Pharmacokinetics Flashcards
This branch of pharmacology is also
concerned with a drug’s onset of action, peak concentration level, and duration
of action
Pharmacokinetics
Kinetics refers to movement. Pharmacokinetics deals
with a drug’s actions as it moves through the body. Therefore, pharmacokinetics discusses how a drug is:
Is also the Drug Equilibrium.
⚬ Absorbed (taken into the body)
⚬ Distributed (moved into various tissues)
⚬ Metabolized (changed into a form that can be excreted)
⚬ Excreted (removed from the body).
On a cellular level, drugs are absorbed by several means—primarily through (Answer) and (Answer) transportation.
Passive and Active transportation
Distribution of an absorbed drug within the body depends on
several factors:
⚬ blood flow
⚬ solubility
⚬ protein binding
is the process by which the body changes a drug from its dosage form to a more water-soluble form that can then be excreted.
Drug metabolism (or biotransformation)
Most drugs are metabolized into (Answer) metabolites (products of metabolism), which
are then excreted.
Inactive
What are the different ways drugs can be excreted and leave the body (except Kidneys)
- Lungs
- Exocrine (sweat, salivary, or mammary) glands
- Skin
- Intestinal tract.
The amount of drug that is needed to cause a therapeutic effect
Critical Concentration
A higher dose than that usually used for treatment to reach critical concentration quickly
Loading Dose
Process of Dynamic Equilibrium
- Absorption from the site of entry
- Distribution to the active site
- Biotransformation (metabolism) in the liver
- Excretion from the body
Refers to what happens to a drug from the time it is introduced to the body until it reaches the circulating fluids and tissues
Absorption
Drug absorption is influenced by (Answer)
Route of Administration
Processes of Absorption
Passive Diffusion
Active Transportation
Filtration
- Major process through which drugs are absorbed into the body
- Occurs across a concentration gradient
- Movement from an area of greater concentration to lower concentration
Passive Diffusion
- Process that uses energy to actively move a molecule across a cell membrane
Active Transport
- Involves movement through pores in the cell membrane either down a concentration gradient or as a result of the pull of plasma protein
Filtration
What are the considerations involved in Pharmacokinetics?
- onset of drug action (how long it will take to see the beginning of the
therapeutic effect) - drug half life
- timing of the peak effect (how long it
will take to see the maximum effect of the drug)
*duration of drug effects (how long the patient will experience the drug effects),
*metabolism or biotransformation of the drug,
*site of excretion.
involves the study of absorption, distribution, metabolism
(biotransformation), and excretion of drugs
Pharmacokinetics
Most drugs are bound to some extent to proteins in the blood
to be carried to the circulation.
Protein Binding
Is a protective system of cellular activity that keeps
many things away from the CNS.
Blood Brain Barrier
The process by which drugs are changed into new, less active chemicals.
METABOLISM (BIOTRANSFORMATION)
Drugs that are taken orally are usually absorbed from the small
intestine directly into the portal venous system. The portal veins
deliver these absorbed molecules into the liver, which immediately
transforms most of the chemicals delivered to it by a series of liver
enzymes. These enzymes break the drug into metabolites, some of
which are deactivated and can be readily excreted from the body.
First Pass effect
Is the removal of drug from the body
Excretion
What kind of filtration is excreted through the kidneys?
Glomerular filtration
is the time it takes for the amount of drug in the body to decrease to one half of the peak level it previously achieved.
Half life
This information is important in determining the appropriate timing for a drug dose or determining the duration of a drug’s effect on the body
Half life
Factors affecting drug effects
- Weight
- Age
- Gender
- Physiologic factors
- Pathological factors
- Genetic factors
- Immunological Factors
- Psychological Factors
- Environmental Factors
