Which factor can influence how long a drug stays in a client's system?

The duration a drug remains in a client’s system is significantly influenced by the client's liver enzyme activity. The liver is the primary organ responsible for drug metabolism, and liver enzymes, particularly those in the cytochrome P450 family, play a crucial role in the biotransformation of drugs. When liver enzyme activity is high, drugs may be metabolized and eliminated more quickly, whereas low enzyme activity can prolong the presence of a drug in the bloodstream, leading to increased effects or side effects.

Other factors like age, diet, and exercise can also influence pharmacokinetics, but liver enzyme activity has a direct and powerful effect on the metabolism of many drugs. For instance, certain diets may impact enzyme levels, and age can affect liver function, but the intrinsic activity of these enzymes is a more direct determinant of how quickly a drug is processed and cleared from the body.