lääkeainemetaboliaan

Lääkeainemetabolia, also known as drug metabolism, refers to the series of chemical transformations that drugs undergo within the body. These transformations are primarily catalyzed by enzymes, with the liver being the main site of drug metabolism. However, other tissues, including the intestines, lungs, kidneys, and skin, can also contribute. The primary goal of drug metabolism is to convert lipophilic (fat-soluble) drugs into more hydrophilic (water-soluble) metabolites, facilitating their excretion from the body, typically via urine or bile.

Metabolism is generally divided into two phases. Phase I reactions involve functionalization, often introducing or exposing polar functional groups like hydroxyl, amino, or carboxyl groups. Common Phase I reactions include oxidation, reduction, and hydrolysis, frequently mediated by the cytochrome P450 (CYP) enzyme superfamily. These reactions can sometimes result in metabolites that are still pharmacologically active, or even more active than the parent drug.

Phase II reactions, also known as conjugation reactions, involve the attachment of endogenous polar molecules to the drug or its Phase I metabolite. These conjugates are typically more water-soluble and readily excreted. Common conjugation reactions include glucuronidation, sulfation, acetylation, and methylation. The enzymes responsible for Phase II reactions are diverse and include UDP-glucuronosyltransferases (UGTs), sulfotransferases (SULTs), and N-acetyltransferases (NATs).

The rate and pathways of drug metabolism can vary significantly among individuals due to genetic factors, age, disease states, and interactions with other drugs or substances. Understanding lääkeainemetabolia is crucial for determining appropriate drug dosages, predicting drug interactions, and optimizing therapeutic outcomes.