In short, “metabolism of drugs” is a form of biotransformation which happens to drugs in a body, whereas “biotransformation” is a more general term which applies equally well to the actions of a disembodied enzyme digesting an oil slick.
What is the best definition of biotransformation?
biotransformation. the chemical alteration of the drug molecule by the cells of the animal.
What does it mean to metabolize a drug?
Drug metabolism is the chemical alteration of a drug by the body. (See also Introduction to Administration and Kinetics of Drugs.) Some drugs are chemically altered by the body (metabolized).
What is metabolism in pharmacokinetics?
Metabolism describes the chemical reactions that change drugs into compounds which are easier to eliminate. The products of these chemical reactions are called metabolites. … Producing metabolites which consist of polar molecules means that they can be excreted in body fluids such as urine and bile.
What is metabolism in toxicology?
Metabolism or biotransformation of toxicants by the body is an “attempt to detoxify.” In some instances, metabolized xenobiotic agents are more toxic than the original compound. These reactions, catalyzed by hepatic enzymes, generally convert foreign compounds to derivatives for Phase II reactions. …
What is biotransformation and where in the body does it occur?
Primary Biotransformation Site: The Liver
Since the liver is the primary site for biotransformation , it is also potentially vulnerable to the toxic action of a xenobiotic that is activated to a more toxic compound.
What is first pass metabolism of drug?
The first-pass metabolism or the first-pass effect or presystemic metabolism is the phenomenon which occurs whenever the drug is administered orally, enters the liver, and suffers extensive biotransformation to such an extent that the bioavailability is drastically reduced, thus showing subtherapeutic action (Chordiya …
What are the phases of drug metabolism?
Drug metabolism reactions comprise of two phases: Phase I (functionalization) reactions such as oxidation, hydrolysis; and Phase II (conjugation) reactions such as glucuronidation, sulphate conjugation. Oxidation reactions are the most common and vital.
What causes slow drug metabolism?
Underlying health conditions can also influence your drug metabolic rate. Some concerning ones are chronic liver disorders, kidney dysfunction, or advanced heart failure. Drug and Food Interactions. CYP450 enzymes can be impacted by the foods you eat and other drugs you take.
What are the four stages of drug metabolization?
The method by which a drug is administered, along with other factors, determines the speed of onset of effects. Drugs undergo four stages within the body: absorption, distribution, metabolism, and excretion.
Why does first pass metabolism occur?
The drug is absorbed from the GI tract and passes via the portal vein into the liver where some drugs are metabolised. … For example, first pass metabolism occurs in the gut for benzylpenicillin and insulin and in the liver for propranolol, lignocane, chloromethiasole and GTN.
What is Phase 2 drug metabolism?
Phase I reactions of drug metabolism involve oxidation, reduction, or hydrolysis of the parent drug, resulting in its conversion to a more polar molecule. Phase II reactions involve conjugation by coupling the drug or its metabolites to another molecule, such as glucuronidation, acylation, sulfate, or glicine.
What is the process of metabolism?
Metabolism refers to all the chemical processes going on continuously inside your body that allow life and normal functioning (maintaining normal functioning in the body is called homeostasis). These processes include those that break down nutrients from our food, and those that build and repair our body.
What Toxicology means?
Toxicology is traditionally defined as “the science of poisons.” Over time, our understanding of how various agents can cause harm to humans and other organisms has increased, resulting in a more descriptive definition of toxicology as “the study of the adverse effects of chemical, physical, or biological agents on …
What are metabolic activities?
Metabolism is a balancing act involving two kinds of activities that go on at the same time: building up body tissues and energy stores (called anabolism) breaking down body tissues and energy stores to get more fuel for body functions (called catabolism)
Which of the following is the correct decreasing order of drug metabolism?
Metabolism by other organs is very less because they have very low quantity of enzymes present in them. Thus the order is liver > lungs > kidneys > intestine > placenta > adrenals > skin. Explanation: The enzymes are divided into 2 categories namely microsomal and non-microsomal.