PSYC 2206 Chapter 2

Pharmacokinetics

Pharmacokinetics

The study of how a drug moves around the body.

Pharmacodynamics

The study of the biochemical and physiological effects of drugs and their mechanisms of action.

Absorption

The process by which a drug enters the bloodstream.

Bioavailability

The portion of the original drug dose that reaches its site of action.

Routes of Administration

The different ways in which drugs can be taken into the body.

Oral administration

Drugs taken by swallowing and absorbed by the stomach or intestines.

Injection

The process of introducing a drug into the body using a needle and syringe.

Subcutaneous injection

Injecting drugs under the skin.

Intramuscular injection

Injecting drugs within the muscle.

Intravenous injection

Injecting drugs directly into the veins and bloodstream.

Inhalation

Absorbing drugs through the lung's membranes.

Intranasal

Taking drugs in powdered form through the nose and absorbed by mucous membranes.

Sublingual

Placing drugs under the tongue to dissolve and be absorbed by an artery.

Drug Distribution

The process by which drugs are absorbed into the blood and distributed to their site(s) of action.

Blood-Brain Barrier (BBB)

A highly selective membrane that prevents substances from entering the extracellular space in the brain.

Drug Elimination

The process of removing drugs from the body through excretion or metabolism.

First-pass metabolism

The filtering of drugs by the liver before entering general circulation.

Dose-Effect Curve

A graphical representation of the relationship between drug dose and the size of an effect.

Effective dose (ED)

The dose at which a given percentage of individuals show a particular effect of a drug.

Lethal dose (LD)

The dose of a drug at which a given percentage of individuals die.

Therapeutic Index

A measure of drug safety calculated as LD50/ED50.

Drug Potency

The minimum effective dose of a drug.

Drug Efficacy

The effectiveness of a drug at producing a desired effect.

Tolerance

Reduced response to a drug after repeated administrations.

Cross-tolerance

Tolerance to a drug that results from tolerance to another drug or drugs.

Metabolic Tolerance

An increase in the rate of metabolizing a drug as a result of its regular use.

Functional Tolerance

Decreased behavioral effects of a drug as a result of its regular use.

Acute Tolerance

A type of functional tolerance that occurs within a course of action of a single drug dose.

Functional Tolerance

Drug effects may be greater during absorption than elimination, even though the blood concentration is the same.

Mechanisms of Functional Tolerance

Tolerance results from cellular processes in the body that attempt to compensate for the presence of the drug, an attempt to maintain homeostasis.

Regulation of receptors

Changes in the number of receptors that a drug is binding to or influencing.

Classical Conditioning

A learned association between a previously neutral stimulus after it has been paired with another stimulus that elicits an automatic response.

Unconditioned Stimulus

The drug is the unconditioned stimulus.

Unconditioned Response

Drug effects are the unconditioned response (salivation, drooling, vomiting).

Conditioned Stimulus

The stimuli that precedes the drug are the conditioned stimulus (tone, preparations for injection).

Conditioned Response

After multiple pairings, salivation and nausea become the conditioned response.

Compensatory Responses

Physiological responses that are opposite to the effect of the drug.

Compensatory Conditioned Response

The drug-predictive environmental conditioned stimulus comes to elicit conditioned responses that are opposite to the effects of the drug.

Classical Conditioning & Drug Tolerance

Tolerance that is maximally expressed in the presence of drug-predictive stimuli (environmental cues).

Operant Conditioning

Learning that is controlled by the consequences of the organism's behavior.

Self-administration Paradigm

When lever is pressed, drug dosage is delivered orally or through an infusion pump.

Rate of Responding

Measurement of the reinforcement value of drugs.

Reinforcement Value

Greater rates of responding indicate greater reinforcement value.

Drug Dependence

The rate of self-administration is an indication of a drug's potential for abuse.

Positive Reinforcement

Pleasurable effects of drugs are positive reinforcers.

Negative Reinforcement

Taking drugs to avoid withdrawal

Punishment

Consequences that deter drug use, but are less effective due to the temporal relationship between reinforcement and punishment.

Routes of Administration

Different ways drugs can be administered into the body.

Absorption and Distribution

How the route of administration impacts the absorption and distribution of drugs.

Lipid Solubility

A factor that affects the absorption and distribution of drugs.

Blood-Brain Barrier

A barrier that regulates the passage of substances from the blood into the brain.

Dose-Response Curve

A graph that shows the relationship between the dose of a drug and the response it produces.

Effective Dose

The dose of a drug that produces the desired effect.

Lethal Dose

The dose of a drug that causes death.

Therapeutic Index

The ratio of the lethal dose to the effective dose.

Drug Potency

The amount of drug required to produce a specific effect.