Y khoa, dược - Principles of pharmacology

50Principles of Pharmacology50-2Learning Outcomes 50.1 Describe the five categories of pharmacology.50.2 Differentiate between chemical, generic, and trade names for drugs.50.3 Describe the major drug categories.50.4 Identify the main sources of drug information.50-3Learning Outcomes (cont.)50.5 Distinguish between over-the-counter and prescription drugs.50.6 Compare the five schedules of controlled substances.50.7 Describe how to register or renew a physician with the Drug Enforcement Administration (DEA) for permission to administer, dispense, and prescribe controlled drugs.50-4Learning Outcomes (cont.)50.8 Carry out the procedure for renewing medications using a telephone.50.9 Describe how vaccines work in the immune system.50.10 Organize patient education topics related to the use of nonprescription and prescription drugs.50-5IntroductionPharmacology – science or study of drugsMedication errors can result in injury or deathMedical assistantKnowledge of the foundations of pharmacologyUnderstand role of drugs in ambulatory medical facilities50-6Medical Assistant’s Role in PharmacologyPrescription drugs – physician’s order required to dispense and administerOTC drugs – purchased by patient for self-treatmentYou shouldBe sure the physician is aware of all medications the patient is takingAsk patients about use of alcohol and recreational drugsProvide patient education50-7Medical Assistant’s Role in Pharmacology (cont.)Administration of drugsCheck state regulations scope of practiceUnderstand pharmacologic principlesTranslate prescriptionsAnswer basic patient questionsAdhere to legal requirementsKeep accurate records50-8Drugs and PharmacologyDrug – chemical compound used to prevent, diagnose, or treat diseasePharmacognosy – study of characteristics of natural drugs and their sourcesPharmacodynamics – study of what drugs do to the body50-9Drugs and Pharmacology (cont.)Pharmacokinetics – study of what the body does to drugsPharmacotherapeutics – study of how drugs are used to treat diseaseToxicology – study of poisons or poisonous effects of drugs50-10Drugs and Pharmacology (cont.)Prescribe – physician gives a patient a prescription to be filled by a pharmacistAdminister – give a drug by injection, mouth, or other route that introduces it into the bodyDispense – health-care professional distributes the drug, in a properly labeled container, to the patient for whom it is prescribed50-11Sources of DrugsNatural productsPlants AnimalsMineralsBacteria and fungi Chemical development of natural productsSynthesis of chemical makeup of a drugManipulation of genetic informationFoxglove – source of digitoxin50-12Apply Your KnowledgeWhat 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.50-13Apply Your KnowledgeMatching:___ Study of poisons A. Pharmacokinetics ___ Study of what the body does to drugs B. Pharmacognosy___ Used to prevent, diagnose, or treat disease C. Toxicology___ Study of what drugs do to the body D. Pharmacotherapeutics ___ Study of how drugs are used to treat disease E. Pharmacodynamics___ Study of characteristics of natural drug F. Drugs and their sourcesANSWER:FEDCBAImpressive!50-14PharmacodynamicsMechanism of action of a drug to produce a therapeutic effectInteraction between drug and target cells and body’s response to the interaction50-15PharmacokineticsWhat the body does to a drugAbsorption Conversion of a drug into a form the body can useAllows the drug to enter the blood and tissuesRate and extent of absorption depend onRoute of administrationCharacteristics of the drugDistributionTransportation of a drug from site of administration to site of action50-16Pharmacokinetics (cont.)MetabolismDrug molecules are transformed into metabolitesUsually in liver, some in kidneysAffected by age, genetic makeup, and characteristics of drugExcretionManner in which a drug is eliminated from the bodyMost via urine50-17Apply Your KnowledgeWhat 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!50-18PharmacotherapeuticsClinical pharmacologyDrug namesGeneric – official nameInternational nonproprietary nameChemical nameTrade – brand or proprietary nameGeneric and trade names used most often50-19Pharmacotherapeutics (cont.)Drug categoriesAction on the bodyGeneral therapeutic effectBody system affectedIndication and labelingIndication – reason(s) for using a drugMust be approved by FDA to be part of labelingOff-label use 50-20Pharmacotherapeutics (cont.)SafetyAdverse reaction to drugInteraction with another medicationBe alert to patient complaints after starting a new drugEfficacy – drug is working as expected50-21Pharmacotherapeutics (cont.)If a patient complains a drug is not workingThe patient may not understand how the drug worksDosage may need to be adjustedTherapeutic level may not have been reachedWrong drug may have been prescribedSome drugs work better for one patient than anotherSome forms of drugs work better50-22Kinds of Drug TherapyAcute – improve a life-threatening or serious conditionEmpiric – given before test results are availableMaintenance – maintain health Palliative – reduce severity of a condition or painProphylactic – prevent diseaseReplacement – provide chemicals a patient lacksSupportive – for a condition other than the primary diseaseSupplemental – avoid a deficiency50-23ToxicologyStudy of poisonous effects of drugsAdverse effects Drug interactionsPatient educationInform physician of any adverse effectsDiscuss concerns with physician or pharmacist 50-24Apply Your KnowledgeMr. 