14. Renal Flashcards
Thiazides
act where
Cause what
Which is more potent v furosemide
Other affects
metabolic x4
Prox DCT
luminal NaCl Symport = secretion
Increased Na to distale drags potassium
activates RAAS
< potent than loop
Metab Reduce insulin secretion Rise chol ; TG Gout exacerb - red urate secr HyperCa
HypoCl HypoK Alkalosis
Red SVR - main exertion of hypotensive effects
0
0
Loop diuretic
inhibit what
NA K cl symporter
Amiloride inhibits what
Epithelial sodium channels
Inhibitors of vasopressin examples x2
cause what condition
Drugs which lead to nephrogenic diabetes insipidus such as lithium and demeclocycline.
Hartmanns contains & mmol
Osmolality
Sodium 131 mmol/l Chloride 111 mmol/l Potassium 5 mmol/l Calcium 2 mmol/l Lactate 29 mmol/l.
278 mosmol/kg,
Captopril
Mech- result
RBF?
SVR
Dry cough?
ACE inhibitors
Conversion Ag1->Ag2
Red aldosterone secretion,
Natriuresis.
RB flow is increased
Renal artery stenosis renal perfusion red
SVR red
The dry cough seen with ACE inhibitors is thought to be due to an accumulation of bradykinins.
Hypoklaemia
From
- insulin therapy
Cell membrane sodium-potassium = intracellular shift of potassium. - Nebulised salbutamol is a recognised treatment for hyperkalaemia.
- Prednisolone is capable of producing hypokalaemia due to excessive potassium excretion.
- conversely aldo antag - hyperk - Thiazide
5 Loops
Hyper
- Addison’s is associated with hyperkalaemia.
- Spironolactone is associated with potassium retention.
- ACEi
Mannitol
Osmotic diuretic Filtered at the glomerulus - not reabsorbed - creates an osmotic gradient - excreted - osmotic equivalent of water
Forced diuresis to treat drug overdoses
cerebral oedem
maintain a diuresis during surgery.
- Renal prostaglandins
= Renal arteriolar dilation
= tubular urine flow that is thought
protect against renal injury by reducing tubular obstruction by cellular debris. - free-radical scavenger
Reduces the harmful effects of free radicals during ischaemia-reperfusion injury.
- oxygen free radical scavenging properties,
-reduce the risk of an ischaemia-reperfusion injury.
Thiazides act where
Act where
On what
Thiazides, of which metolazone and bendroflumethiazide are examples, inhibit sodium reabsorption at the distal convoluted tubule.
Loop diuretics
Act where
Loop diuretics inhibit reabsorption from the ascending limb of the loop of Henle.
Spirinolactone
What is it
Acts where
Spironolactone is a synthetic steriod with an aldosterone-like structure which antagonises the effect of aldosterone on the distal convoluted tubule and collecting duct. It also has anti-androgen effects.
Mannitol is
acts where
Mannitol is an osmotic diuretic and works primarily on the proximal convoluted tubule but also has secondary effects on the descending loop of Henle and collecting ducts.
Bumetanide
Bumetanide is a loop diuretic
- plasma protein bound (>98%),
- cannot be freely filtered into the glomerulus, it is secreted into the tubular lumen by an organic acid transporter
- excreted unchanged.
It inhibits the Na+K+2Cl- co-transporter in the ascending loop of Henle, leading to an increased delivery of sodium and water to the distal convoluted tubule.
It is forty times more potent than furosemide.
Oxygen consumption in the nephron is decreased by loop diuretics and in the loop of Henle this may be reduced to basal levels.
Loop diuretics are associated with:
Hypokalaemia Hyponatraemia Hypomagnesaemia, and Metabolic alkalosis. They can also reduce ventricular preload by causing vasodilatation.
Thiazides
act @
causes
which also causes and may lead to
Also act at -
causing
s/e
mainly at the proximal part of the distal convoluted tubule to inhibit active resorption of sodium and chloride.
There is increased excretion of potassium and hydrogen ions (rather than inhibition of resorption) and a hypokalaemic alkalosis may develop.
They also act at the proximal tubule and cause weak inhibition of carbonic anhydrase, and have a direct vasodilatator action.
Side effects of thiazides are numerous and include:
Hypokalaemia
Hyponatraemia
Hyperuricaemia
Hypomagnesaemia
Hypercholesterolaemia (and high triglycerides) and rarely
Thrombocytopenia.
Hyperglycaemia occurs due to an enhancement of glycogenolysis and reduced insulin release.
