Metabolism and Excretion Flashcards Preview

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Flashcards in Metabolism and Excretion Deck (19)
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1
Q

List 7 inducers

A
Rifampin
St. John's Wort
Phenobarbitol 
Phenytoin
Carbamazepine
Tobacco Smoke 
Ethanol
2
Q

List 7 inhibitors

A
Cimetidine
Erythromycin/ Clarithromycin 
Ketoconazole/ Azole antifungals 
Fluoxetine
Grapefruit
HIV protease inhibitors
Omeprazole
3
Q

What type of metabolism is affected by old age?

A

Mostly cytochrome metabolism so you have to adjust dosage

4
Q

What is P-glycoprotein?

A

Transporter which plays a role in the elimitation of xenobiotics

5
Q

What do P-glycoproteins do to xenobiotics at the GI tract?

A

They reduce absorption by expelling them from the cells

6
Q

What do P-glycoproteins do to xenobiotics at the liver and kidey?

A

They enhance elimination

7
Q

P-glycoproteins share the same inducers and inhibitors at what mechanism?

A

Cytochrome P450

8
Q

What would happen to the plasma concentration of xenobiotics if you induce P-glycoproteins?

A

Cp would decrease

9
Q

What would happen to the plasma concentration of xenobiotics if you inhibit P-glycoproteins?

A

Cp would increase

10
Q

What kind of drugs do kidneys excrete?

A

water soluble

non volatile

11
Q

Describe glomerular filtration

A

drug less than 69000 MW
Rate- 120ml/min
No protein bound drug

12
Q

Describe Active tubular secretion

A

Directly from blood to urine
120-600ml/ml
strong acids and bases in proximal tubule
Protein binding does not effect secretion half-life

13
Q

Rate of tubular reabosorption

A

1ml/min

14
Q

where does passive diffusion of the kidney occur?

A

Proximal and distal tubule. Weak acids or bases depends on pH of urine

15
Q

Active reabsorption is important for what molecules?

A

Endogenous

16
Q

What are the characteristics of drugs excreted via biliary and fecal excretion?

A

Highly water-soluble and High molecular weight

17
Q

Describe enterohepatic circulation

A

Drug metabolised in liver
Enters bile duct
Enters GI and gets hydrolyzed back to parent drug by bacterial enzymes
Reabsorbed

18
Q

What do antibiotics do to drugs that are enterohepatically recycled

A

Decrease plasma concentration by decrease enzyme producing bacteria

19
Q

Do most drugs pass into the breast milk

A

Yes, but at low levels so you can ensure lowest levels by desyncronizing breastfeeding and Cmax of drug