1. Basic Pharmacology
Chapter 6

2. Pharmacology Study of drugs and their actions on living organisms
Drug Names:
Drugs have different names, many have similar spelling.
Exact names and spelling are imperative

3. Drug Names Chemical Name: Generic Name: Official Name: Trademark:
Exact chemical structure of a drug
Ex. 4-Thia-1-azabicyclo[3.2.0]heptane 2-carboxylic acid, 6-[(aminophenylacetyl)amino]-3,3-dimethyl-7-oxo-,[2S-[2α,-5 α,6β(S*)]]-
Generic Name:
Drugs common name
Ex. Ampicillin
Official Name:
Name under which the drug is listed by the FDA
Ex. Ampicillin, USP
Trademark:
Brand or Trade name
Only the manufacture who owns the drug can use the brand/trade name
Ex. Principen, Polycillin

4. Drug Classifications Drugs are classified by: Body System
Which body system the affect?
Therapeutic use or clinical indications
What disease or illness is being treated?
Physiological or chemical action
What does the drug do in the body?
Prescription or non-prescription
Does the medication require a prescription or can it be purchased OTC?
Illegal Drugs
Is the drug used for non-therapeutic reasons?

5. Basic Principles Drugs act in the human body in the following ways:
Drugs change a physiological activity within the body
They do no create new responses
Ex. Blood Pressure Medication
Drug forms a chemical bond within specific sites (receptors) within the body
Relationship between drug and receptor is like a key

6. Basic Principles (continued)
Agonist:
Drugs that interact with a receptor to cause a response
Antagonist:
Drugs that attach to a receptor but do not cause a response
Partial Agonist:
Drugs that interact with a receptor to cause a response but prevent other responses

7. 4 Stages All drugs go through 4 Stages: Absorption Distribution
Metabolism
Excretion

8. Absorption
Process by which a drug is transferred from its site of the body entry to circulating body fluids (blood, lymph) for distribution
Rate of absorption depends upon:
Route of administration
Blood flow through the tissue where drug administered
How well the drug can dissolve (solubility)
Proper reconstitution and dilution of drugs
Administration into the correct tissue

9. Absorption (continued)
Routes of Administration:
Enteral:
Drugs administered directly into the GI tract
Ex. Orally
Parenteral:
Drugs administered that bypass the GI tract
Ex. Injections
Subcutaneous
Beneath the skin
Intramuscular:
Within a muscle
Intravenous:
Within a vein
Percutaneous:
Drugs administered through the skin or a mucous membrane
Ex. Inhalation, sublingual and topical

10. Absorption (continued)
Absorption of drugs applied to the skin (topical) in influence by:
Amount and strength of drug
Length of contact time
Size of the affected area
Thickness of the skin surface
Tissue hydration
Skin condition—intact or non-intact

11. Distribution
The ways drugs are transported by circulating body fluids to the sites of action (receptors) and to the site of metabolism & excretion
Organs with the greatest blood supply (heart, liver, kidneys & brain) receive the drug most rapidly
Tissues with lesser blood supply (muscle, skin, fat) receive the drug move slowly
Once absorbed, a drugs distribution rate is determined by:
Chemical properties
How the drug is affected by the blood and tissues it contacts

12. Metabolism Process by which the body in-activates drugs
Liver is the primary site for drug metabolism
Other tissues & organs that metabolize drugs:
White Blood Cells
GI Tract
Lungs
Other factors that help to regulate drug metabolism
Genetics
Environment
Physiology
Other drugs
Illnesses
Age

13. Excretion Elimination of a drug from the body
Urine and feces are the primary routes
Other routes of elimination include:
Evaporation from skin
Exhalation from lungs
Secretion into saliva & breast milk

14. Drug Action No drug has a single action
When a drug is absorbed & distributed, the desired action (expected response) usually occurs
All drugs can affect more than one body system, therefore potentially causing side effects and adverse drug reactions
Side Effects:
Unintended reactions to a drug given in a normal dose
Drug Reaction:
Unintended effect on the body from using a legal drug, illegal drug or 2 or more drugs
Each drug has parameters—therapeutic actions to expect, side effects to expect, adverse drug reactions to report and probable drug interactions.
Dosages are adjusted and monitored for the nest therapeutic effect

15. Allergic Reactions
Unfavorable response to a substance that causes a hyper-sensitivity reaction.
Occur in persons previously exposed to a drug
Person develops antibodies to the drug, on re-exposure the antibodies cause a reaction
Most common reaction:
Urticaria (Hives)
Anaphylaxis
Severe, life threatening sensitivity to an antigen
Sweating, shortness of breath, low blood pressure, irregular pulse, respiratory congestion, swelling of the larynx, hoarseness, dyspnea

16. Reactions Mild Reactions Anaphylaxic Reaction:
Warning to not take medication again
Anaphylaxic Reaction:
Never use the drug again
Receive information about the drug
Tell health professional about the reaction
Wear a medical alert bracelet

17. Factors Influencing Drug Action
Some people react differently to same drug at the same dosages
Factors that affect a person’s response to a drug:
Age
Body Weight
Metabolic Rate
Illness
Willingness to take drugs
Placebo effect
Tolerance
Dependence
Cumulative Effect

18. Drug Interactions
Drug interaction occurs when the action of one drug is altered by the action of another drug
Occurs in 2 ways:
Drugs, when combined, INCREASE the actions of one or both drugs
Drugs, when combined, DECREASE the effectiveness of on or both drugs

19. Drug Information
With thousands of drugs it is impossible to memorize information about all of them
Be familiar with resources:
American Hospital Formulary Service Drug Information
Drug Interaction Facts
Drug Facts and Comparison
Handbook of Nonprescription Drugs
Natural Medications Comprehensive Database
Physicians Desk Reference (PDR)
Package Inserts