Diuretics

Diuretics

DIURETICS

INDUCE DIURESIS -- > INCREASE URINE VOLUME

Classification

1. Acetic anhydride inhibitor 
2. Osmotic Diuretics
3. Potassium sparing diuretics
4. Loop diuretics 
5. Thiazides

DRUGS CLASSIFICATION 

1. Acetic Anhydrase Inhibitor (AAI)
eg. ACETAZOLAMIDE

- weak diuretics.
- Act on PCT (proximal convoluted tubule).
- it increases NAHCO3 excretion, making your urine alkaline & salty.
- INCREASE NA/H20 EXCRETION.

“ACID”azolamide causes ACIDosis.

USES

Mnemonics ''GUMA''

• Glaucoma 
• Urinary alkalizer 
• Metabolic alkalosis 
• Prophylaxis of mountain sickness 

A/E
Mnemonics ''ACID MANS''
- hypercholemia metabolic acidosis
- neuropathy (due to increase seizure threshold)
- ammonia toxicity (ammonia reabsorption -->hepatic encephalopathy)
- sulfa allergy (renal damage, crystalluria, rash, blood dysrasia)


But if you’re allergic to sulfur, then you better adjust your doses. Don’t take too much since it could cause hyperchloremic metabolic acidosis.


2. OSMOTIC DIURETICS:
it targets your PCT, makes you pee, and increases fluid osmolarity.

Mnemonic ''GUM''

• Glycerol
• Urea
• Mannitol

MANNITOL

Uses: '' BCGS''
B- Barturate Poisoning
C- Cerebral Edema
G- Glaucoma
S- Stroke /Shock

C/I : ''CAP'

• If cerebral hemorrphage --> C/I ( as Mannitol can escape from hemorrphagic vessels & cause dehydration of brain cells via osmotic action) 
• Pulmonary edema 
• anuria ??? 
• CHF (it causes tachycardia) 

*** If you have CHF or Anuria, DON’T take mannitol if you know whats good for ya!


3. THIAZIDE DIURETICS
Hydrochlorothiazides
Chlorothiazides

THIAZIDE - 1ST DOC for HYPERTENSION.

• MoA - Act on DCT (distal convoluted tubules).
• Increase Na, K, Cl, H20 excretion.
• Increase Calcium reabsorption. 

Thiazide diuretics use (4) MNEMONIC ''HE IS DOCTOR'' - DOC FIRST IN HTN^^

• HTN
• CHF
• idiopathic hypercalcuria
• nephrogenic diabetes insipidus
• Generalised Edema 

SE of thiazide diuretics (4)
HyperGLUC

• glycemia
• lipidemia
• uricemia
• calcemia

C/I THIAZIDES = diabetes, dyslipidemia, gout, young patients




4. LOOP DIURETICS

• ethacrynic acid
• furosemide
• bumetanide
• torsemide

(most effective diuretics)

What is different about ethcyrnic acid compared to the other loop diuretics ???(important)

it is not a sulfonamide thus it can be used when a pt has a sulfa allergy
If you are allergic to sulfur yet edematous & want to live, take ethacrynic acid instead cause its a phenoxyacetic acid derivative.

Loop diuretics use (3)

• Edema (CHF, cirrhosis, nephrotic syndrome)
• HTN
• hypercalcemia

Loop diuretics SE (6)(mnemonic) OH DANG
O -ototoxicity
H- hypokalemia
D- dehydration
A - sulfa allergy
N -nephritis (interstitial)
G- gout


D/I
Mnemonics ''L and D''
L = Lithium - decreased clearance

A = Aminoglycosides ( due to ototoxicity)

D = Digitalis (due to hypokalemia)


5. POTASSIUM SPARING DIURETICS

increase excretion of Na, Cl, H20 but RETAIN POTASSIUM K. 

(mnemonic) K+ STAys
Spironolactone
triamterene
amiloride

2 different MoA (depends on locations)
- Disted Convoluted Tubule (DCT) --> Triamterene, Amiloride . 

-Collecting Tubule(CT) --> spironolactone

Treatment

• - hypertension often combination with thiazide diuretics or loop diuretics. 
• - hypoaldosteronism. 

SE (2)

• hyperaldosteronism
• hyperkalemia 
• gynecomastia (via an antiandrogen effect)

classification mnemonic

Diuretics Classification in Order of Site of Action

Pharmacology/Renal

COLT Pee

Sequential site of action along the nephron
Carbonic anhydrase inhibitors (at the proximal tubule)
Osmotic diuretics (at the Loop of Henle)
Loop diuretics (at the ascending loop)
Thiazides (at the distal tubule)

Potassium-sparing diuretics (at the collecting tubules)

Terrminology

Bicarbonate Diuretic:
                                 A diuretic that selectively increases sodium bicarbonate excretion. Example: a carbonic anhydrase inhibitor.
 Diluting segment:
                                   segment of the nephron that removes solute without water; the thick ascending limb and the distal convoluted tubule are active salt-absorbing segment that are not permeable by water.
Hyperchloremic metabolic acidosis:
                                                 A shift in body electrolyte and pH balance involving elevated chloride, diminishes bicarbonate concentration , and adecrease in pH in the blood.Typical result of bicarbonate diuresis.
Hypokalemic metabolic alkalosis:
                                              A shift in body electrolyte and pH involving a decrease in serum potassium and increase in blood pH.Typical  result of loop and thiazide diuretic actions.
nephrogenic diabetes insipidus:
                                             Loss of urine-concentrating ability in the kidney caused by lack of responsiveness to antidiuretic hormone (ADH is normal or high).
Pituitary diabetes insipidus:
                                       Loss of urine-concentrating ability in the kidney caused by lack of antidiuretic hormone (ADH is low or absent).
Potassium-sparing diuretic:
                                       A diuretic that reduces the exchange of potassium for sodium in the collecting tubule; a drug that increases sodium and reduces potassium excretion.Example: aldosterone antagonists.
Uricosuric diuretic:
                           A diuretic that increases uric acid excretion , usually by inhibiting uric acid reabsorption in the proximal tubule. Example: ethacrynic acid.        

Introduction

Diuretics:

               are useful in treatment of a variety of diseases associated with abnormal retention of salt and water in the extracellular compartment of body,commonly referred to as edema .In general a diuretic is an agent that increases the rate of urine excretion by the kidneys,primarily through decreased tubular re_absorption of sodium ions and its osmotic equivalent of water in the renal tubules.Excessive fluid accumulation in the extracellular compartments may be due to cardiac failure, cirrhosis of liver, or renal disorders.

classification:

                                      1. Osmotic diuretics
                                      2. Mercurial diuretics
                                      3. Sulfonamide diuretics
                                           a). Carbonic anhydrase inhibitors
                                           b). Benzothiadiazines
                                           c). Miscellaneous (chlorthalidone)
                                      4. Purine pyrimidine diuretics (Xanthines)
                                      5. Loop diuretics

mercurial diuretics

Organic mercurial diuretics

Organic mercurial diuretics