How does the body metabolize drugs?

The body metabolises drugs primarily through the liver, using enzymes to break them down into simpler substances.

The process of drug metabolism, also known as biotransformation, is a complex one that involves several stages. It primarily occurs in the liver, which is the body's main organ for detoxification. However, other organs like the kidneys, lungs, and intestines also play a role. The goal of drug metabolism is to make the drug more soluble so it can be easily excreted from the body.

The first stage of drug metabolism is called Phase I. This involves chemical reactions such as oxidation, reduction, and hydrolysis. The liver's enzymes, particularly those from the cytochrome P450 family, play a crucial role in these reactions. They modify the drug's chemical structure, often making it more polar and therefore more soluble in water. However, some drugs may become active or toxic during this phase.

Phase II of drug metabolism is known as conjugation. In this stage, the drug or its metabolites from Phase I are combined with an endogenous substance, such as glucuronic acid, sulphate, or glycine. This process further increases the drug's water solubility, preparing it for excretion.

The metabolised drug is then transported to the kidneys, where it is filtered out of the blood and excreted in urine. Some drugs are also excreted through sweat, saliva, breast milk, or breath.

It's important to note that the rate of drug metabolism can vary greatly among individuals. Factors such as age, genetics, diet, and the presence of other drugs can influence how quickly a drug is metabolised. This is why the same dose of a drug can have different effects on different people. Understanding drug metabolism is therefore crucial in the field of pharmacology, as it helps to predict drug interactions, side effects, and individual responses to medication.