What factors influence drug distribution in the body?

Blood flow to tissues is a critical factor that influences drug distribution in the body. Drugs are carried to various tissues and organs via the bloodstream, so the rate and volume of blood flow to a specific area directly affect how quickly and effectively a drug diffuses out of the vessels and reaches the target site. Tissues with higher blood flow, such as the liver, kidneys, and brain, generally receive drugs more rapidly compared to areas with lower blood flow, such as adipose tissue.

Additionally, factors such as tissue permeability and the drug's physicochemical properties (like lipophilicity, ionization, and molecular size) also play essential roles in distribution. However, among the listed factors, blood flow stands as the primary determinant. It underscores why drugs can have different effects in various tissues and why some organs may be targeted more effectively than others during therapy.

While body weight, age, and dietary habits can indirectly influence drug distribution through alterations in metabolic rates, body composition, and overall physiological conditions, they do not have the direct, immediate impact on distribution that blood flow does.