Introduction to Pharmacology PHARM TECH

Pharmacology  Pharmacology is the science that deals with the study of therapeutic (beneficial) agents.  Knowledge of the properties of therapeutic agents is vital in providing quality health care.  It is an ever changing, growing body of information that continually demands greater amounts of time and education from health care workers.

What you will learn:  Definition of pharmacology and its major subdivisions  Define a drug  Explain the differences between therapeutic effect, side effect, and toxic effect  Identify a drug receptor  Trace the interactions between agonists and antagonists with the receptors  Explain the relationship between drug dosage, drug response, and time  Explain drug safety and therapeutic index  Describe three names by which drugs are known  List two common drug reference books

Doctors and Pharmacists How do physicians and pharmacists keep track of the medicine that exists from year to year?  Physicians’ Desk Reference (PDR)-reference most widely used by physicians, pharmacists, and nurses.  Updated yearly  Provides information on indications for use, dosage and administration, contraindications, and adverse reactions

Terms Used 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

Drug  General definition -- any substance that can cause a change in function when administered to a living organism  Pharmacologically -- any medication that is used in treating a disease or disorder.  Drug sources -- natural sources, plants, etc.

Drug Effects  Therapeutic effect – intended effect.  Side effects – are not necessarily harmful. They may have undesired effects.  Adverse effects-may be harmful. With prolonged use may effect function of vital organs, e.g., liver and kidneys. Reduction of dosage or switching to other drug may minimize harmful consequences  Toxic effects – all drugs will act as poison when taken in excess (drug poisoning). Effects are extremely harmful and sometimes even life threatening. The drug must be stopped and occasionally supportive treatment and administration of antidotes (remedy) may be required.

Terms Appropriate to Any Drug  Site of action – is unknown for some drugs but determined for most  Mechanism of Action – how the drug produces its effects  Lower receptor site – specific location on certain cells; similar to a lock and key concept  Agonists and antagonists-the chemical substances can alter a drug’s action either by facilitating (helping) or interfering with such as delaying or obstructing its use.  Dose -the exact amount of a drug administered in order to produce a specific effect. ie. 1000mg of Acetaminophen for pain relief  Potency – a measure of strength or concentration of a drug to produce a specific effect. ie. Benadryl Liquid 12.5mg/5ml

Response Time of a Drug  Response -the effect of the drug on the site of action. 3 ways to label the response: 1. response proportional (compared) to amount of drug given 2. maximal response achieved also known as the ceiling effect 3. Dose response that is above the ceiling effect. These are likely to produce toxic effects (overdose).  ED50-A dose that produces ½ the maximal response, referred to as (effective dose 50)  Onset of action – the time from drug administration to the first observable effect. The response will continue as long as effective concentration of drug remains at site of action.

Drug References 1. Pharmacopoeia/National Formulary (USP/NF)  The official drug list recognized by U.S. government  Provides information concerning physical and chemical properties of drugs  Revised every 5 years  Used primarily by drug manufacturers to ensure drug production according to government standards.

Drug References 3. Physicians’ Desk Reference (PDR)-See slide 4  Reference most widely used by physicians, pharmacists, and nurses. 4. Drugs Facts and Comparisons  available in bound format and, most frequently used, loose leaf form  index and drug information service subscribed to by most medical libraries  updated monthly  provides most current drug information on a regular basis

Drug References 5. United Sates Pharmacopoeia Dispensing Information (USP DI)  United States Pharmacopoeia Convention, Inc. publishes series of volumes under general title  updated yearly  Volume I: Drug Information for the Health Care Professional -- provides in-depth information about prescription and OTC medications and nutritional supplements  Volume II: Advice for the Patient -- provides drug information for the patient, e.g., how to take, signs to watch out for, etc.

Drug References 6. Drug Monograph (profile or an insert)  An instrument that provides information prescription, over-the- counter (OTC), investigational, nutritional and herbal products.  Provides the important data about the drug.  All manufacturers’ monographs provide essentially the same items of information about each drug: description action indications usage in pregnancy adverse reactions dosages (and administration) packaging availability