What is second pass metabolism?

What are the 2 phases of metabolism?

Metabolism is often divided into two phases: Phase 1 metabolism involves chemical reactions such as oxidation (most common), reduction and hydrolysis. There are three possible results of phase 1 metabolism.

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 are the three phases of metabolism?

The metabolism of xenobiotics is often divided into three phases:- modification, conjugation, and excretion.

What is meant by first pass metabolism?

The first pass effect is a phenomenon in which a drug gets metabolized at a specific location in the body that results in a reduced concentration of the active drug upon reaching its site of action or the systemic circulation.

IT IS INTERESTING:  Who has the lowest BMI in the world?

Where does Phase 1 and 2 metabolism occur?

The liver is the primary site for metabolism. Liver contains the necessary enzymes for metabolism of drugs and other xenobiotics. These enzymes induce two metabolism pathways: Phase I (functionalization reactions) and Phase II (biosynthetic reactions) metabolism.

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.

Where does Phase 2 of drug metabolism occur?

Glucuronidation, the most common phase II reaction, is the only one that occurs in the liver microsomal enzyme system. Glucuronides are secreted in bile and eliminated in urine. Thus, conjugation makes most drugs more soluble and easily excreted by the kidneys.

What are the two routes by which drugs can be eliminated into the system?

Renal excretion is the most common route of drug elimination. However, many drugs are excreted into bile via the liver and some volatile substances (primarily gaseous anesthetics) can be excreted via the lungs.

What is oxidation in metabolism?

Listen to pronunciation. (OK-sih-DAY-tiv meh-TA-buh-lih-zum) A chemical process in which oxygen is used to make energy from carbohydrates (sugars). Also called aerobic metabolism, aerobic respiration, and cell respiration.

What are the three main purpose of metabolism?

The three main purposes of metabolism are the conversion of food/fuel to energy to run cellular processes, the conversion of food/fuel to building blocks for proteins, lipids, nucleic acids, and some carbohydrates, and the elimination of nitrogenous wastes.

IT IS INTERESTING:  Can you be sacked for being overweight?

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 is the final stage of metabolism?

Catabolism is the break down of complex molecules. Catabolism is the breakdown of complex substances to their constituent parts (glucose, amino acids and fatty acids) which form substrates for metabolic pathways.

What happens after first pass metabolism?

Drug Absorption

The drug is absorbed from the GI tract and passes via the portal vein into the liver where some drugs are metabolised. Sometimes the result of first pass metabolism means that only a proportion of the drug reaches the circulation. First pass metabolism can occur in the gut and the liver.

How do I overcome my first pass metabolism?

Bypassing First Pass Metabolism

Two ways to bypass first pass metabolism involve giving the drug by sublingual and buccal routes. The drugs are absorbed by the oral mucosa in both methods. In sublingual administration the drug is put under the tongue where it dissolves in salivary secretions.

What routes bypass the first pass effect?

Intravenous (IV)

Injection straight into the systemic circulation is the most common parenteral route. It is the fastest and most certain and controlled way. It bypasses absorption barriers and first-pass metabolism.

Health PRO