diuretic drugs Flashcards
What are Diuretic drugs
Drugs that increase the rate of urine formation resulting in the excretion of sodium and water
Purpose of diuretic drugs
Used to treat hypertension and heart failure. Also used to prevent kidney damage during acute kidney injury
How much sodium/water is reabsorbed to the bloodstream by the proximal convoluted tubule
60-70%
How much sodium/water is reabsorbed in the ascending loop of henle
20-25%
How much sodium is reabsorbed in the distal convoluted tubule
5-10%
5 categories of diuretic drugs
- Carbonic anhydrase inhibitor(used for glaucoma)
- Loop diuretics
- Osmotic Diuretics
- Potassium sparing diuretics
- Thiazide and thiazide like diuretics
Most common carbonic anhydrase inhibitor
Acetazolamide
Should Acetazolamide be used in pregnant women
Yes it should be used as the benefits out weight the potential fetal risks
What does the carbonic anhydrase ENZYME do?
The enzyme makes H+ more available which then increases the transport of water and sodium back into the blood
What does the carbonic anhydrase INHIBITOR do?
decreases the concentration of the enzyme which then blocks the production of H+ decreasing the transportation of water and sodium leading to more bicarbonate, sodium water and potassium to be excreted
Indications of carbonic anhydrase inhibitors
- open angle glaucoma and secondary glaucoma
- Lower intraocular pressure before eye surgery
- Edema (secondary to HF)
- High altitude sickness
- Epilepsy
Carbonic Anhydrase inhibitor contraindictions
- drug allergy
- Hyponatremia (low levels of sodium)
- Hypokalemia (low levels of potassium)
- Severe kidney/liver dysfunction
- Adrenal gland insufficiency
- Cirrhosis (liver scarring/damage)
Carbonic Anhydrase inhibitor adverse effects
- Acidosis (decreases bicarbonate absorption which makes blood less acidic)
- Hypokalemia
- Drowsiness
- Anorexia
- Paresthesias
- Hematuria
- Urticaria
- Photosensitivity
- Melena (blood in the stool)
Carbonic Anhydrase inhibitor interactions
- can cause hypokalemia so when used with digoxin, may cause toxicity
- Used with corticosteroids can cause hypokalemia
- Increases effects of amphetamines, carbamazepine, cyclosporine, phenytoin, and quinidine sulphate
Loop diuretic drug Ex
Furosemide (Lasix)
Loop diuretics MOA
- Effects kidney, cardiovascular and metabolism
- Act directly on the ascending loop of henle to block chloride and sodium reabsorption
- Increases kidney prostaglandins leading to dilation of blood vessels reducing kidney, pulmonary and systemic vascular resistance
Loop diuretics onset/duration
rapid onset that last 2 hrs
Loop Diuretics drug effects
- Increases fluid loss leading to a reduction in BP, pulmonary/systemic vascular resistance, central vascular resistance, left ventricular end diastolic pressure
- potassium/sodium depletion and small calcium loss
Loop Diuretics indication
- Edema associated with HF and liver/kidney disease
- Control hypertension
- hypercalcemia
- HF from diastolic dysfunction
Loop Diuretics Adverse effects
CNS: Dizziness, headache tinnitus, blurred vision
GI: Nausea, vomiting, diarrhea
Hematological: agranulocytosis, neutropenia, thrombocytopenia
Metabolic : hypokalemia, hyperglycemia, hyperuricemia
Loop Diuretics interaction
- neuro/nephrotoxic
- Cause an increase of uric acid, glucose, alanine aminotransferase and aspartate aminotransferase
- With thiazide can cause nephron blockage
- NSAIDs may decrease the reduction of vascular resistance
Uses for Furosemide (lasix)
- Most commonly used loop diuretic
- Uses: pulmonary Edema, edema associated with HF, liver disease, nephrotic syndrome, ascites and and hypertension
Most commonly used osmotic diuretics
Mannitol
Where are Osmotic Diuretics effective
Works all along the nephron but mostly in the proximal tubule and the descending loop of henle
