5 - Diuretics and Kidney Failure Drugs Flashcards
What are the four broad functions of the kidney?
- Regulatory: fluid, acid, electrolyte
- Excretory: waste and drugs
- Endocrine: renin, EPO, prostaglandins
- Metabolism: Vit D, insulin, morphine, paracetamol
What are the seven different types of diuretic drugs acting on the kidney?
- Carbonic anhydrase inhibitors
- Osmotic diuretics
- Loop diuretics
- Thiazides
- K+ sparing diuretics
- Aldosterone antagonists
- ADH Antagonists
- (SGLT2 inhibitors)
What are the definitions of the following:
- Diuretic
- Natriuretic
- Aquaretic
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/495/a_image_thumb.jpeg?1579775468)
How do carbonic anhydrase inhibitors work and what are their side effects?
- Sodium bicarbonate diuresis
- Stops bicarb being broken down by blocked CA enzyme so cannot be absorbed
- Hypokalemic metabolic acidosis as loss of bicarb and upregulation of ENaC and therefore ROMK in the distal tubules
- Not used as diuretics anymore as fast tolerance, more like glaucoma
Hypokalaemia
Metabolic Acidosis
Acidemia
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/500/a_image_thumb.jpeg?1579775646)
How do osmotic agents work as diuretic, what are some side effects and an example of this kind of drug?
- Mannitol: used in ITU setting to relieve raised ICP
- Filtered at glomerulus
- Increase osmotic gradient throughout nephron
- Excessive water loss
- Hypernatraemia as so much H2O loss and little Na loss
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/502/a_image_thumb.jpeg?1579775892)
How can SGLT2 inhibitors work as diuretics?
Originally an antidiabetic but the loss of Na by blocking SGLT2 means it also acts as a diuretic
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/503/a_image_thumb.jpeg?1579776168)
What are the actions of loop diuretics, some side effects and some examples?
- Bumetanide and Furosemide
- Inhibit NCCK transporter in thick ascending limb so less Na and Cl aborsbed
- Leads to loss of Ca and Mg as they need ROMK to be absorbed
- Hypokalemic metabolic alkalosis as upregulation of ENac further down
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/505/a_image_thumb.jpeg?1579776478)
What are the actions of thiazides and what are some side effects?
- Inhibits NaCl reabsorption in DCT at NaCl channel
- Promotes Ca reabsorption due to increase use of NCX
- Hypokalaemia due to upregulation of ENaC in CD
- Hyperuricaemia
- Hypercalcaemia (MAIN IDEA SINCE MORE ACTIVE NCX SINCE CALCIUM CHANNEL IS STILL ACTIVE)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/508/a_image_thumb.jpeg?1579776651)
How does spironolactone act as a diuretic and what are some side effects of the use of this?
- Aldosterone receptor antagonist so inhibits Na+ retention (Na-K ATPase / Na+ flux) in collecting duct
- Blunts K+ and H+ secretion so can give with other diuretics that cause hypokalaemia
- Androgenic cross-reactivity (gynacomastia)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/511/a_image_thumb.jpeg?1579776834)
Where does aldosterone act in the kidney?
- Aldosterone increases expression of ENaC and Na/K/ATPase in principal cells of the collecting duct
- Spironolactone is the aldosterone receptor antagonist
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/514/a_image_thumb.png?1579776918)
How do ADH antagonists work?
And examples?
- ADH antagonists (aquaretics) reduce concentrating ability of urine in collecting ducts by blocking V2 receptor
- Tolvaptan: treats hyponatraemia and prevents cyst enlargment in APCKD as no AQP inserted
- Lithium: used to treat bipolar but also inhibits ADH action so get poyuric and dehydrated
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/518/a_image_thumb.jpeg?1579777176)
Where do ADH antagonists act?
Aquaretics act on principal cells of the collecting duct
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/521/a_image_thumb.jpeg?1579777258)
Where do each of the main diuretics act in the nephron?
- CA inhibitors: PCT
- Osmotic diuretics: all over but mainly PCT
- Loop diuretics: thick ascending
- Thiazides: late DCT
- K+ sparing diuretics: DCT and CD
- Aldosterone antagonists: CD
- ADH Antagonists: CD
- (SGLT2 inhibitors): PCT
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/522/a_image_thumb.png?1579777344)
How do alcohol and caffeine have a diuretic action?
Caffiene act on adenosine receptors which cause vasodilation and therefore increased blood flow to the kidney
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/524/a_image_thumb.jpeg?1579777586)
In general what are the side effects that can occur with diuretics?
- Hypovolaemia and hypotension leading to AKI
- Electrolyte disturbances
- Metabolic disturbances
- Anaphylaxis (mainly loops)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/432/336/526/a_image_thumb.png?1579777738)