Diuretics Classification With Furosemide Pharmacology

Diuretics

Diuretics are Substances or drugs that are used to enhance or to modulate or to potentiate diuresis.OR Any agents or drugs that increase the volume of urine and any agents that increase the excretion of sodium (Na+) in the urine is called natriuretic or diuretics.

Classification:

(1)Thiazides diuretics

  • chlorothiazide
  • chlorthalidone
  • indapamide
  • hydrochlorothiazide
  • methyclothiazide
  • metolazone

(2)Loop diuretics

  • bumetanide
  • furosemide
  • ethacrynate
  • torsemide

(3)Potassium-sparing diuretics

  • Amiloride hydrochloride
  • spironolactone
  • triamterene

(4)Carbonic Anhydrase inhibitors:

  • Acetazolamide
  • Methazolamide.

Furosemide:

Also known as frusemide.
Therapeutic Category:

  • It is one of the loop diuretics
  • One of the antihypertensive
  • Drug of choice in pulmonary edema
  • Drug of choice in generalized edema
  • (Oedema related to myocardial infarction and Oedema related to liver cirrhosis.

DOSAGE FORM & STRENGTHS:

It is available in solution,tablets as well as injectable form

  • Solution: 8,10 mg/ml
  • Tablet:20 mg,40mg,80mg
  • Injections:10 mg/ml,2ml.
  • Commercial Product and Trade names:
  • Frusemix 40mg (Abbot)
  • Losix 20,40 mg (Aventus)

Pharmacokinetics:

After oral administration absorption is satisfying, more the  40-60% of the drug have absorption capability.

The onset of action:

In the case of solid dosage form, its onset of action is 30-60 minutes.

  • Peak effect is 1-2 hours
  • Time half: (T1/2)
  • Almost 1 hour
  • Protein Binding-More then  80% of the drug have the protien binding ability.

Mechanism of action:

As for the mechanism of action is a concern it is restricted to the loop of Henle and distilled part. it blocks Na-K+2cl- Cotransporter. Overall the drug is responsible to reinhabit the absorption of Na+, Cl-, Mg+ while on the other side responsible for excretion of H+and K+ ions by tubular secretions overall effect is reabsorption of various ions net result will decrease plasma volume, in other words, we can say it decreases peripheral resistance,venous return to heart, decrease diastolic blood pressure,so obviously there will decrease heart rate, cardiac output, and decrease systolic blood pressure.so loop diuretic has the ability to decrease diastolic blood pressure by direct pathway while systolic blood pressure by indirect pathway.

Indications:

1)Acute pulmonary Oedema:

It  is most commonly related to lung directly related to deoxygenated blood ,specially in condition like if a person is suffering from congestion of lungs so on one side it increases the quantity of deoxygenated blood towards lungs while on another side due to congestion leads to increase permeability at the level of endothelial cell so liquid portion will ooze out towards interstitial area which is responsible for pulmonary edema.
By taking the support of loop diuretic peripheral resistance and venous return will decrease. this lead to decrease workload on the heart obviously the contractility of the heart will be decreased which in turn will decrease transportation toward lungs.

2)Generalized Oedema.

Loop diuretic specially frusemide use in the generalized type of edema relating to some pathological conditions like CHF, tachycardia, and liver cirrhosis.

3)Hyperkalemia.

Loop diuretic is used in hyperkalemia because it blocks Na-K+2cl- Cotransporter and block K+(Potassium) to go to the blood so potassium level in blood decreases.
4)Hypertension:
Loop diuretic is used in hypertension in aged candidates while taking the support of strips management protocol for hypertension.also used to decrease Na+ intake,  Decrease alcohol consumption especially in pregnancy. Also used in hypermagnesemia and hypernatremia.

Adverse effects:(ADR)

  • Hypokalemia
  • Hyperuricemia
  • Hypocalcemia
  • Hypomagnesemia
  • Hyponatremia
  • Systemic alkalosis
  • Orthostatic hypotension
  • Osteoporosis if used for a long time.

Precautionary measurement:

1)Monitor for possible occurrence of blood dyscrasia and liver damage, monitor urine and blood pressure in diabetes.
2)Frequently monitor serum electrolyte
3)In case of lactating mother it crosses and excreted in milk so can affect the child.
4)In case of children may increase the incidence of patent ductus arteriosis in premature infant especially with respiratory distress.
5)Persons Showing hypersensitivity reactions towards sulphonamide can show allergic reaction to frusemide.
6)Renal function: If increasing azotemia and oliguria occur during treatment abruptly discontinue the drug.

Drug interactions:

1)Interaction of other antihypertensive drugs with frusemide increase the effects of frusemide. If used with other antihypertensive agents then reduces the dose by at least 50%.
2)Frusemide Increase plasma lithium level and cause toxicity.
3)NSAIDs Decrease the effects of frusemide
4)Phenytoin may reduce the diuretic effect of frusemide.
4)Interaction of frusemide with thiazide diuretic can show the synergistic effect that may result in profound diuresis and serious electrolyte abnormalities.

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