Which process is responsible for the breakdown of drugs in the body?

Metabolism is the process responsible for the breakdown of drugs in the body. This complex set of chemical reactions occurs primarily in the liver, where enzymes modify drugs into more water-soluble compounds that can be easily excreted. The metabolic processes can include both the activation of prodrugs (substances that become active following metabolic conversion) and the detoxification of active drugs.

During metabolism, drugs are chemically altered, which often leads to their inactivation or conversion into metabolites that may have different pharmacological effects. This process ensures that the drug's activity in the body is controlled, allowing for the proper therapeutic effect while reducing the risk of toxicity.

The other processes listed have different functions: absorption refers to the process by which drugs enter the bloodstream, distribution is about how drugs are transported throughout the body after entering the circulation, and secretion pertains to the elimination of drugs from the body, often through urine or bile. Each of these plays a critical role in pharmacokinetics but does not specifically address the breakdown of drugs as metabolism does.