Study of the history, sources, and physical and chemical properties of drugs
Also looks at the ways in which drugs affect living systems
Various subdivisions of pharmacology have evolved
Study of the biochemical and physiological effects of drugs
Study of drugs’ mechanisms of action
Study of the absorption, distribution, biotransformation (metabolism), and excretion of drugs
Four steps Absorption Distribution Metabolism Excretion
Study of how drugs may best be used in the treatment of illnesses
Study of which drug would be most appropriate or least appropriate to use for a specific disease; what dose would be required; etc.
The study of drugs derived from herbal and other natural (plant and animal) drug sources
Studying compositions of natural substances helps to gain knowledge for developing synthetic versions
Study of poisons and poisonings All drugs have the potential to become toxic.
Ancient Egypt: the cradle of pharmacology These medical sources listed over 700 different
remedies for different ailments. First century: Dioscorides prepared De Materia
Medica: Listed and classified 600 different plants used for
medicinal purposes; first time plants were ever classified
Drugs derived from: Natural sources Semisynthetic sources Synthetic sources
Symptomatic treatment Prevention Diagnostic drugs Curative Health maintenance Contraception
Tablets Timed or sustained release Tablets or controlled release Capsule Troches Suppositories
Solutions Douche Suspensions Emulsions Topicals
Patches Drug implants
Ampules Sterile Sealed glass or plastic container Contain a single liquid dose
Vials: either single or multiple dose Glass or plastic container Sterile liquid dose Sealed with a rubber diaphragm
Chemical name The drug’s chemical composition and molecular
structure Generic name (nonproprietary name)
Name given by the United States Adopted Names Council
Allows the drug to be marketed
Chemical name (+/-)-2-(p-isobutylphenyl) propionic acid
Generic name Ibuprofen
Trade name Motrin
Also called trade name (proprietary name) The drug has a registered trademark; use
of the name is restricted by the drug’s owner (usually the manufacturer)
Allows the drug to be commercially distributed The superscript ® is registered by the U.S. Patent
Office and approved by the FDA (Food and Drug Administration)
Pure Food and Drug Act of 1906 Required all drugs to meet minimal standards
Federal Food, Drug, and Cosmetic Act of 1938 Required the drug to be safe before being
distributed over state lines
(continues)
1970: Comprehensive Drug Abuse Prevention and Control Act Also known as Controlled Substance Act:
classified drugs according to their abuse potential
Regulates the manufacture and distribution of drugs causing dependence
CONTROLLED SUBSTANCES SCHEDULES
Schedule I High potential for abuse
No medical use HeroinLSD
Schedule II High potential for abuse
Accepted medical use
MorphineDemerol
Schedule III Lower potential for abuse
Accepted medical use
Librium, Valium, hydrocodone, Tylenol with codeine
Schedule IV Lower potential for abuse
Accepted medical use
LibriumValium
Schedule V Lowest potential for abuse
Accepted medical use
LomotilRobitussin A-C
Prescription drugs = legend drugs Drugs prescribed by:
Physician Nurse practitioner Physician’s assistant Dentist Veterinarian Others
Drugs Alter existing cellular or chemical functions Exert their action by forming a chemical bond
with specific receptors within the body Referred to as a lock and key effect
Drug receptor interaction. Binding with specific receptors occurs only when the drug and its receptors have a compatible chemical
shape.
Receptors The better the fit, the stronger the drug’s
affinity, thus Drug effect occurs at lower doses
Agonist effect Antagonistic effect Adverse drug effect Therapeutic effect
Routes Oral Parenteral Topical
The metabolism of a drug and its passage from the liver into the circulation Metabolism occurs in the liver
Liver enzymes react with the drug Increases the dosage requirement
The same drug—given IV—bypasses the liver, preventing the first-pass effect from taking place, and more drug reaches the circulation.
The transport of a drug in the body by the bloodstream to its site of action
The elimination of drugs from the body Kidneys (main organ) Liver Bowel
Renal excretion of drugs. Note sites where drugs are secreted and
reabsorbed.
Half-life The time it takes for one half of the original
amount of a drug to be removed from the body