Pharmacokinetics & pharmacodynamics

what is pharmacokinetics?

the study of drug movement in the body

what are the four processes of pharmacokinetics?

absorption, distribution, metabolism, excretion

what is the absorption process of pharmacokinetics?

the movement of a drug from its site of administration to the blood

what is determined by the rate of absorption and amount of absorption?

the intensity and speed of a drug

what factors affect drug absorption?

drug solubility, ionization and blood flow

what is the advantage of intravenous route?

provides fast and complete drug absorption

what are the disadvantage of intravenous drug route?

irreversible, expensive, infection

what is distribution?

movement of drug through the bloodstream

what factors affect drug distirbution?

blood flow, hypoalbuminemia, tissue binding, competition for binding site

How does hypoalbuminemia affect drug distribution?

low albumin leads to increased free drug flow in the blood

To cross the blood-brain barrier toa significant degree, what characteristics must a drug possess?

the drug has to be lipid soluble

what is metabolism?

the chemical inactivation of drugs

what is the major site of metabolism?

liver

what enzyme is responsible for drug metabolism?

cytochromes P45

what is the primary consequence of the “first pass effect” for certain oral medications?

inactivation by the liver

what is excretion?

the removal of drugs from the body

what are the three processes of drug excretion?

glomerular filtration, passive reabsorption, active transport

what factors modify renal excretion?

pH ionization, age, renal function

what’s a drug’s half-life?

the time required for the amount of drug in the body to be reduced by 50%

what is the therapeutic range?

plasma drug level between the minimum effective and toxic concentration

what is the latrogenic effect?

undesired or unintentional condition caused by medical treatment

what is an Idiosyncratic response?

abnormal or opposite drug effect

what is an antagonist drug?

A drug that binds to a receptor but does not activate it

what is an agonist drug?

a drug that activates a receptor and produces a response

what are the therapeutic consequences of drug metabolism?

increased renal drug excretion, therapeutic action, increased or decreased toxicity

what is some special consideration in drug metabolism?

age, nutritional status, competition among drugs

what is pharmcodynamics?

the study of a drugs does to the body and their effect

what is a dose-response relationship?

the relationship between the size of dose administered and the effect it produced

What does the dose-response relationship determine?

minimum dose, maximum response and dosage adjustment

What happens as drug dosage increases?

the response becomes progressively larger

According to the general principles of drug action, which of the following is a true statement regarding how drugs affect cells?

drugs alter the rate of existing cellular function

what is the maximum efficacy?

the largest effect that a drug can produce

what is the produce of the Maximal efficacy of a drug?

match the intensity of a drug’s effect with patient’s need

what is relative potency?

the dosage needed to produce an effect

what are the four primary receptor families?

cell membrane enzyme, ligand ion, G protein and transcription factor

why does receptor selectivity matter?

there are less side effects

What is the Modified occupancy theory?

the strength between a drug and a receptor determines how strongly it activates a receptor

what is the simple occupancy theory?

A drug needs identical receptor to produce an effect

what is a noncompetitive antagonist?

a drug that irreversibly binds to receptors and reduce maximal response

what is competitive antagonist?

A drug that reversibly compete with agonist for receptor binding

What is a partial agnosit?

A drug with moderate intrinsic activity that can act as an agonist or antagonist

what happens with a continuous exposure to an agonist and antagonist?

desensitization, downregulation, hypersensitivity

A drug with a high therapeutic index is generally considered safer because?

there is a wide margin between the ED50 and LD50

What is Adverse Drug Reaction?

unintended and harmful effect at a normal dose

What is a side effect?

An unavoidable effect of a drug at normal dose