Diuertic Agents

Question 1

Mention the classifications of diuertics

Answer 1

A_
1_loop diuertics «thick ascending part of loop of henele»
2_Thiazide diuertics «early distal c. t»
3_ptassium sparing d«late distal c.t»
4_carbon anhydrase inhibitor «proximal c.t»
5_osmotic diuertics «more than one site»

B-
1_high efficacy d; loop
2_medium efficacy; thiazide
3_week/adjunctive; potassium sparing, carbon anhydrase inhibitors, osmotic diuertics.

Question 2

Mention the uses of loop diuertics

Answer 2

1_odema, hypertension in emergency
2_CCF
3_CRF/ARF
4_Nephrotic syndrome 
5_Hyperkalemia
6_Hypercalcemia 
7_Acute pulmonary edema
8_chemical intoxication 
9_in ptn becomes refractory to thiazide diuertics.

Question 3

How dose loop diuertics work?

Answer 3

1_inhibition of Na, K, Cl cotransporter in thick ascending loop of henle
2_same action in macula densa cells increasing GFR
3_Increased GFR lead to PGE synthesis«vesodilatation»

Question 4

what are the side effect of loop diuertics?

contraindications?

Answer 4

1_hypokalemia, hyponatremia, hypomagnesaemia
2_Acute hypovolemia, hypotension, arrythmia
3_hyperglacymia, hyperurecmia
4_GIT, CNS distubance «vomiting, headache, impotence»
5_vertigo, hearing deficits «with ethacrynic acid»
6-metabolic alkalosis

documented hypersensitivity, severe hypovolemia, hypotension, severe electrolyte imbalance, hepatic failure with impending encephalopathy

Question 5

Mention the properties of fursamide

Answer 5

1_rapid, short acting«3_6 h», massive diueresis
2_given I. v 2_5 min, I. m10_20 m, orally 20_40 m
3_I. v has a vasodilator action so use in PE, LVF
4_I. v lowers preload even before diueresis set in
5_NSAIDS decrease its effect, increase nephrotoxicity
6_Ototoxicity enhanced with aminoglycosides, vencomycin

Question 6

what are loop diuertics

Answer 6

furosemide, torsemide, bumetanide, ethacrynic acid

Question 7

what are thiazide diuertics?

Answer 7

1_chlorthalidone(thalitone) 
2_hydrochlorothiazide«microzide» 
3_Indapamide
4_metolazone«zaroxolyn» 
last two are thiazide like diuertics, effective with impaired renal function

Question 8

What is the difference between thiazide and loop diuertics?

Answer 8

loop: more effectious, كلما زادت الجرعة زاد الافكت.
Thiazide: longer durationof action, more safe in general, but more severe side effect in long use.

Question 9

explain the pharmalogical effect of Thiazide diuertics

Answer 9

1_initial reduction of BP due to decreased ECV and CO
2_sustained reduction of bp due to reduced vascular resistance
3_ECV remains modestly reduced but CO returns to pretreatment level
*hypokalemia produced varies in dose&ptn

Question 10

Mention the adverse effects of thiazide and why dose it induce hyperurecemia

Answer 10

hypokalemia, hypomagneseamia hypercalcemia, hyperurecemia, reduce GFR.

by to causes:
1_competition with uric acid for secretion by proximal tubules, leading to diminished uric acid excretion.
2_reduced ECV elevate serum uric acid

Question 11

Mention the clinical use of thiazide diuertics

Answer 11

1_Life long antihypertensive
2_mild heart f
3_severe resistance odema «metolazone with loop diuertics»
4_to prevent recurrent stone formation in idiopathic hyperclaciuria.
5_Nephrogenic diabetes insipidus

Question 12

explain how thiazide is used in treatment of diabetes insipidus

Answer 12

1_urine osmolality increase when Na transport in D. C. T is inhibited
2_reabsorption of glomerular filtrate is increased from P. C. T because of reduced GFR
3_thiazide improve AQP2 expression in collecting duct.

Question 13

Mention the uses and side effects of carbonic anhydrase inhibitors

Answer 13

Uses: in glucoma«reduce aqueous humor formation».
prevent or treat mountain sickness.

side eefect: 
1_Metabolic acidosis, Na&K wasting
2_Drowsiness, parasthesia 
3_fatigue, CNS depression
4_Renal stone formation
5_hepatic encephalopathy

Question 14

How dose potassium sparing diuertics exert its effect?

Answer 14

It’s an analogue for aldosterone, acting as competitive inhibitor to it, decrease Na conductance, block apical membrane Na channel, abolish electrical gradient for K secretion

Question 15

Mention the uses of potassium sparing diuertics

Answer 15

1_All (spironolactone, triamterene, amiloride» used as adjuvent to loop and thiazide diuertics to prevent K loss; patients requiring digoxin or amiodarone.
2_Hypokalemia
3_Spironolactone used for:
*primary hyperaldosteronism«conns syn»
*edoma in patients with: HF for Na retention
liver cirrhosis with acitise
Nephrotic syndrome
refractory edema.
*severe HF; to increase survival, reduce need for hospitalization

Question 16

Mention the adverse effects of potassium sparing diuertics

Answer 16

1_hyperkalemia 
2_CNS effects(drowsiness, confusion) 
*for spironolactone: 
3_hirsutism
4_Gyneacomastia
5_Impotence 
6_Aggravate peptic alcer

Question 17

Explain the mechanism of action for mannitol, and its characteristics

Answer 17

mechanism:
1_reduce water and Na reabsorption from proximal tubules
2_reduce water reabsorption from thin descending limb of henel loop
3_increase renal blood flow and washout of medullary tonicity (decrease function of collecting duct).

charecter: don’t interact with receptors.
don’t block renal transport

Question 18

Mention the uses of mannitol

Answer 18

1_short term treatment of acute glucoma
2_elevated intracranial pressure by cerebral edema or neurosurgery
3_poisining with bromide, barbiturates, salicylate, other drugs.
4_severe trauma and surgical procedures to reduce the buildup of toxic waste products.