Intro to Pharmacology

What is Pharmacology? The science of pharmacology involves the action of drugs on humans and animals. The aim of drug therapy is to diagnose, treat, cure, or lessen the symptoms of disease. The study of pharmacology applies properties and knowledge of drugs, mechanism of drug action, anatomy and physiology, and pathology,

Key Areas and Terms in Pharmacology Pharmacodynamics – study of the action of drugs on living tissue Pharmacokinetics – study of the process of drug absorption, distribution, metabolism, and excretion Pharmacotherapeutics – study of the use of drugs in the treatment of disease Pharmacy – science of preparing and dispensing medication Posology – study of the amount of drug required to produce therapeutic effects Toxicology – study of the harmful effects of drugs on living tissue

What is a drug? A drug is any substance that can cause a change in function when administered in a living organism.

Therapeutic Effect Side Effect Adverse Effects Toxic Effects Intended Effect Not necessarily harmful - May be harmful With prolonged use, may effect function of vital organs Reduction in dosage or switching can minimize harmful consequences All drugs will act as a poison when taken in excess Can be life threatening Drug must be stopped

N-Methyl-3-phenyl-propylamine Drug Nomenclature All drugs are identified by a generic name, a chemical name, and a proprietary (brand) name. The official name of the drug is the generic name. Usually a contraction of the chemical name. The chemical name describes the molecular structure of the drug. The proprietary (brand/trade) name is assigned by the drug manufacturer. Prozac Fluoxetine HCl N-Methyl-3-phenyl-propylamine

A drug can have many brand names as there are manufacturers producing it! Ex. Naproxen Sodium (generic name) Trade Names: Naprelan, Aleve, Naprosyn, Anaprox

Examples of Generic, Chemical, and Brand Names Generic Name Chemical Name Brand Name Fluoxetine HCl N-methyl-3-phenyl-propylamine Prozac Acetaminophen 4-Hydroxyacetanilide Tylenol Ibuprofen 2-p-Isobutylphenyl-propionic acid Motrin

Comparison Between Brand Name Drugs and Generic Drugs The inventor of a new drug may apply for patent protection. If awarded, the manufacturer is given up to 20 years exclusive rights to manufacture and distribute the new drug. Once the drug is off the patent, other drug companies may manufacture a generic equivalent. Generic drugs contain the same active ingredients as the original manufacturer’s drug, in the same strength. However, generic drugs may contain different inactive ingredients, which may affect how much of the drug is available to the body.

Drug Safety Food and Drug Administration (FDA) has established guidelines that govern the approval of drugs. Before approval, each drug must fulfill two requirements: Efficacy – proof of its effectiveness Safety – Specific criteria as determined by extensive animal testing and controlled human testing

Routes of Administration

Routes of Administration Appropriate administration route depends on: The available dosage form of the drug The patient’s age The patient’s condition (LOC, etc.)

Oral (PO) Most convenient and most commonly used route of administration Advantages:. Examples: Tablets, capsules, liquids Infants can be given drugs in liquid form Unconscious patients can receive meds with NG tube Disadvantages: Some cannot be given orally as they become inactivated by stomach acid Some can combine chemically with certain foods or beverages to produce adverse side effects (tetracycline and dairy)

Parenternal Any route of administration other than the oral route Intradermal Subcutaneous Intramuscular Intravenous Sublingual Rectal Vaginal Topical Transdermal Inhalation

Subcutaneous Injection of a liquid into the fatty layer of tissue just below the dermis of the skin but above the muscle layer Slower absorption of the drug because of fewer blood vessels in the layer (Insulin, Heparin, Allergy shots) Common abbreviations (s.q., SQ, subQ, S.C.)

Intramuscular Injection of liquid into the belly of a large muscle More rapid absorption than subcutaneous Only 5 injection sites that allow for administration with lowest risk of damage to adjacent nerves and vessels Deltoid Vastus Lateralis Rector Femoris Ventrogluteal Dorsogluteal

Intravenous Injection of drug directly into the vein Effect can be seen immediately Drug does not need to be absorbed Examples: Valium for control of continual seizures Chemotherapy drugs for cancer treatment Pentothal for induction of general anesthesia

Sublingual Drug, usually in tablet form, is placed under the tongue and allowed to dissolve slowly NOT swallowed Faster therapeutic effect than the oral route Example: Nitroglycerin tablets and spray for angina

Rectal Reserved for certain clinical situations, such as a vomiting patient and medication not available in injectable form Preferred route when drugs are administered to relieve constipation or hemorrhoids Absorption is slow and often unpredictable in effectiveness

Topical Applied directly to the skin or the mucous membranes of the eye, ear, nose, or mouth Effect usually local, not systemic Examples: Bacitracin Antibiotic Timoptic Eye drops

Transdermal Applied to the skin via physical delivery through a porous membrane Effects felt systemically Release of drug over time, providing sustained therapeutic blood levels Example: Nitroglycerin transdermal patch

Inhalation Administration involves inhaling of a drug in gas or liquid form Absorbed through the alveoli of the lunges Example: Albuterol for Asthma (Bronchodialator)