Conditions and Diseases

What is first pass hepatic metabolism?

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Answered 2009-07-24 02:46:14

The first-pass hepatic metabolism of a number of important therapeutic agents is inconsistent with traditional models that assume that the hepatic extraction ratio of a drug is constant in each individual (independent of the concentration of drug in the hepatic sinusoidal blood and also independent of the history of exposure to the drug). In this review, the authors examine the first-pass metabolism of five "problematic drugs" (propranolol, lidocaine, propafenone, verapamil, and nitroglycerin). Each of these compounds has unique facets to its hepatic clearance and pharmacokinetics as well as striking similarities. Selected aspects of first-pass metabolism are reviewed, and a theory that may explain some of the unusual behavior of the four lipophilic bases (propranolol, lidocaine, propafenone, and verapamil) is presented. Finally, the unusual and variable clearance of nitroglycerin is discussed. D Lalka, RK Griffith, and CL Cronenberger

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What is second pass hepatic metabolism?

the effect after 1st pass effect which is undergone by beta glucoronidase enzyme in small intestine .

What is first pass metabolism?

First pass metabolism is when some substance (usually a drug) is altered before it can reach its site of action.Often, drugs that are taken orally are brought by the digestive system into the hepatic portal vein into the liver, which does lots of metabolism. If the same drug could have been administered intravenously (that is, through an injection or line), it would not undergo first pass metabolism because it has bypassed the liver to get into circulation. Eventually, the drug will probably be completely metabolized either way, it's just that the oral route reaches circulation more metabolized than something injected.

Why can't you chew or swallow suboxone?

Buprenorphine (Brand name Subutex and Suboxone) is not administered orally due to very high first-pass metabolism. The first-pass effect (also known as first-pass metabolism or presystemic metabolism) is a phenomenon of drug metabolism whereby the concentration of a drug is greatly reduced before it reaches the systemic circulation.

How do nutrients pass from the digestive system to the circulatory system?

They go first to the liver via the hepatic portal vein.

What are the factors affecting bioavailability of orally administered drug?

Many factors can contribute to affect the bioavailability of the orally administered drugs. Briefly, these includes gastric emptying rate, intestinal transit time, hepatic first pass metabolism, and gastrointestinal and hepatic blood flow etc. apart from these factors, disease conditions, diet and dosage form also contribute in alteration of the bioavailability of the drugs.

What is the hepatic system?

The hepatic (portal) system refers to the blood vessels that carry blood from the intestines, stomach, pancreas and spleen to the liver. Blood containing nutrients or drugs absorbed from the intestine is transported by the hepatic portal system to the liver for metabolism before distribution to the rest of the body.

How does a liver defend your body?

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Hepatic microsomal induction, you might mean, is as it is, induction of hepatic microsomal enzymes. These microsomal enzymes are found in the liver and are responsible for the metabolism of drugs that we take in. There are some drugs though, that can increase the activity of these enzymes. Some examples are: Dicoumarol Disulfiram Isoniazid Cimetidine Chloramphenicol Sulfonamides If these drugs are taken in along with another, the metabolism of the other drug will be decreased, resulting in an increased half life.

Where do the nutrients that pass through villi go?

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What has the author Xiu-Yan Silvia Xie written?

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You may not pass a breathalyzer after not drinking for 10 hours. Each person's metabolism is different, some could pass and some will not.

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