CHAPTER © 2011 The McGraw-Hill Companies, Inc. All rights reserved. 50 Principles of Pharmacology

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Learning Outcomes 50.1Describe the five categories of pharmacology. 50.2Differentiate between chemical, generic, and trade names for drugs. 50.3Describe the major drug categories. 50.4Identify the main sources of drug information.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Learning Outcomes (cont.) 50.5Distinguish between over-the-counter and prescription drugs. 50.6Compare the five schedules of controlled substances. 50.7Describe how to register or renew a physician with the Drug Enforcement Administration (DEA) for permission to administer, dispense, and prescribe controlled drugs.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Learning Outcomes (cont.) 50.8Carry out the procedure for renewing medications using a telephone. 50.9Describe how vaccines work in the immune system Organize patient education topics related to the use of nonprescription and prescription drugs.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Introduction Pharmacology – science or study of drugs Medication errors can result in injury or death Medical assistant –Knowledge of the foundations of pharmacology –Understand role of drugs in ambulatory medical facilities

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Medical Assistant’s Role in Pharmacology Prescription drugs – physician’s order required to dispense and administer OTC drugs – purchased by patient for self-treatment You should –Be sure the physician is aware of all medications the patient is taking –Ask patients about use of alcohol and recreational drugs –Provide patient education

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Medical Assistant’s Role in Pharmacology (cont.) Administration of drugs –Check state regulations scope of practice –Understand pharmacologic principles –Translate prescriptions –Answer basic patient questions –Adhere to legal requirements –Keep accurate records

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Drugs and Pharmacology Drug – chemical compound used to prevent, diagnose, or treat disease Pharmacognosy – study of characteristics of natural drugs and their sources Pharmacodynamics – study of what drugs do to the body

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Drugs and Pharmacology (cont.) Pharmacokinetics – study of what the body does to drugs Pharmacotherapeutics – study of how drugs are used to treat disease Toxicology – study of poisons or poisonous effects of drugs

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Drugs and Pharmacology (cont.) Prescribe – physician gives a patient a prescription to be filled by a pharmacist Administer – give a drug by injection, mouth, or other route that introduces it into the body Dispense – health-care professional distributes the drug, in a properly labeled container, to the patient for whom it is prescribed

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Sources of Drugs Natural products –Plants –Animals –Minerals –Bacteria and fungi Chemical development of natural products –Synthesis of chemical makeup of a drug –Manipulation of genetic information Foxglove – source of digitoxin

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge 1. What is the role of the medical assistant in pharmacology? ANSWER: The medical assistant should be sure the physician is aware of all medications the patient is taking, including OTC medications; ask patients about use of alcohol and recreational drugs; and provide patient education. If the scope of practice permits, the medical assistant may also be responsible for administering some medications.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge 2. Matching: ___ Study of poisons A.Pharmacokinetics ___ Study of what the body does to drugsB.Pharmacognosy ___ Used to prevent, diagnose, or treat diseaseC.Toxicology ___ Study of what drugs do to the bodyD.Pharmacotherapeutics ___ Study of how drugs are used to treat diseaseE.Pharmacodynamics ___ Study of characteristics of natural drugF.Drugs and their sources ANSWER: F E D C B A

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Pharmacodynamics Mechanism of action of a drug to produce a therapeutic effect Interaction between drug and target cells and body’s response to the interaction

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Pharmacokinetics What the body does to a drug –Absorption Conversion of a drug into a form the body can use Allows the drug to enter the blood and tissues Rate and extent of absorption depend on –Route of administration –Characteristics of the drug –Distribution Transportation of a drug from site of administration to site of action

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Pharmacokinetics (cont.) –Metabolism Drug molecules are transformed into metabolites Usually in liver, some in kidneys Affected by age, genetic makeup, and characteristics of drug –Excretion Manner in which a drug is eliminated from the body Most via urine

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge What is the difference between pharmacodynamics and pharmacokinetics? ANSWER: Pharmacodynamics is the way a drug affects the body to produce its effect. It is the interaction between the drug and cells and the body's response to the interaction. Pharmacokinetics is what the body does to the drug and includes absorption, distribution, metabolism, and excretion of the drug. Very Good!

