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

C ONTROLLED S UBSTANCES S CHEDULES Schedule IHigh potential for abuse No medical useHeroin LSD Schedule IIHigh potential for abuse Accepted medical use Morphine Demerol Schedule IIILower potential for abuse Accepted medical use Librium, Valium, hydrocodone, Tylenol with codeine Schedule IVLower potential for abuse Accepted medical use Librium Valium Schedule VLowest potential for abuse Accepted medical use Lomotil Robitussin 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