Potassium wasting diuretics

Question 1

List the classes of K wasting diuretics

Answer 1

Carbonic anhydrase inhibitors

Loop Diuretics

Thiazides

Question 2

What are the carbonic anhydrase inhibitors

Answer 2

Acetazolamide

Dorzolamide

Question 3

How does Acetazolamide cause diuresis

Answer 3

Inhibits CA in both the lumen and inside the renal tubular cells at the PCT.

Inhibits resorption of both Na and HCO3-

Increases Na+ concentration in the lumen at collecting duct, increasing K+ excretion as well.

Causes Na, HCO3- and K+ excretion.
Diureses and metabolic acidosis.

Question 4

Indications for CA inhibitors

Answer 4

NOT typically used for HF, HTN, or diuresis

1) Glaucoma
2) Urinary alkalization in GOUT and CYTEINURIA to prevent renal stones.
3) Metabolic alkalosis
4) Urinary alkalinization to increase weak acid excretion - Aspirin, penicillin, cephalosporins, other diuretics.

5) Idiopathic intracranial hypertension
6) Meniere’s disease
7) Elevation sickness - Decreases CSF pH (causes mild intracranial acidosis) stimulating respiration.

8) Anti-epileptic. – CNS Acidosis increases the seizure threshold.

Question 5

Acetazolamide SEs

Answer 5

1 ) Hyperkalemia

Calcium Phosphate urinary stones - are increased in alkaline urine.

Sulfa drug allergy

Interstitial Nephritis!!

Increased ammonia resorption (decreased ionization of ammonium)

Question 6

Acetazolamide contraindications

Answer 6

Sulfa allergy

Pregnancy

Cirrhosis, liver insufficiency, Alkaline urine decreass ammonia excretion. (ammonium is a weak base)

Question 7

List the loop diuretics

Answer 7

Bumetanide

Furosemide

Torsemide

Ethycrynic acid

Question 8

What is the main loop diuretic used?

Answer 8

Furosemide

Ethacrynic acid only if pat has sulfa allergy

Question 9

Furosemide dose

Answer 9

20-40mg

20 mg orally for chronic use, HTN

40 mg i.v. for acute edema states.

Question 10

Furosemide indications

Answer 10

1) Pulmonary edema - life saving
2) Symptomatic, edematous heart failure
3) Edematous states associated with renal failre
4) Acute LV failure - relieves pulm edema, and also decreases preload to heart.
5) Chronic hypertension, a second line drug after thiazide diuretics or if there is HTN with renal failure
6) Chronic renal insufficiency - releives the hyperkalemia. Furosemide is the strongest drug at excreting potassium.
7) Excretion of alkaline, positively charged metals, Barium, Iodide. Doesn’t work for lithium.

Question 11

Furosemide side effects

Answer 11

OHHH DAANG She fell

Ototoxicity
Hypomagnesemia
Hypokalemia
Hypotension (Hypovolemia)

Dehydration and (Hypovolemia)
Allergic reaction and Allergic interstitial nephritis
Alkalosis (from the hypokalemia)
Nephritis
Gout

Syncope

Question 12

Thiazide drugs, list

Answer 12

Chlorothiazide - archetype

Hydrochlorthiazide and Indipamide - main currently.
Hydrochlorthiazide is the most potent uses lowest dose, and is most common.

Chlorthalidone - longest acting

Metolazone

Question 13

Thiazide mechanism

Answer 13

Inhibits the Na+Cl+ symporter in the Distal convoluted tubule

Question 14

Effects of Thiazides

Answer 14

HyperGLUC
HypoNa HypoK

Increases:
Glucose --Hypokalemia --Decreased insulin release -- hyperglycemia
Lipids, cholesterol
Uric acid
Calcium

Question 15

Thiazide indications

Answer 15

Chronic Heart Failure, after NYHA stage 2

Hypertension: especially in elderly and black patients

Osteoperosis

HypercalciURIA and Calcium kidney stones

Nephrogenic diabetes insipidus (not responsive to ADH)

Question 16

When are thiazides contraindicated to treat Nephrogenic DI?

Answer 16

When it is caused by Lithium.

Thiazides increase lithium retention and toxicity.

Question 17

Thiazide SEs

Answer 17

HyperGLUC symptoms

Ortho Hypo

Worsens diabetes

Interstitial nephritis in rare cases
They are sulfa drugs