31 - Renal Drugs Pt 2 Flashcards
What is a diuretic?
increases solute excretion to increase the volume of urine
What is an aquaretic?
Increase water but not solute excretion
What is a natriuretic?
Increases excretion of sodium
What is a saluretic?
Increases the excretion of sodium and chloride
What is a kaliuretic?
Increases the excretion of potassium
What are 2 medical conditions that diuretics are used to treat?
- Hypertension
- Edema
What are the primary and secondary sites of action of carbonic anhydrase inhibitors?
- Primary - PCT lumen
- Secondary - distal collecting duct
What is the major effect of carbonic anhydrase inhibitors in the nephron?
Causes excretion of sodium bicarbonate, i.e. Sodium bicarb remains in the urine
What are carbonic anhydrase inhibitors expected to cause - metabolic acidosis / alkalosis?
They cause acidosis, so can be used to treat metabolic alkalosis
Carbonic anhydrase inhibitors affect the secretion of the following ions: Na, K+, H+, HCO3 and H2PO4. Secretion of which ones are increased or decreased by these drugs?
- Increased - Na, K+, HCO3 and H2PO4 increased.
- Decreased - H+
What is the example of the carbonic anhydrase inhibitor we need to remember? Why is it regarded as a potassium wasting drug?
- Acetazolamide
- A lot of Na+ reaches the distal nephron, K+ exchanged to absorb that Na+. Exchanged K+ is excreted
Open angle glaucoma, presurgical relief of glaucoma pressure, altitude sickness and counteracting diuretic induced metabolic alkalosis. These are all treated with what type of diuretic?
Carbonic anhydrase inhibitor (Acetazolamide)
Allergic reactions, metabolic acidosis, increased circulating ammonia, kidney stones, bone marrow depression, parasthesia and tingling can all be caused by _
Carbonic anhydrase inhibitor (Acetazolamide)
What patients should not use acetazolamide?
Patient’s with liver cirrhosis - Renal ammonia returns to system, can worsen hepatic encephalopathy
What is the mechanism of osmotic diuretics? What is the effect on the medullary salt gradient? What is the primary site of action in the nephron?
- Draws water from tissues into blood, increase renal blood flow and thus urine
- It washes out the gradient
- Loop of Henle
What is the effect of osmotic diuretics on ADH activity?
Prevents the action of ADH (water reabsorption) because salt gradient is disrupted i.e. can’t resorb water even if dehydrated
Osmotic diuretics affect the excretion of Na+, K+, Ca++, Mg++, CL-, HCO3- and H2P04. What is increased and what is decreased from this list?
It increases the excretion of EVERYTHING.
What are the 2 examples of osmotic diuretics we need to know? Which can cause hyperglycemia?
- Glycerin (may cause hyperglycemia after metabolism)
- Mannitol
Acute renal failure, tubular necrosis, dialysis disequilibrium, acute glaucoma for high intraoccular pressure. These are all uses of _
Osmotic diuretics
Hyponatremia and dehydration are potential side effects of _
Osmotic diuretics
What are 3 populations that should be cautious about using osmotic diuretics?
- Pulmonary congestion as it can become pulmonary edema
- Patients with Anuria
- Patients with intracranial bleeding (Mannitol)
What is the primary site of action of the loop diuretics i.e. where in the loop? How do they enter the lumen?
- Thick ascending limb of loop of Henle
- Organic ion transporters in proximal tubules
What is the specific transporter inhibited by the loop diuretics? What is its effect on the medullary ion gradient? What is its effect on urine volume and concentration?
- Na, K, Cl Symporter
- Diminishes the ion gradient
- Increases urine volume, Increased concentration
Loop diuretics affect excretion of Na+, K+, H+, Ca++, Mg++, Cl-, HCO3- and H2PO4-. Excretion of which are increased and which is decreased?
ALL ion excretion is increased. None are spared
