The liver is the principal site of drug metabolism (for review, see ). Although metabolism typically inactivates drugs, some drug metabolites are pharmacologically active—sometimes even more so than the parent compound.
What is the major organ of drug metabolism?
Most drugs must pass through the liver, which is the primary site for drug metabolism. Once in the liver, enzymes convert prodrugs to active metabolites or convert active drugs to inactive forms. The liver’s primary mechanism for metabolizing drugs is via a specific group of cytochrome P-450 enzymes.
Which organ or tissue is most responsible for drug metabolism?
Many sites in the body are involved in drug metabolism including the gastrointestinal mucosa, lungs, kidneys, or circulating enzymes in plasma such as esterases. However, the liver is quantitatively and qualitatively the most important site of drug metabolism.
What are the two most important organs for drug metabolism?
The principal organs of drug metabolism are the liver and (for orally taken drugs) the small intestine.
Which of the following organs is a main site for the metabolism of drugs?
Excretion involves elimination of the drug from the body, for example, in the urine or bile. Most drugs must pass through the liver, which is the primary site for drug metabolism.
What are the two major goals of drug metabolism?
The purpose of metabolism in the body is usually to change the chemical structure of the substance, to increase the ease with which it can be excreted from the body. Drugs are metabolized through various reactions including: Oxidation. Reduction.
What factors affect metabolism of a drug?
Individual drug metabolism rates are influenced by genetic factors, coexisting disorders (particularly chronic liver disorders and advanced heart failure), and drug interactions (especially those involving induction or inhibition of metabolism).
What happens if a drug is not metabolized?
If your body metabolizes a drug too slowly, it stays active longer, and may be associated with side effects. Because of this, your doctor may characterize you as being one of four metabolizer types, with respect to a specific enzyme. Poor metabolizers have significantly reduced or non-functional enzyme activity.
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 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.
What factors can affect drug metabolism in the elderly?
Aging results in a number of significant changes in the human liver including reductions in liver blood flow, size, drug-metabolizing enzyme content, and pseudocapillarization. Drug metabolism is also influenced by comorbid disease, frailty, concomitant medicines, and (epi)genetics.
What drug is excreted in saliva?
Compounds usually excreted in saliva are Caffeine, Phenytoin, and Theophylline. The salivary elimination of various compounds, like mercury derivatives, has been known for a long era and it is admitted that the salivary concentration of liposoluble drugs is the reflection of their plasma concentration in free form.
What is the difference between a drug and a drug metabolite?
A drug metabolite is a byproduct of the body breaking down, or “metabolizing,” a drug into a different substance. … Therefore, the presence of a drug metabolite can be a reliable indicator that a person used the “parent” drug of that metabolite. Some metabolites stay in the body much longer than the parent drug.
How are drugs metabolised in the body?
Drugs can be metabolized by oxidation, reduction, hydrolysis, hydration, conjugation, condensation, or isomerization; whatever the process, the goal is to make the drug easier to excrete. The enzymes involved in metabolism are present in many tissues but generally are more concentrated in the liver.
How are drugs broken down in the body?
The vast majority of medications are taken orally and are broken down within the gastrointestinal tract. Once the medication arrives, it is broken down by stomach acids before it passes through the liver and then enters the bloodstream.
What is hepatic metabolism of drugs?
The constellation of chemical alterations to drugs or metabolites that occur in the liver,carried out by microsomal enzyme systems, which catalyze glucuronide conjugation, drug oxidation, reduction and hydrolysis.