What is the first elimination?

First-pass elimination (first-pass elimination) Drugs absorbed from the gastrointestinal tract into the portal vein system must pass through the liver before reaching the systemic blood circulation. If the metabolic capacity of the liver is strong, or the bile excretion is large, the amount of effective drugs entering the systemic blood circulation will be significantly reduced. This effect is called first-pass elimination.

Some drugs are absorbed by intestinal wall cells and some drugs are metabolized, which is the first time to be eliminated. First pass elimination is also called first pass metabolism or first pass effect. Injection, sublingual and rectal administration can avoid liver metabolism.

The obvious drugs for the first time are nitroglycerin and propranolol. , generally not suitable for oral administration or need to be adjusted.

Extended data:

Related:

The first-pass effect means that oral drugs first enter the portal vein system of the liver after being absorbed in the gastrointestinal tract. When some drugs pass through intestinal mucosa and liver, some drugs can be inactivated by metabolism, which reduces the amount of drugs entering the human circulation and reduces the efficacy.

Chinese Name: First Pass Effect

Avoidance measures: sublingual and rectal administration

Nickname: the first level effect

Results: The dosage decreased and the curative effect decreased.

Baidu Encyclopedia-First Pass Elimination

Baidu Encyclopedia-First Pass Effect