Diuretics || Classification || ONI

What are diuretics  ?

Diuretics are a class of drug which promotes the increase urine production from kidney by excretion of sodium and chloride. 

Diuretics are also known as water pills and most commonly used in the treatment of high blood pressure

Classification /  Types of diuretics

The diuretics drugs having different classes and subdivided in different types these are as following. 

1.High efficacy diuretics

• Furosemide
• Bumetanide
• Torasemide

2.Medium efficacy diuretics

(A) Benzothiadiazines

• Hydrochlorothiazide
• Benzothiazide
• Hydroflumethiazide
• Clopomide

(B) Thiazides

• Chlorthalidone
• Metolazone
• Xipamide

3.Low efficacy diuretics

(A) Potassium sparing diuretics

• Triomterene
• Amiloride
• Spironolactone

(B) Carbonic anhydrase inhibitor

• Acetazolamide
• Methazolamide

(C) Osmotic diuretics

• Mannitol
• Isosorbide glycerol

Mechanism of action of diuretics

The different types of diuretics has different mechanism of action as following......... 

(A) Mechanism of action of loop diuretics

Loop diuretics are act on ascending limb of loop of henle which reduce the absorption of electrolyte. 

It is greatly increase the excretion of sodium and chloride in the urine results in increase urine out put. 

A loop diuretic furosemide is also a weak carbonic anhydrase inhibitor. It increase excretion of bicarbonate and phosphate. 

(B) Mechanism of action of thiazides diuretics

Thiazides are a class of drug that act  on early distal tubule. 

This class of drugs block sodium and chloride symporter symptoms in early distal tubule. 

They can also inhibit carbonic anhydrase activity and increase bicarbonate loss. 

Thiazides also enhance excretion of magnesium and potassium but they inhibit urinary excretion of calcium and uric acid resulting in hypercalcemia and hyperuricemia. 

(C) Mechanism of action of potassium sparing diuretics

The potassium sparing diuretics are the class of drugs of diuretics which inhibit the potassium excretion in urine and increase sodium and water in the urine. 

(D) Mechanism of action of carbonic anhydrase

Carbonic anhydrase is a class of diuretics which suppress the activity of carbonic anhydrase enzyme. 

Carbonic anhydrase is the enzyme which present in renal tubular cell, gastric mucosa, exocrine pancreas, ciliary body of eye, brain and RBC. 

It works on proximal tubules of the kidney the enzyme carbonic anhydrase is inhibit. It does not allowing the reabsorption of HCO3, sodium, chloride, so by inhibiting this enzyme, these ion are excreted along with excess water. 

(E) Mechanism of action of Osmotic diuretics

An Osmotic diuretics is class of drug of diuretics that inhibits reabsorption of water and sodium. 

It elevates blood plasma osmolarity, resulting in enhanced flow of water from tissue including the brain and CSF into interstitial fluid and plasma. 

Diuretics like mannitol induced diuresis because it does not reabsorb in renal tubules, their by increase the osmolarity of glomerular filtrate and facilitating excretion of water and inhibiting the renal tubular reabsorption of sodium, chloride. 

Uses / Indication of diuretics

The uses / indication of diuretics are different according to their drugs classes because different drug of class have different mechanism of action that is following............... 

(A) Uses of Loop diuretics

• Cirrhosis (chronic liver damage) 
• Hypertension (High blood pressure) 
• Renal failure
• Nephrotic syndrome (group of symptoms due to kidney damage) 
• Renal transplant
• Edema (cerebral edema, pulmonary edema) 
• Chronic kidney disease
• Heart failure
• Ascites (accumulation of fluid) 

(B) Uses of Thiazide diuretics

• Diabetes insipidus (passage of large volume of dilute urine.) 
• Urine stones (deposition of minerals, salt, calcium in kidney) 
• Heart failure (unable to function well) 
• Osteoporosis (weakness of the bone) 
• Hypercalcemia (increase level of calcium) 
• Bromine intoxication (high level of bromide) 
• Dent's disease (renal tubular disorder) 
• Edema (accumulation of fluid) 

(C) Uses of Potassium sparing diuretics 

• High blood pressure
• Edema related to cirrhosis of liver
• Hypokalemia (low level of potassium) 
• Heart failure
• Cirrhosis of liver

(D) Uses of Carbonic anhydrase 

• Glaucoma (damaged eye optic nerve) 
• Drug induced edema
• Congestive heart failure
• Altitude sickness (acute mountain sickness) 
• Epilepsy (petit mal unlocalize seizures) 
• Pseudotumor cerebri (idiopathic intracranial hypertension) 
• Hypertension (high blood pressure) 

(E) Uses of Osmotic diuretics

• To maintain volume and prevent oliguria 
• Reduce intra cranial pressure
• Reduce intra occular pressure 
• Anuria (passage of urine less then 100 milliliters) 

Adverse side effect of diuretics

According to classes of diuretics the adverse side effects of diuretics are............ 

(A) Adverse side effects of Loop diuretics

• Dizziness
• Hypokalemia 
• Hypomagnesemia
• Postural hypertension
• Dyslipidemia
• Ecg abnormalities
• Nausea
• Vomiting
• Thrombocytopenia
• Metabolic acidosis
• Ototoxicity
• Arrhythmia
• Hyperuricemia
• Muscle cramps
• Dehydration
• Hypotension
• Azotemia 

(B) Adverse side effects of Thiazide

• Hypokalemia
• Hyperlipidemia
• Hypovolemia
• Hypotension
• Hyponatremia
• Metabolic alkalosis
• Sulfonamide allergy
• Blurred vision 
• Skin senstivity to sunlight
• Hyperglycemia
• Loss of appetite
• Hypercholesterolemia
• Lightheadedness
• Hyperuricemia
• Stomach upset

(C) Adverse side effects of  Potassium sparing diuretics

• Hyperkalemia
• Gynecomastia
• Peptic ulcer
• Metabolic acidosis
• Tummy ache or cramp
• Blue urine color
• Tiredness
• Dry mouth
• Drowsiness
• Breast pain
• Muscle cramps
• Ataxia
• High cholestrol
• Liver disease
• Weakness
• Arrhythmia
• Irregular menstrual periods
• Confusion
• Anaphylaxis

(D) Adverse side effects of carbonic anhydrase

• Lightheadedness
• Nausea and vomiting
• Change in taste
• Hypokalemia
• Hearing loss
• Metabolic acidosis
• Diarrhoea
• Numbness
• Confusion
• Tinnitus
• Hematuria
• Headache
• Painful urination
• Tingling
• Tiredness

(E) Adverse side effects of Osmotic diuretics

• Azotemia
• Chest pain
• Confusion
• Congestive heart failure
• Erythema
• Hypotension
• Headache
• Cardiac arrest
• Dizziness
• Pruritus
• Chills
• Rhinitis
• Convulsion
• Urinary retention
• Pulmonary edema
• Nausea and vomiting
• Information of vein
• Acidosis
• Asthenia
• Fever

What is common diuretics? 

The most common diuretics are metolazone, chlorthalidone, hydrochlorothiazide which your doctor commonly used to treat various disease condition. 

What is the best diuretics for edema? 

Furosemide is concerned as a best diuretics for edema which is loop diuretics. It increase the excretion of fluid volume by increase excretion of sodium. 

What is the best diuretics for high blood pressure? 

If you have a condition of high blood pressure then you need to take thiazides diuretics because it considered as a best diuretics for high blood pressure. It act by blocking sodium and chloride channel in early distal tube. 

See Also

• Antihypertensive drugs with mnemonic
• Antiarrhythmic drugs with mnemonic
• Antianginal drugs with mnemonic

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