Metabolism and excretion Flashcards
What is metabolism?
The process by which a drug is converted into a form that aids its elimination from the body.
What is the major site of metabolism?
The liver
What is the process of phase 1?
Involves chemical reactions such as oxidation,reduction and hydrolysis. This is where the drug/toxin becomes more polar and inactive.
What is the process of phase 2?
Phase 2 -addition of a structure to the drug/toxin. Phase 2 involves the chemical reactions that chemically change the drug or phase 1 metabolites into compounds that are soluble enough to be excreted through urine. E.g sulfation,acetlaytion and Methylation
what are cytochrome P450 enzymes?
These are enzymes that are present in the liver and assist in the metabolism of drugs and toxins
What is oxygenation?
It is the addition of oxygen-there is stable and unstable oxygen.
What is deamination?
The removal of amines
What is N-hydroxlaytion?
The addtion oxygen that is attached to a hydrogen and hydrogen is attached to a nitrogen?
what is enterohepatic circulation?
This is the circulation of billirary acids,bilirium,drugs from the liver to the bile, then to the small intestine then absorption takes place by the enterocytes and then transported back into the liver.
What is first order kinetics?
The rate of elimination is proportional to the amount of drug in the body. The higher the amount of drug, the longer it will take for the drug to be eliminated from the body per a unit time.
What is zero order kinetics?
The rate of elimination of drug is constant and the rate is independent to the concentration of drug.
What factors affect metabolism?
Genetics Species Age Gender Disease states Inducer/inhibitor(food) Protein binding
Explain excretion of toxins
The toxins are excreted via the kidneys and this done by diffusion,active transport and filtration.
Larger toxin are excreted through the liver as faeces
