Thiazide diuretics and related drugs

Question 1

Thazides - adm

Answer 1

Oral

Question 2

Thiazides - indications

Answer 2

Edema.
Very useful for: Diabetes insipidus, HT, nephrolithiasis.
Useful for: Cirrhosis, CHF, nephrotic syndrome, pulmonary edema, renal impairment, steroid and estrogen therapy.

Question 3

Thiazides - MOA

Answer 3

Actively secreted into the nephron by proximal tubular cells, and act on early distal tubule to inhibit Na,Cl symporter. This causes a higher concentration of NaCl in the late distal tubule, which stimulates exchange of a small amount of Na for K.

Question 4

Thiazides - effects

Answer 4

Moderate natriuretic.
Kaliuretic.
Increased Mg excretion. 
Decreased Ca excretion. 
Elevated blood glucose, uric acid, lipid levels.

Question 5

Thiazides - adverse effects

Answer 5

Hypokalemia and hypokalemic metabolic alkalosis.
Gout.
Increased cholesterol, glucose and uric acid.
Blood cell deficiencies (except indapamide)

Question 6

How do thiazides decrease Ca excretion?

Answer 6

Decreased expression of Ca transport proteins: epithelial Ca channel, calbindin, Na-Ca exchanger proteins.

Question 7

Mechanism of hypokalemic metabolic alkalosis and treatment.

Answer 7

Hypokalemia causes exchange of K and H ions between ICF and ECF. Hypokalemia also causes increased H excretion in exchange for Na. Treatment is potassium chloride for IV and oral adm.

Question 8

Why can thiazides be used for nephrogenic diabetes insipidus?

Answer 8

A paradoxical antidiuretic effect causes decreased fluid excretion. Decreased plasma volume caused by thiazides causes increased water and Na reabsoption, ultimately leading to less water in collecting ducts. Since this is where ADH exerts its effects, thiazides may cause decreased water excretion.

Question 9

Thiazides and related drugs - 4 drugs

Answer 9

Hydrochlorothiazide
Chlorothalidione
Indapamide
Metolazone

Question 10

Indapamide - effects and indications

Answer 10

Diuretic and vasodilator actions. Indicated for hypertension and heart failure.

Question 11

Thiazides - interactions

Answer 11

Potentiates effect of loop diuretics