The Kidney and Drugs Flashcards
Define “clearance”
A measure of the rate at which a substance is removed from the blood
Define “steady-state”
Corresponds to the state of equilibrium obtained at the end of a certain number of administrations
Define “xenobiotics”
A chemical compound foreign to a given biological system
Give two examples of drugs which can be Ototoxic
Aminoglycosides
Loop diuretics
Define “diuretic”
Any substance which promotes water loss for control of disease in other tissues
What pH do the kidneys have?
5 - 7
The PCT reabsorption how much of all that is filtered by the Glomerulus?
2/3rds of filtrate
What is the component basis of Alkaline and Acidic diets?
Alkaline - vegetable based
Acidic - protein based
What pH does the stomach have?
3
Things below what Kd size can pass through the ultrafiltration barrier?
68
Some drugs may be small enough to pass through the ultrafiltration barrier, but still may not, why?
Some drugs i.e. warfarin may bind to plasma proteins such as albumin and therefore will not be cleared by the system
Give examples of things which are secreted out of PCT
Organic anions (negatively charged) and organic cations (positively charged)
Give examples of anionic drugs which are secreted out of the PCT
Penicillin, cephalosporins, salicylates, diuretics
Give examples of cationic drugs which are secreted out of the PCT
Trimethoprim, cimetidine, quinidine
Give an example of a lipid soluble drug which is completely reabsorbed by the kidneys
Diazepam
Give an example of a basic drug
Amphetamine
Give an example of an acidic drug
Aspirin
Define “half-life”
The time necessary to halve the plasma concentration of a drug
Why do drugs such as Aminoglycosides / Loop diuretics cause otoxocity?
They cause reduced clearance due to nephro-toxicity
Which part of the kidneys do Carbonic anhydrase inhibitors work on?
Proximal convoluted tubule
What is the normal role of Carbonic anhydrase in the kidneys?
Facilitate reabsorption of bicarbonate, sodium, and chloride into the kidneys from filtrate
What is the mechanism of action of Carbonic anhydrase inhibitors?
Inhibition leads to excretion of bicarbonate, sodium and chloride into the urine along with water, thereby causing diuresis and lowering blood pressure
Carbonic anydrase causes blood pH to become acidic - what is a compensatory mechanism exhibited by the patient?
Hyperventilation (Kussmaul breathing)
Give an example of 2 Carbonic anyhdrase inhibitors
Acetozolamide
Methazolamide
Where do Loop diuretics have their mechanism of action in the kidneys?
Ascending Loop of Henle
What transporter do Loop diuretics inhibit? What ions do they inhibit resorption of?
Na+/K+/2Cl- co-transporter, inhibiting Na and Cl reabsorption
Give 2 examples of Loop diuretics
Furosemide
Bumetanide
Where do Thiazides act on in the kidneys?
Distal Convoluted Tubule
What transporter do Thiazides inhibit? What ions do they inhibit resorption of?
Na+/Cl- symporter, inhibiting Na and Cl reabsorption
Which site of the kidneys do ADH work? What channels?
Collecting tubule / duct, Aquaporins (H2O channels)
Give one example of a thiazide drug
Bendroflumethizide
Where does the osmotic diuretic D-Mannitol work in the kidneys?
Ascending / Descending Loop of Henle
Where do K+ sparing diuretics work in the kidneys?
Collecting ducts
Give two examples of K+ sparing diuretic drugs
Amiloride
Spirinolactone
How do K+ sparing diuretics work?
Aldosterone receptor antagonist, increasing NaCl excretion and decreasing K excretion
