Pharmacology Flashcards
Things that affect biovailability
Food: decreases absorption and bioavailability
First pass effect
Volume of distribtuion
Lipid Soluble: High Vd
Water Soluble: Low Vd
Two phases of hepatic metabolism
1) Oxidation, reduction, hydrolysis
- Via CYP enzymes
2) Conjugation
Common CYP3A4 inhibitors
1) Erythromycin
2) Azoles
3) Verapamil
4) Diltiazem
Common CYP2D6 inhibitors
1) Quinidine
2) Neuroleptics
3) Fluoxetine
Common substrate of CYP3A4
1) Warfarfin
2) Dabigatran
3) Carbemazepine
4) Methyprednisolone
Ineffective CYP2D6
Poor metabolism of codeine
Timolol –> systemic beta blockade
Perhexiline –> Neuropathy and liver toxicity
Drugs that decrease INR i.e induce CYP3A4
Carmbeazepin and Phenytoin
Rifampicin
Cholestyramine
St Johns Wort
Function of p-glycoprotein
Contains an efflux mechanism which reduces uptake from the gastrointestinal system
> inhibitors will therefore increase absorption of drug
> inducers will therefore decrease absorption of drug
What does an FU of 1 mean?
Completely really excreted
Steady state formula
SS = bioavailability*dose/dosing interval
What does giving a loading dose establish?
Immediate establishment of steady state
What is first order kinetics
A similar proportion of drug is excreted per each unit of time.
What is Xero order kinetics
The same amount of drug is excreted per each unit of time.
HLA associated with side effects of Carbemazepine/Lamotrigine/Phenytoin
HLA-B*1502
HAN Chinese
