PHARMACOKINETICS Flashcards
AND PHARMACODYNAMICS
how the drug affects the body
Pharmacodynamics
how the body acts on the drug
Pharmacokinetics
is the study of the interactions
between the chemical
components of living systems
and the foreign chemicals,
including drugs that enter those
systems.
PHARMACODYNAMICS
Drugs usually work in one of four ways: RIDI
- To replace as substitutes for
missing chemicals - To increase certain
cellular activities - To depress cellular
activities - To interfere with functioning of foreign
cells, such as invading
microorganisms or neoplasms leading
to cell death
are medications used to treat cancer.
These drugs work by targeting and killing cancer cells, often by interfering with their growth and division processes.
chemotherapeutic agents
Specific areas on cell
membranes
Receptor Sites
react with certain
chemicals to cause an effect
within the cell
Receptor Sites
what breaks down the
reacting chemicals and open
the receptor site for further
stimulation?
Enzymes
Interact directly with receptor sites to cause the same activity that natural chemicals would cause at that site
Agonists
Prevent breakdown of natural chemicals that are
stimulating the receptor site
Inhibitors
React with receptor sites to block normal stimulation, producing no effect
Competitive Antagonist
React with specific receptor sites on a cell and by
reacting there prevent the reaction of another
chemical with a different receptor site on that cell
Non Competitive Antagonist
Drugs also can cause their effects by interfering with the
Enzyme System
act as catalysts for various chemical
reactions
Enzyme system
Enzyme systems work in a what fashion?
cascade fashion
what do u call when with one
enzyme activating another, and then that enzyme activating another, until a cellular reaction eventually occurs
cascade fashion
The ability of a drug to
attack only those
systems found in foreign
cells
Selective Toxicity
involves the study of absorption, distribution, metabolism
(biotransformation), and excretion of drugs
Pharmacokinetics
In clinical practice, pharmacokinetic considerations includes…ODTDMS
- onset of drug action
- drug half life
- timing of the peak effect
- duration of drug effects
- metabolism
- Site of excretion
(how long it will take to see the beginning of the
therapeutic effect),
Onset of drug action
(how long it
will take to see the maximum effect of the drug)
timing of peak effect
(how long the patient will experience the drug effects)
duration of drug effect
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
Dynamic Equilibrium; processes:
- Absorption from the site of entry
- dISTRIBUTION TO THE ACTIVE SITE
- biotransformation 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 the
route of administration
Process of Absorption:
- Passive Diffusion
- Active Transport
- Filtration
Major process through which drugs are absorbed into the body
Passive diffusion
Occurs across a concentration gradient
Passive diffusion
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 plasmaproteins
filtration
What is the primary function of plasma proteins in the process of filtration?
maintain oncotic pressure
Route of Absorption
- Intravenous
- Intramuscular
- Intradermal
- PO oral
- PR rectal
- Mucous Membrane
- Topical (skin)
- Inhalation
Involves the movement of a drug to the body’s
tissues
DISTRIBUTION
Factors that affect drug distribution:
- Drug’s lipid solubility and ionization
- Perfusion of the reactive tissue
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
what type of drugs are more likely to pass through the blood
brain barrier?
highly lipid soluble
Many drugs pass through the
_______ and affect the
developing fetus in pregnant
women
Placenta and Breast Milk
The process by which drugs are changed
into new, less active chemicals
Biotransformation (metablism)
Drugs that are taken orally are usually absorbed from the ______ directly into the ______ system.
small intestine, portal venous system
The portal veins deliver these absorbed molecules into the _____, which immediately transforms most of the chemicals delivered to it by a _______.
liver, series of liver enzymes
what do u call this effect when 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.
FIRST PASS EFFECT
Is the removal of a drug from the body.
EXCRETION
ROUTES FOR EXCRETION:
Skin, saliva, lungs, bile and feces
Excreted by the kidneys through 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
FACTORS INFLUENCING DRUG
EFFECTS: WAG PP GIPETC
- weight
- Age
- Gender
- Physiologic Factor
- Pathological Factor
- Genetic Factor
- Immunological factors
- Psychological factor
- Environmental Factor
- Tolerance
- Cumulation
new area of study that explores the unique
differences in response to drugs that each individual
possesses based on genetic makeup.
Pharmacogenomics
When two or more drugs or substances are taken together, there is a possibility that an interaction can occur,
causing unanticipated effects in the body.
Interactions
Types of Interactions:
- Drug to Drug or Drug to Alternative Therapy Interactions
- Drug to Laboratory Test Interaction
- Drug to Food Interaction
Drug to Drug or Drug to Alternative Therapy Interactions
- At the site of absorption
- During distribution
- During metabolism
- During excretion
- At the sire of action
administration of a particular drug may alter results of tests that are done on various chemical levels or reactions as part of a diagnostic study
Drug to Laboratory Test Interaction
Some foods increase acid production, speeding the breakdown of the drug molecule and preventing absorption and distribution of the drug
Drug to Food Interaction
All drugs are potentially dangerous. Even though chemicals are carefully screened and tested in animals and in people before they are approved for sale, drug products often cause unexpected or unacceptable reactions when they are administered. Drugs are chemicals, and the human body operates by a vast series of chemical reactions.
TOXIC EFFECTS OF DRUGS
Are undesired effects that may be unpleasant or even dangerous.
Adverse Effect
Development of adverse reaction from
simple overdose which can be caused
by individual response to the drug, high
or low body weight, age or underlying
pathology that alters the effects of the
drug
Primary Action
Effects of the drug in addition to the
desired pharmacological effect
Secondary Action
Excessively responsive to either the
primary or the secondary effects of a
drug. It may result from pathological
or underlying condition
Hypersensitivity
Occurs when the body forms antibodies to a particular drug,
causing an immune response when the person is re exposed to
the drug
Drug Allergy
Four Classification of Drug Allergy: ACSD
- Anaphylactic
reactions - Cytotoxic reactions
- Serum sickness
- Delayed reactions
Drug induced tissue and organ damage:
- Dermatologic Reaction
- Superinfections
- Blood Dyscrasia
- Toxicity
5 Alteration in Glucose Metabolism - Electrolyte Imbalances
- Sensory Effect
- Neurological Effect
Drugs that affect the developing fetus or
embryo which may cause death or congenital
defects
Teratogenicity
