2. Distribution

Distribution

The movement of a drug from the bloodstream into body tissues.

Albumin

The plasma protein that most commonly binds drugs.

Protein-bound drug

The drug portion that is attached to plasma proteins and cannot interact with receptors.

Free drug (unbound drug)

The drug portion that is available to leave the bloodstream and produce a pharmacologic effect.

Highly protein-bound drugs

Drugs that are approximately 90% or more bound to plasma proteins.

Weakly protein-bound drugs

Drugs that are less than 10% bound to plasma proteins.

Blood flow

A factor that influences drug distribution by determining how quickly a drug reaches a tissue.

Tissue affinity

The attraction or tendency of a drug to accumulate in a particular tissue.

Protein binding

The process by which drugs attach to plasma proteins in the bloodstream.

Hypoalbuminemia

A condition in which albumin levels are decreased, increasing the amount of free drug.

Albumin level

The plasma protein level that should be assessed before administering highly protein-bound drugs.

Drug toxicity

The clinical result that may occur when free drug levels become excessively high.

Liver disease

A disease affecting the liver that can reduce albumin production.

Kidney disease

A disease affecting the kidneys that can reduce plasma protein levels.

Malnutrition

A nutritional condition that may decrease albumin levels and increase free drug concentration.

Hypoalbuminemia

Older adults with low albumin levels are said to have this condition.

Protein-binding sites

When two highly protein-bound drugs are given together, they may compete for these locations.

Drug displacement

The process in which one drug pushes another drug off its protein-binding site.

Drug accumulation

The result of drug displacement that increases the concentration of free drug in the bloodstream.

Placenta

The membrane through which drugs can pass from the mother to the fetus.

First trimester

Drug exposure during this trimester has the highest risk of causing spontaneous abortion.

Second trimester

Drug exposure during this trimester may cause teratogenesis.

Third trimester

Drug exposure during this trimester may alter fetal growth and development.

Risk-benefit ratio

The principle that compares the potential benefits of a drug with its potential harms during pregnancy.

Breast milk

The fluid through which drugs can be transferred from the mother to the nursing infant.

Nurse

The healthcare professional responsible for teaching breastfeeding mothers to consult a provider before taking medications.

Free drug

The type of drug that can leave the blood vessel and bind to tissue receptors.

Protein-bound drug

The type of drug that remains temporarily stored in the bloodstream because it is attached to protein.

Distribution

The pharmacokinetic phase discussed in this lesson.

Pharmacologic effect

The interaction between a drug and its receptor that produces a pharmacologic response.

Free drug

A decrease in plasma protein levels causes an increase in the amount of this type of drug.

Toxicity

The major concern when two highly protein-bound drugs are administered concurrently.

Serum albumin

The laboratory value most closely associated with plasma protein binding of many drugs.

Monitor albumin and protein levels

The nursing implication that requires monitoring protein and albumin levels before administering certain medications.

They cannot bind to tissue receptors

The main reason protein-bound drugs are considered inactive.