Drug Disposition Flashcards
What is the blood flow to the liver?
680ml/min/kg
What is protein binding?
Binding of drug onto plasma proteins, only unbounded drugs can diffuse through the cell membranes
What is drug metabolism?
Enzyme conversion of lipid soluble compound into water soluble compound
Where does drug metabolism mostly occur?
Liver
Where else can drug metabolism occur?
Kidney, GI Tract, Brain, Plasma and Lungs
What is Phase 1 reactions?
- Modify the chemical structure of a drug
- Makes drug more water soluble
- Prepares for phase 2
- Product can be more chemically reactive than the parent drug
PHARMACOLOGICAL ACTIVATION
What is Phase 2 reactions?
- Conjugate drug to large molecules, amino acids, sulphate groups, glucuronic acid.
- Water soluble and easily excreted
- Increased molecular weight
- Inactive
PHARMACOLOGICAL INACIVATION
What is pharmacological inactivation?
The modification of drug structure which makes decrease receptor affinity and enhance excretion
What can happen to drug metabolising enzymes?
They can be induced or inhibited
What is in a medicine?
Active Drug + Excipients
What is drug excretion?
Removal of drug from the body
What is drug half-life?
The time taken for amount of drug in body to decrease to half
What is the importance of drug half-life?
- Prevents drug interaction via allowing you to know when one drug has be eliminated from he body.
- Important to determine how long a toxic concentration of drug will take to decrease
What is the drug therapeutic window?
The range of drug dosage from minimum therapeutic concentration to minimum toxic concentration
Consequences of renal and hepatic diseases on drugs?
Drug concentration may reach toxic levels due to elongated half life
