Diuretics Nursing Care and Drug Study

Diuretics

Diuretic is an agent that increases urine volume, while a ‘natriuretic’ causes increase in renal sodium excretion. It is a golden rule, water leads to follow sodium, where sodium goes water follows it, therefore natriuretic are usually called diuretics.

Diuretics decreases blood pressure broadly by two actions :

• by decreasing plasma volume
• by depleting sodium in the body.

Initially diuretics reduce blood pressure by reducing blood volume and cardiac output. Secondly, diuretics controls sodium level in the body which controls long-term blood pressure. Because sodium is believed to contribute in vascular resistance by increasing vessel stiffness, thus cause increase in blood pressure which can be reversed by the use of diuretics.

TYPES OF DIURETICS:

There are usually five types of diuretics that are commonly used to treat high blood pressure. They are divided according to their action on different parts of nephron. These diuretics are:

1. Osmotic Diuretic
2. Loop Diuretic
3. Thiazide Diuretic
4. Potassium sparing Diuretic
5. Carbonic Anhydrase Inhibitors (CAI)

Aldosterone antagonists and Antidiuretic Hormone (ADH) agonist sometime also considered as Diuretics because of their diuresis action and help in decreasing plasma volume

GENERAL USE OF DIURETICS IN HYPERTENSION:

Thiazide diuretics

Thiazides diuretics are appropriate for most patients with mild to moderate hypertension and normal renal and cardiac function. It may be used as initial drug therapy for hypertension treatment

Loop diuretics

Loop diuretics are most powerful diuretics and use in severe hypertension. Often, Furosemide use in hypertension emergencies to prevent the volume expansion during the administration of powerful vasodilators.

Potassium-sparing diuretics

Potassium-sparing diuretics are useful both to avoid excessive potassium depletion and to enhance the natriuretic effects of other diuretics.

DIURETICS AND THEIR SITE OF ACTION AT THE MAJOR SEGMENT OF NEPHRON:

Diuretics Segment of Nephron Functions of diuretics

Osmotic diuretic

Osmotic diuretic Proximal convoluted Tubule (PCT), Collecting ducts Inhibits water reabsorption in the tubule by increasing solute concentration within the tubules.

Carbonic Anhydrase Inhibitor (CAI)

Carbonic Anhydrase Inhibitor (CAI) Proximal convoluted tubule (PCT) Block reabsorption of NAHCO3 by blocking Carbonic Anhydrase Enzyme.

Loop diuretics

Loop diuretics Loop of Henle (Thick ascending limb) Selectively inhibits NaCl reabsorption
Thiazide diuretic Distal convoluted tubule Inhibits NaCl reabsorption

Potassium-sparing diuretics

Potassium-sparing diuretic Late Distal convoluted tubule (LDCT) and Collecting tubule. Reduce Na absorption the LDCT and collecting tubule.

INDICATIONS OF DIURETICS:

Abnormalities in fluid volume and electrolyte composition in the body are very common and case many clinical disorders. Drugs (Diuretics) that block specific transport function of renal tubules are valuable clinical tools in the treatment of these disorders. Diuretics may be indicated in any of these conditions.

1. Edematous state

   • Edema as a result of Cardiac, Renal or Vascular disease.
   • Heart Failure
   • Kidney diseases (that interfere with volume homeostasis)
   • Hepatic Cirrhosis
   • Idiopathic Edema

2. Non Edematous state

   • Hypertension
   • Nephrolithiasis
   • Hypercalcemia
   • Diabetes Insipidus

SIDE EFFECTS/ADVERSE EFFECTS Of DIURETICS:

Diuretics cause to increase urination and loss of minerals, as a result of which dehydration and loss of sodium from the body is common. Hypotension is also cause because of low plasma volume. Other side effects include:

• Nausea
• Dizziness
• Constipation
• Thirst and dry mouth
• Muscle cramp (loss of calcium
• Hypokalemia (only related to loop diuretics, Thiazide diuretics and CAI which further cause Arrhythmia, Muscle weakness)
• Hyperkalemia (related to Potassium-sparing diuretics)
• Hyperuricemia (Increase levels or uric acid cause Gout arthritis)
• Metabolic Acidosis (CAI, K-sparing diuretics)
• Metabolic Alkalosis (Thiazide diuretics, Loop diuretics)
• Hypercalcemia (related to Thiazide diuretics only)

DRUG INTERACTIONS:

• Enhanced hypotensive effects when given with diuretics:
  • ACE Inhibitors,
  • Adrenergic Receptor Blockers,
  • Alcohol,
  • Aldesleukin,
  • Alpha-Blockers,
  • Alprostadil,
  • General Anesthetics,
  • Angiotensin II Receptor Antagonist,
  • Anxiolytics,
  • Hypnotics,
  • Baclofen,
  • Beta Blockers,
  • Calcium Channel Blockers,
  • Clonidine,
  • MAOIS,
  • Methyl Dopa,
  • Minoxidil,
  • Moxonidine,
  • Nitrates,
  • Sodium Nitroprusside,
  • Tizanidine.
• Cause Hypokalemia when given with diuretics: Amisulpride, Atomoxetine, Pimozide, digoxin cause hypokalemia when given with diuretics.
• ACE Inhibitors and NSAIDS cause hyperkalemia when given with diuretics.
• Tricyclic Antidepressant causes increase risk of hypotension when given with diuretics.
• Carbamazepine increase risk of hyponatremia when given with diuretics.
• Corticosteroids, Indomethacin, Estrogens, Phenothiazine, and Ketorolac antagonize the diuretic effects when given with diuretics.
• Diaz Oxide enhanced hypotensive and hyperglycemic effects when given with diuretics.
• Diuretic reduce the effects of oral antidiabetic drugs and Insulin hence, dose may need to increase.

NURSING INTERVENTIONS :

• Obtain complete health history (Electrolyte balance & renal function)
• Obtain vital signs with the baseline values specially Blood pressure
• Find out patient’s medication history including alcohol and nicotine consumption to avoid drug interaction
• Determine possible drug allergies of patient.
• Obtain blood and urine specimen for laboratory analysis
• Observe for any change in consciousness, dizziness, fatigue, postural hypotension
• Monitor for fluid intake by measuring intake, output and daily weight.
• Monitor laboratory values specially potassium and sodium levels, BUN, Serum Uric acid.
• Monitor hearing and vision (because some loop diuretics are ototoxic & thiazide diuretic produce visual change by increasing digoxin level)

PATIENT EDUCATION:

• Explain the right use of diuretics with dosage
• Advise them to take with meal
• Report any visible s/s of proximal edema, SOB, potential sign of Heart Failure or Pulmonary edema
• Report immediate if feeling dizzy or change in consciousness
• Advise them to change position slowly to avoid postural hypotension
• Monitor BP as specified by the HP
• Mention possible side effects that can cause by the use of diuretics such as dry mouth, increase in urination.
• Take potassium containing diet if using loop or thiazide diuretics
• Avoid potassium containing diet if using potassium-sparing diuretics.
• Ask health care professional before taking any vitamin/minerals or other supplements
• When outdoor, wear dark glasses or light color clothe because some diuretics cause photosensitivity.