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Pharmacology

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Major Subdivisions Pharmacokinetics How the body responds to a drug: absorption, biotransformation, metabolism, ... – PowerPoint PPT presentation

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Title: Pharmacology


1
Pharmacology
  • Composition, uses, effects
  • Primary Effect desired or intended
  • Secondary Effect unintended
  • Placebo effect
  • Any substance that in small amounts produces
    significant changes in a persons body

2
Major Subdivisions
  • Pharmacokinetics How the body responds to a
    drug absorption, biotransformation, metabolism,
    etc.
  • Routes of Administration
  • Oral
  • Parenteral
  • Intravenous
  • Subcutaneous
  • Intramuscular
  • Inhalation
  • Absorption
  • Transdermal

3
Biotransformation
  • When substance enters the bloodstream via oral
    ingestion, the liver kidneys becomes directly
    involved, thereby reducing the effects of the
    drug (does not occur with other forms of
    administration)
  • Liver function breaks down the chemical
    compound
  • Kidney function eliminates the drug by changing
    its chemical makeup

4
Strength of the Effect
  • How quickly the concentration of the drug rises
    in the blood stream (not the dosage amount)
  • Oral administration is slow, parenteral and
    inhalation is much quicker producing a stronger
    effect
  • Water soluble
  • Fat soluble

5
Duration of the Effects
  • Halflife Amount of time the body needs to
    eliminate ½ of the substance present as measured
    by its concentration in the blood.
  • Substances are then excreted through urine,
    saliva, sweat, feces, tears

6
Subdivisions cont.
  • Pharmacodynamics examination as to what the
    drugs effects mechanism of action do to the
    body
  • Pharmacotherapeutics medical use of drugs to
    treat diseases such as chemotherapy
  • Toxicology the study of poisons

7
Distribution Elimination
  • Solubility A drugs condition of being
    dissolved in the body tissue
  • Psychoactive Drugs all are fat soluable, with
    some dissolving faster than others
  • 3 Routes of Distribution
  • Bloodstream
  • Even distribution through every individual cell
    body
  • Uneven distribution due to difference in the
    solubility factor a drugs ability to penetrate
    the cell membrane

8
Blood-Brain Barrier
  • In order for a psychoactive drug to work, what
    must happen?
  • Enter the blood stream
  • Enter the capillaries
  • Effect nerve cells
  • What is the blood-brain barrier? A selective
    resistance to the passage of some substances
    through the brains capillary walls based on
    drug soluability.

9
Blood Plasma Levels
  • There is a direct correlation between therapeutic
    and toxic responses, and a drugs concentration
    level in the blood plasma.
  • Dosing levels is often referred to in terms of
    blood plasma levels (frequency and quantity)

10
Blood Plasma Levels
  • MEC Minimum effective concentration
  • A drugs minimum concentration that must be
    present to be effective
  • Toxic Concentrations
  • Plasma levels that are too high, increasing the
    toxic effects

11
Drug Actions
  • Actions A drugs chemical interaction with some
    part of the human organism.
  • Replacing deficient chemical in the body
  • Act against bacteria
  • Disrupt cellular function

12
Pharmacological Actions
  • Use of structurally nonspecific/specific drugs
  • When a large dose of a chemical substance is
    administered and the resulting effect is a thin
    layer encompassing a group of cells
  • Examples
  • Anesthesia
  • antiseptics

13
Pharmacokinetic Process
  • Aspirin
  • Oral admin.
  • Once in the blood,
  • 80-90 binds to plasma proteins
  • 10-20 free floating
  • Free-floating aspirin exits the blood exerts
    therapeutic effects
  • Metab. Begins in the blood is converted to
    salicylic acid, continues in the liver
  • Excreted in the kidneys

14
Pharmacokinetic Process
  • Tylenol
  • Oral
  • Absorbed in upper gastrointestinal
  • In blood, 20-50 binds to plasma proteins, 50-80
    is free-floating
  • Free-floating acetaminophen. Exits the blood
    exerts therapeutic effects
  • Metabolized in the liver
  • Excreted via the kidneys

15
Drug-Receptor Interaction
  • How the drug molecule interacts (bonds) with the
    appropriate receptor will produce a
    greater/lesser effect

16
Effects on Cell Function
  • Activation increase the cell rate by an agonist
    drug
  • Cocaine on the CNS
  • Inactivation decrease the rate of cellular
    function by an antagonist drug
  • Narcotics
  • Alcohol
  • Sedatives

17
Inactivation
  • Blocking prevention or obstruction of a
    particular response (antihistamines)
  • Inhibition effects the normal activities of
    brain production of certain chemical (LSD)
  • Substitutive replacement of a critical
    substance not being produced (estrogen)
  • Curative destruction or prevention of growth of
    disease causing organisms
  • Irritation abnormal stimulation of a body
    part/function (laxatives)

18
Influences on Drug Actions
  • Age
  • Body Weight
  • Gender
  • Time
  • Disease
  • Mind-Set
  • Environmental Setting

19
Dose-Response Relationship
  • Dose amount or quantity of a drug taken at a
    given interval
  • Threshold dose the minimum to get an effect
  • Subthreshold dose it doesnt work
  • Maximal Efficacy dose at which a response
    occurs, and continues to increase in magnitude
    before reaching a plateau or threshold. Once the
    threshold is reached, the response cannot be
    increased even if more of the drug is introduced
  • 10 is better than 2

20
Drug Effects
  • Maximum Effect greatest response irregardless
    of the amount administered
  • Median Median effective dose how much is
    required to have an effect on 50 of the subjects
  • Therapeutic Range the level of medication
    administered that creates a response between the
    minimum dose effect and the maximum safe
    concentration of the drug
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