Diuretics

Diuretics

Diuretics are substances or drugs that can increase diuresis, or increase urination. Some time Diuretic also caused forced diuresis. Diuretics sometimes also known as water pills. Water pills or Diuretic are designed in such a way that they are able to excrete Salts and water from The body. 

Diuretics may be used to decrease blood pressure in hypertensive patients as they are first line treatment for that condition.

Also used for CHF (congestive heart Failure) im that condition water start accumulated in body result in Edema diuretics are used for the treatment of edemic condition

 

Types Of Diuretic

• Thiazide Diuretics
• Loop Diuretics
• Potassium Sparing Diuretics
• Carbonil Anhydrase Inhibitor
• Osmotic Diuretics

diuretics

Thiazide Diuretics

Drugs included in Thiazide Diuretics are as follow:

• Chlorothiazide
• Chlorthalidone
• Indapamide
• Metolazone
• Hydrochlorothiazide

Thiazide Diuretics decreased blood pressure at same time of extra body fluid from the body. It can used to treat severe Edema with minimal side effect. Hydrochlorothiazide are newer class which can mainly used now a days.

Mechanism of Action

The thiazide derivatives act mainly in the distal tubule to decrease the reabsorption of Na+ apparently by inhibition of a Na+/Cl cotransporter on the luminal membrane of the distal convoluted tubule. They have a lesser effect in the proximal tubule. As a result, these drugs increase the concentration of Na+and Cl-

 in the tubular fluid. The acid-base balance is not usually affected. [Note: Because the site of action of the thiazide derivatives is on the luminal membrane, these drugs must be excreted into the tubular lumen to be effective. Therefore, with decreased renal function, thiazide diuretics lose efficacy.]

Therapeutic Uses

Hypertension: Clinically, the thiazides have long been the mainstay of antihypertensive medication,
because they are inexpensive, convenient to administer, and well tolerated. They are effective in reducingsa systolicnd diastolic blood pressure for extended periods in the majority of patients with mild to moderatee essentialhypertension After 3 to 7 days oft treatment the blood pressure stabilizes at a lower level and can be maintained indefinitely by a daily
Many patients can be continued for years on the thiazides alone, although a small percentage of patientsr requireadditional medication, such as β-adrenergic blockers.

Heart failure: Thiazides can be the diuretic of choice in reducing extracellular volume in mild to moderate
heart failure. If the thiazide fails, loop diuretics may be useful.

Hypercalciuria: The thiazides can be useful in treating idiopathic hypercalciuria, because they inhibitu urinaryCa2+ excretion. This is particularly beneficial for patients with calcium oxalate stones in the urinary tract



Pharmacokinetics
 The drugs are effective orally. Most thiazides take 1 to 3 weeks to produce a stabler reductionin blood pressure, and they exhibit a prolonged biologic half-life (40 hours).

Loop Diuretics

Drugs included in loop Diuretic are as follow

• Furosemide
• Toresmide
• Bumetanide

 Loop Diuretic has major action on Ascending loop of henle.  Compared to all other classes of diuretics, these drugs have the highest efficacy in mobilizing Na+ and Cl from the body.

Mechanism of action 
 Loop diuretics inhibit the cotransport of Na+/K+/2Cl-i inthe luminal membrane in the
ascending limb of the loop of Henle. Therefore, reabsorption of these ions is decreased. The loopd diureticsare the most efficacious of the diuretic drugs, because the ascending limb accounts for ther reabsorptionof 25 to 30 percent of filtered NaCl and downstream sites are not able to compensate for this increasedN l load

Therapeutic uses 
The loop diuretics are the drugs of choice for reducing the acute pulmonary edema of heartf failure Because of their rapid onset of action, particularly when given intravenously, the drugs are useful in
emergency situations, such as acute pulmonary edema, which calls for a rapid, intense diuresis. Loop diuretics( along with hydration) are also useful in treating hypercalcemia, because they stimulate tubular Ca2+ excretion.Theyalso are useful in the treatment of hyperkalemia.

Pharmacokinetics
Loopd are administered orally or parenterally. Their duration of action is relatively brief”2 to 4 hours. They are secreted into the urine.

Potassium Sparing Diuretics

Drugs included in potassium Sparing Diuretics are as follow

• Amiloride
• Spironolactone
• Triamterene

 Potassium-sparing diuretics act in the collecting tubule to inhibit Na+reabsorption and K+excretion .Potassium-sparingdiuretics are used alone primarily when aldosterone is present in excess. The major use of
potassium-sparing agents is in the treatment of hypertension, most often in combination with a thiazide

Therapeutic uses:
Diuretic: Although spironolactone has a low efficacy in mobilizing Na+ from the body in comparison with the otherdrugs, it has the useful property of causing the retention of K+Because of this latter action,
spironolactone is often given in conjunction with a thiazide or loop diuretic to prevent the K+
 excretion thatwo would otherwise occur with these drugs. It is the diuretic of choice in patients with hepatic cirrhosis.

Secondary hyperaldosteronism: Spironolactone is the only potassium-sparing diuretic that is routinely usedl Aloneto induce a net negative salt balance. It is particularly effective in clinical situations associated with secondary hyperaldosteronism.