diuretic? When is it used?

A

Mannitol (Osmitrol) is used is the hospital for trauma (head) patients usually with CNS fluid retention

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4
Q

Example of osmotic diuretics?

A

Mannitol
Sorbital
Glycerin
Isosorbide

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5
Q

MOA of carbonic anhydrase inhibitors?

A

Causes diuresis by inhibiting H+ formation -> less Na+ and H2O reabsorption

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6
Q

What are the disadvantages of using carbonic anhydrase?

A

Being the oldest diuretic class, 99% of the drug must be inhibited to be effective
Therefore, not considered first-line

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7
Q

How much of sodium is filtered by carbonic anhydrase?

A

2-5%

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8
Q

Example of carbonic anhydrase?

A

Acetazolamide (Diamox)

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9
Q

What is Acetazolamide’s indication?

A

Diamox is used to treat glaucoma by reducing the amount of aqueous humor that causes the pressure

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10
Q

How does Diamox’s structure contribute to its bioavailability and excretion?

A

Sulfonamide has a negative charge, however, lipophilic structure gives it >90% PO F and excreted unchanged

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11
Q

What is the outcome of chronic Acetazolamide use?

A

Prolonged use causes urine to become alkaline -> acidosis in blood and use is very limited

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12
Q

What functional group became the basis of popular diuretic structures?

A

Sulfonamide

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13
Q

How does thiazide structures differ from carbonic anyhydrase?

A

Contain disulfonamide analogues

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14
Q

What increases thiazide activity?

A

Chloro and amino substitutions causes acetylation of amino groups causing ring closure

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15
Q

What is the MOA of benzothiadiazines?

A

Inhibits Na+/Cl- transporter in the DCT -> Inhibits Na+ reabsorption (saluretic)

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16
Q

What is the main diurectics indicated for HTN?

A

Thiazides

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17
Q

Describe the thiazides SAR?

A
  1. Benzothiadiazide-1,1-dioxide is essential
  2. Sulfonamide @C7 is essential for activity
  3. EWG @C6 greatly enhances activity (EDG reduces)
  4. 3,4-dihydro derivative enhance activity 10-fold
  5. Lipophilic group @C3 increases DOA
  6. Alkyl substitution @N2
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18
Q

Chlorothiazide? F? t1/2? DOA? Metabolism?

A
  1. Diuril is least potent and simplest thiazide
  2. Low F
  3. 1-2hrs
  4. 6-12hrs
  5. Unchanged urinary excretion
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19
Q

Hydrochlorothiazide? F? t1/2? DOA? Metabolism?

A
  1. HydroDiuril has medium potency
  2. High F
  3. 6-15hrs
  4. 6-12 hrs
  5. Unchanged urinary excretion

Most popular diuretic for HTN

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20
Q

Trichloromethiazide? DOA? Metabolism?

A

Diurese is one of the most potent thiazide
DOA: 24 hrs
Metabolism: Unchanged urinary excretion

21
Q

Methyclothiazide? DOA? Metabolism?

A

Enduron, Aquatensen is one of the most potent thiazide
DOA: 24 hrs
Metabolism: Unchanged urinary excretion

22
Q

Polythiazide? DOA? Metabolism?

A

Renese is one of the most potent thiazide
DOA: 24-48 hrs
Metabolism: Unchanged urinary excretion

23
Q

Hydroflumethiazide? F? t1/2? DOA? Metabolism?

A

Saluron has a low potency
t1/2: 17 hrs
DOA: 18-24 hr
Metabolism: unchanged urinary excretion

24
Q

What is the most dangerous ADR of diuretics?

A

Hypokalemia

25
Q

Bendroflumethizide? F? T1/2? DOA? Metabolism?

A

Naturein is a potent thiazide
F: 90% due to lipophilicity
t1/2: 8-9 hrs
DOA: 6-12 hrs
Metabolism: unchanged urinary excretion

26
Q

ADRS of thiazide? How do you prevent them?

