Intro To PPT Flashcards
What is apparent volume of distribution
The theoretical volume that would contain the drug in comparison to blood plasma levels of the drug
Can be calculated by dividing the amount of drug in the body / plasma concentration of the drug
Apparent volume of distribution is affected by which factors
Size
Plasma binding to proteins
Charge polarity
Lipophilicity
The larger the volume of distribution the more likely the drug is not likely to be not found in the plasma.
A low Vd suggests that it is a large or polar drug which remains within the plasma or water
A high vD suggests that the drug is more likely to be sequestered in other things like fat and muscle
What is the definition of half life
Time taken for concentration of drug within plasma to half
Half life can be altered by which two factors
- clearance
- vD
What is steady state
Input of the drug is equal to the excretion of the drug
What is the definition of clearance
The volume of blood cleared of drug /unit time eg L /hr or mL/ minute
What is elimination
Amount of drug cleared from the blood per unit time
Mg/min
Fe value for a drug tells you what
Whether a drug is renally excreted or excreted via liver metabolism
Fe = 1 - renal excretion
What is the difference between first and zero order kinetics
In zero order kinetics there is a constant amount of drug eliminated per unit time regardless of the concentration of the drug ( a set amount is removed every time) - due to the saturation of enzymes
In first order kinetics the amount of drug eliminated depends on its concentration ( A set % is removed every time)
What does metabolism aim to do tot he drug
- phase 1 reactions are catabolic - break down the drug via oxidation, reduction and hydrolysis
- in phase 2 the reactions are mostly anabolic and aim to conjugate things to the drug to make metabolites less reactive and easier to excrete
Drug adherence
The extent to which a patients actions matches the agreed recommendations
Drug compliance
Extent to which a patient takes their meds
Drug concordance
HC professional and patient create agreed plan for treatment by forming a therapeutic alliance
Some reasons for poor adherence to meds
- lack of knowledge on disease and meds
Alternative sources of medication
If clashes with lifestyle or don’t want to deal with SE
Lack of trust towards HC staff or big pharma