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Pharmacotherapeutics Clinical pharmacology Drug names –Generic – official name –International nonproprietary name –Chemical name –Trade – brand or proprietary name Generic and trade names used most often

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Pharmacotherapeutics (cont.) Drug categories –Action on the body –General therapeutic effect –Body system affected Indication and labeling –Indication – reason(s) for using a drug –Must be approved by FDA to be part of labeling –Off-label use

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Pharmacotherapeutics (cont.) Safety –Adverse reaction to drug –Interaction with another medication –Be alert to patient complaints after starting a new drug Efficacy – drug is working as expected

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Pharmacotherapeutics (cont.) If a patient complains a drug is not working –The patient may not understand how the drug works –Dosage may need to be adjusted –Therapeutic level may not have been reached –Wrong drug may have been prescribed –Some drugs work better for one patient than another –Some forms of drugs work better

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Kinds of Drug Therapy Acute – improve a life- threatening or serious condition Empiric – given before test results are available Maintenance – maintain health Palliative – reduce severity of a condition or pain Prophylactic – prevent disease Replacement – provide chemicals a patient lacks Supportive – for a condition other than the primary disease Supplemental – avoid a deficiency

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Toxicology Study of poisonous effects of drugs –Adverse effects –Drug interactions Patient education –Inform physician of any adverse effects –Discuss concerns with physician or pharmacist

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge 1.Mr. Anderson is complaining that the new medication does not seem to be working. What may be the reason for this? ANSWER: Mr. Anderson may not understand how the drug works. His dosage may need to be adjusted, or the therapeutic level may not have been reached. The wrong drug may have been prescribed for him, or this particular drug may not work for as well for him as for another patient. He may need the medication in a different form.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge 2.Toxicology includes which of these? A.Poisons and poisonous effects of drugs B.Excretion of drugs C.Adverse effects of drugs D.Drug interactions E.Metabolism of drugs ANSWER:

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Sources of Drug Information Sources must be up-to-date PDR –Information provided by pharmaceutical companies –Information closely resembles package insert –Published annually Drug Evaluations – published annually by the AMA

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Sources of Drug Information USP/NF –Official source of drug standards –Published about every 5 years AHFS – published by the American Society of Hospital Pharmacists

© 2011 The McGraw-Hill Companies, Inc. All rights reserved The FDA Regulatory Function New drugs –Clinical trials Safety Efficacy Drug manufacturing –Identity –Strength –Purity –Quality OTC drugs Prescription drugs Pregnancy categories –A–A –B–B –C–C –D–D –X–X

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Controlled Substances Drugs categorized as potentially dangerous and addictive Strictly regulated by federal laws Comprehensive Drug Abuse Prevention and Control Act (1970) –Created the DEA –Strengthened drug enforcement authority –Schedules – based on abuse potential

© 2011 The McGraw-Hill Companies, Inc. All rights reserved ScheduleAbuse PotentialExample IHighHeroin IIHighMorphine IIILower than II (moderate dependence) Butabarbital IVLower than III (limited dependence) Diazepam VLower than IV (very limited dependence) Antidiarrheals Controlled Substances (cont.)

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Controlled Substances (cont.) Comprehensive Drug Abuse Prevention and Control Act (1970) –Controlled substance labeling –Doctor registration –Ordering controlled substances –Drug security –Record keeping –Dispensing records –Inventory records –Disposal of drugs

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Writing Prescriptions Parts of a prescription –Superscription Patient information –Inscription Name of the drug Amount of drug per dose –Subscription – directions to the pharmacist –Signature – patient instructions

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Writing Prescriptions (cont.) Prescription for a single medication

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Writing Prescriptions (cont.) Prescription for multiple medications

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Writing Prescriptions (cont.) Keep prescription blanks secure Telephone prescriptions –Only at request of the physician –Follow facility policy –Document carefully

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge Which of the following sources of drug information is most like the package insert? A. AHFS B. PDR C. USP/NF D. Drug Evaluations ANSWER: Match ___ Contains the patient informationA. Subscription ___ Name of the drug and dosageB. Signature ___ Instructions to the pharmacistC. Superscription ___ Patient instructionsD. Inscription C D B A ANSWER: Correct!

