1. Drugs and Medicines
Version 1.01 1

2. Orgins of Pharmacology
From earliest times people have used natural substances such as medicinal herbs to
-- relieve pain
-- heal injuries
-- cure diseases
Some folk remedies contained certain active ingredients that were of medicinal value. 2

3. Examples of Folk Remedies
Morphine
extracted from poppy used to treat pain in the 19th century
Salicyclic acid
extracted from willow bark as a precursor to aspirin.
Quinine
Used in South America to treat malaria 3

4. Definition of a Medicine
Any chemical substance that
Alters a physiological state
Alters mood or emotions
Alters incoming sensory sensations
Sometimes it is difficult to determine whether a drug has any medicinal value.
The legitimate purpose of a drug is usually to improve health.
Use of drugs in some cases is controversial. 4

5. The Placebo Effect
Healing is a complex interaction betwe en mind and body that is not entirely understood
The Placebo Effect
Merely taking any medicine may trigger responses in the body that result in changes in the mental/emotional or physiological states of the person without having any medicinal action. 5

6. Drugs and medicines
Access to drugs and medicines is controlled in most countries but the definition of what constitutes a drug may vary
Examples
Melatonin
Codeine 6

7. Methods of Administering Drugs
Drugs must reach blood stream to be transported to critical tissues.
The method of administration determines rate at which the drug is absorbed in the blood.
Five common points of entry:
Oral
Inhalation
Topical
Injection
Anal 7

8. Methods of Administering Drugs
Injection methods
Subcutaneous
Intramuscular
Intraveneous 8

9. Research, Development and Drug Testing
Development of new drugs is long and expensive process
Several stages in development include:
Isolation or chemical synthesis
Laboratory studies
Animal testing
Clinical testing
Approval by the FDA for market 9

10. Research, Development and Drug Testing
The development of a new drug is a time consuming process
Determination of the Lethal Dose or LD50. This is the concentration that will kill 50% of the animals in a test sample
The Effective Dose or ED50. is the concentration necessary to bring about a noticeable effect in 50% of the test sample
The Therapeutic Index is the ratio of
LD50.
ED50. 10

11. Clinical Trials
All drugs that are approved for market must be clinically tested multiple times
Most clinical tests are done on volunteers using a double blind.
Neither the researcher know in advance who is receiving the therapeutic medicine and who is receiving a placebo 11

12. Drug Development
All medicines have some side effects and the appropriate dosage must be determined,
To determine the following must be considered
Lethal Dose or LD50
Effective Dose or ED50
Therapeutic Index
Toxic Range
Theraputic Level
Subtheraputic level 12

13. Contraindications or Side Effects
Contraindications are additional and often undesirable effects that result from the use of a particular drug to treat a particular condition.
Side effects are somewhat relative depending on the reason the drug is prescribed 13

14. Risk to Benefit Ratio
The prescribing physician must weigh the benefits from the use of a drug against the undesirable side effects when determining a suitable level of risk
The level of risk that is acceptable is related to the severity and the degree to which the condition is life threatening
Examples: Chemotherapy, Pain Killers etc 14

15. Tolerance Over time the body adapts the presence of a drug
The person receiving the drug needs ever larger doses to achieve the original effect
Increased risks of dependency/addiction
Increased risks of toxic levels
Possibility of immunity in anti-bacterials. 15

16. Thalidomide --An Example of Improper Drug Approval
Developed in Germany in the 1953
Used as a tranquilizer ( )
Prescribed to combat morning sickness in the early months of pregnancy
Marketed widely in Europe but never approved by the FDA in the USA
Caused major birth defects in ABOUT 10,000 children whose mothers had taken thalidomide. 16

17. Thalidomide
Has two optical isomers, one of which is a powerful teratogen.
Used to treat some symptoms of Hansen’s disease (Leprosy)
Chiral
Carbon 17

18. Drug Classification Drug Categories Depressants Stimulants Antacids
Analgesics
Antibacterial
Antiviral
Mind Altering Drugs 18