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