Lääkejakaumaan

Lääkejakaumaan refers to the distribution of a drug within the body. It describes how a drug moves from the bloodstream into various tissues and organs, and how it is subsequently eliminated. This process is a crucial aspect of pharmacokinetics, the study of what the body does to a drug. Understanding a drug's distribution is vital for determining appropriate dosage, frequency of administration, and potential toxicity.

Several factors influence drug distribution. These include blood flow to different tissues, the drug's ability to cross cell membranes, its binding to plasma proteins, and its solubility in lipids and water. Highly perfused organs like the liver, kidneys, and brain generally receive higher concentrations of a drug initially. The blood-brain barrier, for instance, restricts the passage of many substances into the central nervous system, affecting the distribution of certain drugs.

The volume of distribution (Vd) is a pharmacokinetic parameter that quantifies the extent to which a drug is distributed throughout the body. It is not a true physiological volume but rather a theoretical volume representing the fluid that would be required to contain the total amount of drug in the body at the same concentration as in the plasma. A high Vd suggests that a drug distributes widely into tissues, while a low Vd indicates it is primarily confined to the bloodstream. Factors like body weight, age, and disease states can alter a drug's distribution pattern.