40 Questions
Loop diuretics inhibit Na+/K+/2Cl― co-transport system in the distal convoluted tubule of the nephron.
False
The absorption of bumetanide is erratic.
False
Diuretics are used to treat edema due to lymphatic obstruction.
False
Loop diuretics increase the excretion of Ca2+ in the urine.
True
Non-steroidal anti-inflammatory drugs (NSAIDs) enhance the effect of loop diuretics.
False
Loop diuretics are used to treat acute hypercalcemia without saline.
False
Loop diuretics cause vasoconstriction of the pulmonary vascular bed.
False
The effect of loop diuretics on renal PGE2 and PGI2 production leads to a decrease in RBF and GFR.
False
Furosemide is usually given in non-emergency situations
False
Hyponatremia increases the sensitivity of vascular smooth muscles to circulating catecholamines
False
Thiazide diuretics inhibit Na+/Cl― co-transport system in the proximal part of the PCT
False
Metabolic acidosis is caused by an increase in H+ ion excretion.
False
Primary hyperaldosteronism is an example of secondary hyperaldosteronism.
False
Furosemide causes peripheral vasodilation due to the production of prostaglandins in many vascular beds
True
Thiazide diuretics are absorbed from the liver
False
K+ sparing diuretics can cause hypokalemia.
False
Furosemide can cause reversible hearing loss
True
Loop diuretics can cause metabolic alkalosis.
True
Combining loop diuretics with K+ sparing diuretics can minimize the risk of electrolyte imbalance.
True
Ethacrynic acid is a derivative of sulfonamides
False
All cases of edema are caused by hyperaldosteronism.
False
Thiazide diuretics produce diuresis within 6-8 hours
False
K+ sparing diuretics are used to treat all cases of edema.
False
Combining loop diuretics with K+ sparing diuretics can minimize the risk of acid-base imbalance.
True
All diuretics are absorbed from the GIT.
True
Spironolactone is a direct inhibitor of Na+ channels in the distal part of the DCT.
False
Amiloride is metabolized by the liver.
False
Triamterene and amiloride have a fast onset of action.
False
The site of action of these diuretics is the proximal part of the DCT.
False
Spironolactone leads to a decrease in K+ retention.
False
These diuretics cause a significant loss of Na+ and water.
False
Triamterene and amiloride increase K+ excretion.
False
Thiazides can reduce urine volume in all cases of nephrogenic diabetes insipidus.
False
Thiazides are effective in reducing blood pressure in severe hypertension.
False
Thiazides decrease excretion of halides and H+.
False
Spironolactone is a non-steroidal potassium-sparing diuretic.
False
Triamterene and amiloride are steroidal potassium-sparing diuretics.
False
Thiazides are often used as a single agent in the treatment of hypertension.
False
Thiazides have a high efficacy in reducing sodium reabsorption.
False
Thiazides can cause hyperkalemia due to their mechanism of action.
False
Study Notes
Loop Diuretics
- Absorbed from the GIT and secreted into the lumen of the PCT by an organic acid excretory system
- Furosemide absorption is erratic, but bumetanide is complete
- Diuresis occurs within 5 minutes after i.v. administration and within 30 minutes of oral administration
- Mechanism of action: inhibit Na+/K+/2Cl- co-transport system in the thick ascending limb of LOH, leading to inhibition of active reabsorption of Na+, Cl-, and K+
- Effects: increased excretion of Ca2+, Mg2+, halides, and H+; increased renal PGE2 and PGI2 production, leading to vasodilatation and increased RBF and GFR
- Therapeutic uses: edematous conditions, acute pulmonary edema, acute renal failure, acute hypercalcemia, and acute hyperkalemia
- Adverse effects: hypovolemia, hypotension, electrolyte disturbances, hypokalemic metabolic alkalosis, hyperuricemia, and ototoxicity
Thiazide Diuretics
- Classification: true thiazides (derivatives of sulfonamides) and thiazide-like diuretics
- Pharmacokinetics: absorbed from the GIT, secreted into the lumen of the PCT by an organic acid excretory system, and produce diuresis within 1-2 hours
- Mechanism of action: inhibit Na+/Cl- co-transport system in the proximal part of DCT, leading to inhibition of active reabsorption of Na+ and Cl-
- Effects: increased excretion of halides and H+; decreased Ca2+ excretion and enhanced reabsorption
- Therapeutic uses: mild edematous states, essential hypertension, hypercalcuria, and renal Ca2+ stones, and nephrogenic diabetes insipidus
- Adverse effects: hypovolemia, hypotension, electrolyte disturbances, hypokalemic metabolic alkalosis, hyperuricemia, hyperglycemia, and hyperlipidemia
Potassium-Sparing Diuretics
- Classification: spironolactone, triamterene, and amiloride
- Pharmacokinetics: absorbed from the GIT, metabolized by the liver, and have slow onset (days)
- Mechanism of action: spironolactone is a competitive antagonist of aldosterone, while triamterene and amiloride are direct inhibitors of Na+ channels in the distal part of DCT
- Effects: mild Na+ and water loss, hyperkalemia, and metabolic acidosis
- Therapeutic uses: all cases of edema due to hyperaldosteronism, and in combination with loop diuretics or thiazides to minimize the risk of electrolyte and acid-base imbalance
This quiz covers the pharmacokinetics and pharmacological effects of loop diuretics, including furosemide, torsemide, bumetanide, and ethacrynic acid. Learn about their absorption, secretion, and mechanism of action.
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