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Vaccines Special preparations made from microorganisms Administered to produce reduced sensitivity to or increased immunity to an infectious disease Body creates antibodies in response to an antigen (vaccine)

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Antibody Formation 1.Antigen enters body 2.White cells produce antibodies 3.Antibodies combine with antigens to neutralize them 4.This arrests or prevents reaction or disease 5.Vaccines stimulate antibody formation and reduce symptoms if patient is exposed to disease

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Immunizations Schedule for immunizations for children up to age 16 years Pre-exposure immunizations Post-exposure immunizations – antiserum or antitoxin that contains antibodies

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Immunizations (cont.) Medical assistant should be familiar with –Indications –Contraindications –Dosages –Administration routes –Potential adverse effects –Methods of storing and handling

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge ANSWER: Vaccines are administered to a person to produce reduced sensitivity to or increase immunity to an infectious disease. Why are vaccines given to patients?

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Patient Instruction on Medications Medical assistant role is important OTC drugs –Should not be used to avoid medical care –May not produce enough therapeutic benefit –May be dangerous in combination with other substances or drugs –May mask symptoms or aggravate a problem

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Patient Instruction on Medications (cont.) Prescription drugs –Inform patient about special considerations and drug safety precautions –Encourage patient to Maintain a complete list of medications Report adverse reactions Patient compliance

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Patient Instruction on Medications (cont.) To prevent medication errors, be sure patient understands prescription –How and when to take the medication –Appropriate language –Demonstrate if necessary –Review warnings about the medication

© 2011 The McGraw-Hill Companies, Inc. All rights reserved Apply Your Knowledge Mrs. Del Rosario tells you she does not take any medication when you are taking her history. When you question her further, she says she takes an OTC pain medication occasionally and routinely take several herbal supplements. What should you tell her? ANSWER: You should tell her it is important to report all medications, including OTC drugs and herbal and other supplements, to the physician and that they may be dangerous in combination with other substances or drugs or may mask symptoms or aggravate a problem. Nice Job!

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary 50.1The five categories of pharmacology include pharmacognosy, pharmacokinetics, pharmacodynamics, pharmacotherapeutics, and toxicology. 50.2The chemical name of a drug is based upon the chemical makeup of the medication. The generic name is the drug’s official name, and the trade name is the name given a medication by the manufacturer. A medical assistant should be familiar with both the generic and trade names.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 50.3Drug categories are sometimes named based upon their action; for example, anticonvulsants are used to treat convulsions (seizures). The major drug categories and their actions are outlined in Table The main book sources for drug information are the Physicians’ Desk Reference (PDR), Drug Evaluations, United States Pharmacopeia/National Formulary, and the American Hospital Formulary Service. You may also access medication information from package inserts, at the web site or at other reliable Internet sites.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 50.5Nonprescription or over-the-counter drugs can be obtained without a physician’s order. For prescription drugs, patients must have a physician’s order. 50.6For drugs that have been classified as controlled substances because they are potentially dangerous and addictive, extensive regulations apply. There are five schedules (I to V) of controlled substances, with schedule I being the most addictive.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 50.7All physicians must be registered with the Drug Enforcement Administration and follow the legal requirements of the Controlled Substances Act of 1970 to administer, dispense, and prescribe controlled drugs. The medical assistant must follow these legal requirements when registering the physician. 50.8Receiving and telephoning medication refills is frequently done by the medical assistant for all medications except schedule II and III drugs.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved In Summary (cont.) 50.9Immunizations usually contain killed or weakened organisms. When given, they stimulate the body to build up a resistance to the organism. They are used to provide immunity against specific diseases Patients should be educated about why, when, and how they should take medications. This includes instruction to ensure patient compliance regarding nonprescription and prescription drugs, herbal remedies, and supplements. Patients should also be instructed about the dangers of medication combinations, the importance of reporting an adverse effect, and maintaining a complete medication list.

© 2011 The McGraw-Hill Companies, Inc. All rights reserved End of Chapter 50 It is easy to get a thousand prescriptions but hard to get one single remedy. ~Chinese Proverb