A
  1. Hypokalemia, thiazides are usually administered with K+ supplements
  2. Hypochloremia, hypoatremia, hypercalcemia, hyperuricemia, supplements and gout meds are given
27
Q

Long term use leads to what kind of ADRs?

A

glucose intolerance and/or increased blood lipids

28
Q

Characteristics of loop diuretics?

A
  1. High-ceiling (more potent=more diuresis)
  2. Sulfonamide derivatives
29
Q

Describe loops site of action? Onset? DOA?

A
  1. thick ascending limb of the loop of Henle
  2. Quick onset
  3. Short DOA
30
Q

Loop diuretic MOA?

A
  1. Diuresis effect by inhibiting Na+/K+/2Cl-
  2. Prevents ion from being reabsorbed in ascending portion that doesn’t allow water to be reabsorbed -> more diuresis
31
Q

ADRs of loops?

A

Hypokalemia and hypocalcemia

32
Q

Furosemide? Onset? DOA? Excretion?

A

Lasix is more acidic than thiazide (carboxylate), 8-10 fold more potent than thiazides
Onset: 30 min
DOA: 6-8 hr
Metabolism: Primarily excreted unchanged

33
Q

What is Lasix primarily used for?

A

Furosemide: CHF, renal/hepatic edema, other edemas not primarily for HTN

34
Q

How does bumetanide differ from lasix structurally? How does this benefit?

A
  1. 4-Cl has been replaced by 4-phenoxy
  2. 6 amino has been moved to 5-amino
    Bumedex’s structural changes leads to 50x more potency than lasix
35
Q

What is the indications for torsemide? Onset? DOA?

A

Demadex is indicated for CHF and some HTN
1. Sulfonamide is changed to sulfonylurea
Onset: 1-2 hrs
DOA: 6 hrs

36
Q

How does ethacrynic acid differ from other loop diuretics?

A
  1. Edecrin is a phenoxyacetic acid derivative
  2. Sulfhydryl enzymes allows solute reabsorption, however Edecrin (olefin) covalently binds to enzymes disengaging it
37
Q

What is the MOAs of Edecrin?

A
  1. Sulfhydryl inhibitor
  2. Olefin reduction -> diuresis
38
Q

What is potassium sparing diuretics? MOA?

A

Aldosterone antagonist that inhibits it from promoting K+ excretion and Na+/Cl- reabsorption

39
Q

What are the dangers of diuretics other than K+-sparing?

A

K+ wasting leading to hypokalemia which can be fatal

40
Q

What is spironolactone’s indication? Binding? ADR?

A

Aldactone
Edema from cirrhosis given concurrently with K+ wasters

Produrg that binds to aldosterone receptors once activated

41
Q

ADRs of Aldactone?

A

Hyperkalemia
Decreased libido and impotence

42
Q

How is ALDACTONE metabolized?

A

Prodrug (Aldactone) -> Canrenone

42
Q

What is eplerenone? Indication? t1/2? Metabolism?

A

HTN and CHF
t1/2: 5-6 hrs
Its lipophilicity requires more metabolism therefore, it undergoes extensive metabolized to inactive metabolites

42
Q

What are other K+ sparing diuretics? ADRs?

A
  1. Epithelial sodium channel inhibitors
  2. Non-aldosterone based drugs
43
Q

Triamterine? Class? t1/2? Metabolism?

A

Dyrenium, Dyazide
Class: triame, Blocks Na/K channel
t1/2: 2h
Metabolism: 4-hydroxytriamterine (inactive)

43
Q

Amiloride? Class? t1/2? Metabolism? Structure?

A

Midamor
Class: diamine guanidine, block Na/K channel
t1/2: 6-10 h
Metabolism: excreted unchanged

44
Q

What are the general MOAs of K+ sparing diuretics? ADRs?

A

Blocks Na+ reabsorption

Hyponatremia and hypocalcemia

45
Q

What is the epithelial sodium channel MOA?

A

No K+ is allowed to be excreted