Which diuretics is best for hypertensoin?

1Role of thiazide diuretics in hypertensoin
2Adverse affect of thiazide
3How loop diuretics can use as a treatment option in severe type of hypertension
4Indication of using loop diuretics

Hydrochlorothiazide is the most widely used diuretic for hypertension.

Diuretics drug can be in a great use for the treatment of  hypertensive patient. There are different type of diuretics. Each one of them have their specific mode of action and benefit, as well as sideffect.

But in deep analysis there is found that thiazide and thiazide like diuretics are the best for hypertensive patient. But in severe hypertension loop diuretics are the preferred one. Loop diuretics can control blood pressure  within a minute. now Let’s discuss them briefly-

Thiazide and thiazide diuretics (hydrochlorothiazide) are commonly used in the treatment of hypertensive patient.

Thiazide diuretics use as a first line antihypertensive, because

1. It has prolonged duration of action (roughly 10-12 hours)

2. Onset of action is slow therefore there is no need of close monitoring.

3. Low dose required to control hypertensive condition

4. Long-standing thiazide therapy decreases responsiveness of blood vessel to circulatory catecholamines( epinephrine ,norepinephrine)

5. Thiazide causes diuresis without changing acid base balance in internal body fluid.

6. it does not induce postural hypotension.

7. Does not cause reflex tachycardia.

Indication of thiazide diuretics:


-heart failure

-nephrolithiasis due to idiopathic hypercalciuria, -nephrogenic diabetes insipidus.

Role of thiazide diuretics in hypertensoin:

1. First, diuretics lower blood pressure by decreasing blood volume and cardiac output. Subsequent diuretics lower blood pressure primarily by reducing sodium stores in body fluids.
2. The diuretic and mild vasodilatory effects of thiazides are useful in the treatment of nearly all patients with essential hypertension.
3. Hydrochlorothiazide is the most commonly used diuretic for hypertension, but chlorthalidone has a much longer half-life and may be more effective. Therefore, the use of these two diuretics depends entirely on the patient’s condition

There is debate as to whether thiazides should be used as initial treatment for hypertension. Their moderate efficacy may limit their use as monotherapy.

Adverse affect of thiazide:

1.Hypokalemia: Hypokalemia is the most frequent problem encountered with the thiazide diuretics. It occour by following mechanisum-

Thiazide diuretics inhibit Na+ reabsorption in the early part of distal convulated tubule> Then it increased Na+ delivery to the collecting duct> This stimulates aldosterone secretion (for the purpose of Na+ reabsorption)> Increased Na+ reabsorption at the collecting duct in exchange of increased K+ excretion by Na+-K+ ion pump by the action of aldosterone.



4.Metabolic alkalosis.

5.Hyperuricemia (precipitation of gout)- Thiazide diuretics are actively secreted by acid transporter protein at the proximal convoluted tubule so, inhibit Uric acid secretion at proximal convoluted tubule which leads to hyperuricaemia and gout.

6.Hyperglycemia- Thiazides administration >cause Hypokalaemia >increase k+ concentration into B cell of pancreas > It inhibit depolarization inside B cell> decrese calcium ion transport into B cell through voltage-gated calcium channel> decrese insulin realse > eventully leads to hyperglycemia

There is another mechanism how thiazide administration cause hyperglycaemia> it diminished tissue utilization of glucose >cause Hyperglycaemia.

7.Hyperlipidemia (5-15% increase in serum cholesterol as well as increased LDL).

8. Hypersensitivity

Contraindications of thiazide:

Excessive use of any diuretic is dangerous in hepatic cirrhosis, borderline renal failure.

Now we discuss how loop diuretics can use as a treatment option in severe type of hypertension:

 Loop diuretics are also called High ceiling diuretics because  with icrease of dose it also increase its diuretic property. They are very potent and can cause up to 25% of filtered sodium to be excreted. And their action impairs the powerful urine concentrating mechanism (Na+ -K+-2CI- transporter) of the loop of Henle and confers higher efficacy compared to other diuretics  That’s the reason why Loop diuretics are also called high ceiling diuretics. Example of loop diuretics as we know are:

 1. Frusemide / Furosemide

 2. Torsemide

 3. Bumetanide

 4. Ethacrynic acid

Indication of using loop diuretics in different medical condition of a patient:

1. Heart failure causing acute pulmonary edema and other edematous diseases: Frusemide reduces fluid accumulation that causes edema, especially in the lungs. Reducing pulmonary vascular congestion, diuretics improve oxygen supply and therefore myocardial function. Reducing preload reduces the size of the heart, allowing it to work more efficiently.
2. When treating acute hypercalcemia: Hypercalcemia is usually considered a medical emergency. In this case, a patient suffering from acute hypercalcemia can use loop diuretics to reduce her Ca2+ reabsorption. In particular, loop diuretics are very effective and can affect Ca2+ diuresis. To maintain effective Ca2+ diuresis, saline must be administered concurrently with loop diuretics.
3. Hyperkalemia: Loop diuretics can significantly increase the excretion of K* in the urine. 4. Acute renal failure: Loop diuretics can increase urine output and increase K+ excretion in acute renal failure. However, kidney failure cannot be prevented.
5. Anion overload: Loop diuretics help treat toxic bromide, fluoride, and iodide ingestion by inhibiting reabsorption in the thick ascending limb. That is, if we classify the main indications for the use of loop diuretics. Inshort if you can divied the most important indications for the use of the loop diuretics  then thy include-

> Acute pulmonary edema

> Other edematous conditions

Adverse effects of frusemide:

 1. Hypovolemia (in case of massive Intravenous fluid administration)

 2. Hypokalaemia:  Hypokalemia and Hypokalemic Metabolic Alkalosis after frusemide administration.

 3. Hypokalemic metabolic alkalosis.

 4. Reversible ototoxicity (due to inhibition of symport mechanism in the endolymph)

5. Hypomagnesaemia

 1. Hypocalcaemia

 2. Hyperuricemia (leading to gout attack): Gout can be occure after frusemide administration: Loop diuretics can cause hyperuricemia and precipitate attacks of gout. This is caused by hypovolemia associated increase of uric acid reabsorption in the proximal tubule. It may be prevented by using lower doses to avoid development of hypovolemia.

 3. Allergic & other reactions: Except for ethacrynic acid, the loop diuretics are sulfonamides. Therefore, skin rash, eosinophilia and less often, interstitial nephritis are occasional side effects of these drugs.


Q. How do you manage hypokalaemia induced by frusemide?

Answer: Management of frusemide induced hypokalaemia:

 1. Stop the drug.

 2. K+  sparing diuretics should be given.

 3. Correct hypovolemia and reduce Na+  intake.

 4. K+  containing foods: Banana, guava, green coconut.

 5. Administration of  intravenous  KCI or K-containing syrup (after meal)

 6. Regular monitoring:

 • Vital signs: Pulse, blood pressure, respiratory rate, urine output, temperature etc.

 • 12 lead ECG for hypokalemic change in ECG report.

Q. What are the contraindications of loop diuretics?

Answer: Contraindications of loop diuretics:

 1. Hypersensitivity to loop diuretics (very rare).

 2. Overzealous use of any diuretic is dangerous in hepatic cirrhosis, border line renal failure, or heart failure

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