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.50-25Apply Your KnowledgeToxicology includes which of these?Poisons and poisonous effects of drugsExcretion of drugsAdverse effects of drugsDrug interactionsMetabolism of drugsANSWER:Correct !50-26Sources of Drug InformationSources must be up-to-datePDRInformation provided by pharmaceutical companiesInformation closely resembles package insertPublished annuallyDrug Evaluations – published annually by the AMA50-27Sources of Drug InformationUSP/NF Official source of drug standardsPublished about every 5 yearsAHFS – published by the American Society of Hospital Pharmacists 50-28The FDA Regulatory FunctionNew drugsClinical trials Safety EfficacyDrug manufacturingIdentityStrengthPurityQuality OTC drugsPrescription drugsPregnancy categories ABCDX50-29Controlled SubstancesDrugs categorized as potentially dangerous and addictive Strictly regulated by federal lawsComprehensive Drug Abuse Prevention and Control Act (1970)Created the DEAStrengthened drug enforcement authoritySchedules – based on abuse potential50-30ScheduleAbuse PotentialExampleIHighHeroinIIHighMorphineIIILower than II (moderate dependence)Butabarbital IVLower than III (limited dependence)Diazepam VLower than IV (very limited dependence)Antidiarrheals Controlled Substances (cont.)50-31Controlled Substances (cont.)Comprehensive Drug Abuse Prevention and Control Act (1970)Controlled substance labelingDoctor registrationOrdering controlled substancesDrug securityRecord keepingDispensing recordsInventory recordsDisposal of drugs50-32Writing PrescriptionsParts of a prescriptionSuperscriptionPatient information InscriptionName of the drugAmount of drug per doseSubscription – directions to the pharmacistSignature – patient instructions50-33Writing Prescriptions (cont.)Prescription for a single medication 50-34Writing Prescriptions (cont.)Prescription for multiple medications50-35Writing Prescriptions (cont.)Keep prescription blanks secureTelephone prescriptionsOnly at request of the physicianFollow facility policyDocument carefully50-36Apply Your KnowledgeWhich of the following sources of drug information is most like the package insert?A. AHFS B. PDR C. USP/NF D. Drug EvaluationsANSWER:Match ___ Contains the patient information A. Subscription___ Name of the drug and dosage B. Signature___ Instructions to the pharmacist C. Superscription___ Patient instructions D. InscriptionCDBAANSWER:Correct! 50-37VaccinesSpecial preparations made from microorganismsAdministered to produce reduced sensitivity to or increased immunity to an infectious diseaseBody creates antibodies in response to an antigen (vaccine)50-38Antibody FormationAntigen enters body White cells produce antibodies Antibodies combine with antigens to neutralize them This arrests or prevents reaction or diseaseVaccines stimulate antibody formation and reduce symptoms if patient is exposed to disease50-39ImmunizationsSchedule for immunizations for children up to age 16 yearsPre-exposure immunizationsPost-exposure immunizations – antiserum or antitoxin that contains antibodies50-40Immunizations (cont.)Medical assistant should be familiar withIndicationsContraindicationsDosages Administration routesPotential adverse effectsMethods of storing and handling50-41Apply Your KnowledgeANSWER: Vaccines are administered to a person to produce reduced sensitivity to or increase immunity to an infectious disease.Why are vaccines given to patients?Very Good!50-42Patient Instruction on MedicationsMedical assistant role is importantOTC drugsShould not be used to avoid medical careMay not produce enough therapeutic benefitMay be dangerous in combination with other substances or drugsMay mask symptoms or aggravate a problem50-43Patient Instruction on Medications (cont.)Prescription drugsInform patient about special considerations and drug safety precautionsEncourage patient toMaintain a complete list of medications Report adverse reactions Patient compliance50-44Patient Instruction on Medications (cont.)To prevent medication errors, be sure patient understands prescriptionHow and when to take the medicationAppropriate languageDemonstrate if necessaryReview warnings about the medication50-45Apply 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!50-46In Summary50.1 The five categories of pharmacology include pharmacognosy, pharmacokinetics, pharmacodynamics, pharmacotherapeutics, and toxicology. 50.2 The 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.50-47In Summary (cont.)50.3 Drug 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 50-2. 50.4 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 www.rxlist.com, or at other reliable Internet sites.50-48In Summary (cont.)50.5 Nonprescription or over-the-counter drugs can be obtained without a physician’s order. For prescription drugs, patients must have a physician’s order. 50.6 For 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.50-49In Summary (cont.)50.7 All 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.50.8 Receiving and telephoning medication refills is frequently done by the medical assistant for all medications except schedule II and III drugs. 50-50In Summary (cont.)50.9 Immunizations 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. 50.10 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. 50-51End of Chapter 50It is easy to get a thousand prescriptions but hard to get one single remedy.  ~Chinese Proverb