Potassium Excreting (wasting) Diurectics

Question 1

What are the extra renal diuretics?

Answer 1

Water
Alcohol
Digitalis
Dopamine (low dose)
Colloids

Question 2

Which are the K+ excreting diuretics?

Answer 2

CAIs
Loops
Thiazides

Question 3

Name the CAIs

Answer 3

Acetazolamide
Dorzolamide
Brinzolamide

Question 4

Name the loop diuretics

Answer 4

Furosemide
Bumetanide
Torsemide
Ethacrynic acid

Question 5

What are the clinical indications of loop diuretics?

Answer 5

Acute pulmonary Edema
CHF
Refractory Edema
Acute/chronic kidney failure
Hypertension
Poisoning
Anion overdose
Hypercalcemic states

Question 6

What are the adverse effects of loop diuretics?

Answer 6

Hypokalemia
Metabolic alkalosis
Hypocalcemia
Hypomagnesemia 
Hyperuricemia
Transient deafness
Secondary hyperaldosteronism
Sulphonamide hypersensitivity
Ototoxicity

Question 7

What are the drug interactions of loops diuretics?

Answer 7

NSAIDs decrease their effect
Aminoglycosides may enhance their effect
They enhance the effects of muscle relaxants

Question 8

How are loops administered?

Answer 8

Oral

Parenteral

Question 9

What is the dose of furosemide?

Answer 9

20-40mg in the morning

Question 10

What is the dose of furosemide when the GFR <20 (kidney insufficiency)?

Answer 10

500mg

Question 11

What is the half life of loops?

Answer 11

Short half life

Question 12

What is the half life of Furosemide?

Answer 12

2-3h

Question 13

What are the pharmakinetic features of loops?

Answer 13

They act on the luminal side therefore their activity correlates with GFR

Question 14

What are the clinical uses of CAIs?

Answer 14

Glaucoma
Acute mountain sickness prophylaxis
Metabolic alkalosis
Urinary alkalisation
Severe hyperphosphatemia

Question 15

What are clinical indications of CAIs when used as adjacent therapy?

Answer 15

Epilepsy
Refractory Edema
CSF leakage

Question 16

When would we use CAIs in case of poisoning?

Why?

Answer 16

We would use CAIs when we are trying to eliminate a weak acid. E.g., aspirin poisoning

Because CAIs promote the Alkalisation of the urine which promotes the excretion of weak acids

Question 17

Why are CAIs indicated in glaucoma?

Answer 17

CA is involved in the production of aqueous humour. Therefore there is decreased AH production which reduces the IOP.

Question 18

In which type of glaucoma do we use CAIs?

Answer 18

Chronic open angle glaucoma

Question 19

How are CAIs administered?

Answer 19

Oral

IV

Question 20

How are CAIs eliminated?

Answer 20

Renal elimination - active tubular secretion + passive reabsorption

Question 21

What is the percentage of protein bound CAIs?

Answer 21

90%

Question 22

What are the extra-renal actions of CAIs?

Answer 22

Decreased production of aqueous humour
Decreased production of CSF
Decreased production of gastric and pancreatic juice

Question 23

What are the contraindications of CAIs?

Answer 23

Sulphonamide sensitivity

Severe kidney or hepatic disorders

Question 24

What are the adverse effects of CAIs?

Answer 24

Hyperchloremic metabolic acidosis
Hypokalemia 
Paresthesia
Somnolence
Renal stones (Ca-phosphate, cysteine)
Sulphonamide sensitivity

Question 25

Name the Thiazides

Answer 25

Bendroflumethiazide | Hydrochlorothiazide

Question 26

What are the clinical indications of Thiazides?

Answer 26

``` CHF Hypertension (1st line) Edema Idiopathic hypercalciuria (kidney stones) Nephrogenic diabetes insipidus Nephrolithiasis ```

Question 27

What are the adverse effects of thiazides?

Answer 27

``` Hypokalemia Hypercalcemia Hypomagnesemia Hyperuricemia Metabolic alkalosis Impaired glucose tolerance Weakness Hypersensitivity Secondary hyperaldosteronism ```

Question 28

Why is hyperuricemia an adverse effect of thiazide usage?

Answer 28

Thiazides increase serum Uric acid by decreasing acid secreted by the organic acids secretory system which can result in gout.

Question 29

Which side of the nephron do Thiazides work on?

Answer 29

The luminal side

Question 30

How is Indapamide eliminated?

Answer 30

Partly via bile

Question 31

How are thiazides administered?

Answer 31

Orally

Question 32

Do Thiazides have a longer or shorter half life?

Answer 32

Longer half life

Question 33

What is the dose of Hydrochlorothiazide in hypertension?

Answer 33

6.25-25mg

Question 34

What is the dose of Hydrochlorothiazide in CHF?

Answer 34

25-100mg

Question 35

Which CAIs can be used in epilepsy?

Answer 35

Dorzolamide | Brinzolamide

Question 36

Why do we never use CAIs alone?

Answer 36

They are very weak and tolerance develops very quickly. Use only for short term application

Question 37

Where in the nephron do CAIs act?

Answer 37

PCT

Question 38

Where in the kidney do loop diuretics work?

Answer 38

Thick ascending loop

Question 39

Where in the kidney do thiazides act?

Answer 39

Distal tubule

Question 40

How are CAIs administered in the treatment of glaucoma?

Answer 40

Topically

Question 41

Why are renal stones a side effect of CAIs use?

Answer 41

CAIs creates alkalisation of the urine. Calcium phosphate stones are more likely to form in alkaline urine.

Question 42

Which loop can we use if the patient has a sulphonamide hypersensitivity?

Answer 42

Ethacrynic acid

Question 43

Why are thiazides used in nephrolithiasis?

Answer 43

Because thiazides lower the amount of urinary calcium

Question 44

Why are calcium phosphate stones likely to form in CAI usage?

Answer 44

Because calcium phosphate stones are more likely to form in an alkaline urine

Question 45

What is the mechanism of action of loops?

Answer 45

they inhibit the sodium/potassium/2 chloride transporter

Question 46

Where do loops work?

Answer 46

thick ascending limb

Question 47

Where do CAI work?

Answer 47

PCT

Question 48

Where do thiazides work?

Answer 48

Distal nubile

Question 49

Do loops loose or reabsorb calcium?

Answer 49

Loops loose calcium

Question 50

When shouldn't loops be used and why?

Answer 50

Should not be used in osteoporosis because they loose calcium

Question 51

Do thiazides promote or decrease calcium excretion?

Answer 51

Thiazides decrease calcium excretion

Question 52

what is the effect of thiazides on on smooth muscle cells?

Answer 52

They hyperpolarize smooth muscle cells causing vasodilation

Question 53

What is the effect of thiazides on beta cells of the pancreas?

Answer 53

they decrease insulin release - hyperglycaemia

Question 54

Why do thiazides cause hyperglycaemia?

Answer 54

Because they prevent insulin release from beta cells of the pancreas

Question 55

What is the mechanism of action of thiazides?

Answer 55

they inhibit the Sodium/Cl co-transporter in the distal tubule

Question 56

What is the result of thiazide use?

Answer 56

Sodium and chloride loss

Question 57

What are thiazide drug interactions?

Answer 57

They interact with digitoxin leading to increased toxicity due to electrolyte disturbances

Question 58

When should thiazides be avoided and why?

Answer 58

In patients with DM | Because they inhibit insulin release from beta cells of the pancreas