What is the explanation of the first level elimination noun?

The explanation of the first elimination noun is: it refers to the phenomenon that some drugs are administered through the gastrointestinal tract and are metabolized in the intestinal mucosa and liver before they are absorbed into the blood circulation, so that the amount of the original drug entering the blood circulation is reduced.

After some drugs are taken orally, after undergoing inactivated metabolism through the intestinal mucosa and liver, the amount of drugs entering the systemic circulation is reduced, and the efficacy is reduced. The phenomenon of different drug effects due to different routes of administration is of great significance in science.

Detailed interpretation:

There is no research evidence of any harm to humans from this physiological effect. The first pass eliminates the obvious drug and the oral bioavailability.

Low, compared with injectable administration, oral administration must be given at a higher dose to achieve a comparable effective plasma concentration.

Changes in the liver's ability to clear drugs can significantly affect plasma concentrations. After portacaval anastomosis, drugs can be directly introduced into the systemic circulation, resulting in increased drug bioavailability, but have little effect on drugs with no significant first-pass elimination and little difference between oral and injectable effective doses. Most of them are given intravenously, inhaled, sublingually, rectumally, and subcutaneously.

Avoidance of first-pass elimination of the drug.

The above content reference: Encyclopedia - the first level elimination.

First pass elimination: After oral drug absorption, it enters the liver through the portal vein, and some drugs are metabolized by liver enzymes when they enter the liver for the first time, and the amount of drugs that enter the systemic circulation is reduced.

After the first pass elimination process in the liver, the relative amount and speed of the amount of drug entering the systemic circulation and the actual dose of administration are called bioavailability. Some drugs are absorbed into the cells of the intestinal wall and some of them are metabolized. The first pass elimination is also known as the first pass metabolism or the first pass effect.

then quickly merged. > ways to avoid it. Change the route of administration. For example, oral nitroglycerin is metabolized by about 90% of the first-pass effect, so the efficacy is poor, and the first-pass effect is bypassed, while the sublingual is used, which is directly absorbed into the bloodstream by the sublingual mucosa, and the drug is less damaged.

Changlian chooses the appropriate time of administration, such as taking the drug while eating, which can reduce the metabolism of the drug in the liver and improve the bioavailability.

Doubling the first dose can counteract the metabolism of liver enzymes, and some drugs can also be taken once in the first daily dose.

In order to avoid the elimination of the first pass, pharmacists are also repeated experiments, painstakingly trying to find a way, some oral dosage forms are replaced with injection injections, transdermal patches, rectal suppositories or inhalation aerosols, etc., and some tablets can also avoid the first pass effect by changing the way they are taken.

For example, nitroglycerin tablets can be taken sublingually instead of swallowing, which can work quickly and efficiently. However, there are general exceptions, not all oral tablets have "first pass elimination", or it may be activation, and some prodrugs need to be metabolized by the liver to show pharmacological activity, such as prednisone, clopidogrel, cefuroxime ester.

Primer on absorption from the gastrointestinal tract.

Copy the venous system of the drug attack in the blood that reaches the whole body.

BAI must be du before circulation

If the liver has a strong metabolic energy or a large amount of bile excretion, the amount of effective drugs entering the systemic blood circulation is significantly reduced, and this effect is called first pass elimination.

Explanation of elimination.

eliminate;dispel;remove;clear up] so that it does not exist; Remove Eliminate Nuclear War Eliminate Every Mistake Explained in Detail (1).Remove and make non-existent. "Wei Shu Shizu Taiwu Ji I" :

The rebellion is eliminated, and the appearance is gradually obscured. Song Luyou's poem "Rainy Night": "The joy of youth is eliminated, and incense is burned on a rainy night and the Taoist scriptures are recited."

Qing Li Yu "Jade Scratching the Head, Rape Picture": If this generation is not eliminated, it will be difficult for my generation to be placed. Haoran "Sunny Day" Chapter 14:

The dark cloud in his heart has not been completely eliminated. ” 2).It is a pastime; Enjoy.

Yuan Xue Anfu "Yangchun Song": Clearing debts is bitter, and the bottle has wine and elimination. Yuan Anonymous's "Raising the Case and Raising the Eyebrows" The first fold:

If I suffer together and seek a place of honor, I am afraid that I will not be blessed. ”

Word decomposition Explanation of elimination elimination ā dissolve, dissipate: smoke disappears. Ablation (also known as "dissolving").

Disappear. Evanescent. Demise.

Depression. Negative. Digestion.

Extinguish, remove: eliminate. Exterminate.

Disinfect. Antiphlogistic. Spend your time there:

Spend the night. Spend the summer. Leisure.

Pastime. Kill (?.)Reduction, loss, consumption:

Explanation of elimination 除 ú remove: to remove harm. Expel.

Eradication. Shovel search pin grasp the world celebration except. Abrogate.

Exclude. Eliminate violence and peace. Change, transform:

The last day of the lunar year. Chinese New Year's Eve. Not counted:

Unless. Except. In arithmetic, dividing one number into another is the inverse of "multiplication".

Division. Steps: Step division.

Explanation of terms: also known as first elimination; If the liver has a strong metabolic ability or a large amount of bile excretion, the amount of effective drugs entering the systemic blood circulation is significantly reduced, and this effect is called Shouguan elimination.

Practical significance: Drugs with primary elimination (e.g., lidocaine, nitroglycerin) should not be taken orally, and can be changed to sublingual or rectal administration, or the dose can be increased. However, although praziquantel in schistosomiasis has been eliminated at the first level, it should also be administered orally, because the high concentration of the portal vein after oral absorption is conducive to killing the schistosomiasis parasitic here; After being metabolized by the liver, it can reduce systemic adverse reactions.

1. Define the first level elimination, also known as the first level metabolism and the first level effect.

It refers to the absorption of certain drugs from the gastrointestinal tract into the portal system, and when passing through mucositis and the liver, the amount of drugs entering the systemic circulation is reduced, and the process is called Shouguan elimination.

2 Oral administration is the most commonly used route of administration.

Drugs absorbed from the gastrointestinal tract into the venous system must pass through the liver before reaching the systemic blood circulation, and if the liver has a strong ability to metabolize it, or due to the large amount of bile excretion, the amount of effective drugs entering the systemic blood circulation is significantly reduced, and this effect is called Shouguan clearance.

Some drugs are absorbed into the cells of the intestinal wall and are metabolized partially, which also belongs to the first level of elimination. When gastrointestinal administration, a part of it can be excreted or metabolized in the lungs before reaching the site of action or target organs, which is also the first level of elimination, so the lungs have also become one of the first level elimination organs.

The first pass clearance is high, the bioavailability is low, and the amount of effective drug available to the body is small. In order to achieve the highest concentration, it is necessary to increase the dosage of the drug, but it may cause toxic reactions of metabolites.

If the liver has a strong ability to metabolize it or excretes a large amount of bile, the amount of effective drugs entering the systemic blood circulation is significantly reduced, and this effect is called first pass elimination.

If the liver has a strong metabolic ability or a large amount of bile excretion, the amount of effective drugs entering the systemic blood circulation is significantly reduced, and this effect is called Shouguan elimination.

Explanation of the term of the first level elimination: the drug absorbed from the gastrointestinal tract into the entry venous system must pass through the liver before reaching the systemic blood circulation, and if the liver has a strong metabolic ability or a large amount excreted by bile, the amount of effective drugs entering the systemic blood circulation is significantly reduced.