Introduction to Pharmacology.pptx

Introduction to pharmacology for nursing students

1. Introduction to Pharmacology Mrs.Nagamani.T MSc (N)

2. Objective Upon completion of the topic the health care professionals understands the importance of safe administration of medications and appreciate the knowledge about the actions and effects of medications to safely and accurately administer medications and understands about pharmacologic principles.

3. Contents Introduction to pharmacology Definitions Sources Terminology used Types: Classification Pharmacodynamics : Actions, therapeutic Adverse, toxic Pharmacokinetics : absorption, distribution, metabolism, interaction, excretion Review: Routes and principles of administration of drugs Indian pharmacopoeia : Legal issues Rational use of drugs Principles of therapeutics

4. Introduction Pharmacology is the study of drugs including their origins, history, uses, and properties.  The word pharmacology comes from the Greek words  pharmakos , meaning medicine or drug, and  logos , meaning study. Drug therapy plays a major role in the treatment of patients. It involves the use of drugs to prevent, diagnose or cure disease processes or to relieve signs and symptoms without curing the underlying disease.

5. Definitions Pharmacology  is the scientific study of the effects of drugs and chemicals on living organisms where a drug can be broadly defined as any chemical substance, natural or synthetic, which affects a biological system.  Pharmacology is the science that deals with the study of drugs and their interactions with the living system. Pharmacology is the science that deals with drugs, their sources, nature and properties.

6. Sources of drugs Drugs are substances that are used or intended to be used in the diagnosis, prevention, treatment or cure of diseases. The major sources of drugs can be grouped into the following; Plant Sources plant source for drugs are the leaf and other parts of plants (e.g., barks, fruits, roots, stem, wood, seeds, blossoms, bulb etc.)  Plant part Drugs Leaves Digoxin , digitoxin (from  Digitalis purpurea /foxglove plant ); atropine (from  Atropa belladonna ) Flowers Vincristine , vinblastine (from  Vinca rosea ) Fruits Physostigmine (from  Physostigma venenosum / calabar bean) Seeds Strychnine (from  Nux vomica ); physostigmine (from  Physostigma   venenosum / calabar bean) Roots Emetine (from  Cephaelis ipecacuanha ); reserpine (from  Rauwolfa serpentina ) Bark Quinine (from  Cinchona ); atropine (from  Atropa belladonna ) Stem Tubocurarine (from  Chondrodendron tomentosum )

7. 2. Animal Sources Medicinal substances are derived from the animal’s body secretions, fluid or glands. Insulin, heparin, adrenaline, thyroxin, cod liver oil, musk, beeswax, enzymes, and antitoxins sera are some examples of drugs obtained from animal sources.  3. Microbial sources Several life-saving drugs have been historically derived from microorganisms. Examples include penicillin produced by  Penicillium chrysogenum , streptomycin from  Streptomyces griseus,  chloramphenicol from  Streptomyces venezuelae,  neomycin from  Streptomyces fradiae,  bacitracin from  Bacillus subtilis  etc.

8. 4. Marine source Bioactive compounds from marine flora and fauna have extensive past and present use in the prevention, treatment or cure of many diseases. Coral, sponges, fish, and marine microorganisms produce biologically potent chemicals with interesting anti-inflammatory, anti-viral, and anticancer activity.  5. Mineral sources Minerals (both metallic and non-metallic minerals) have been used as drugs since ancient times. Examples include ferrous sulfate in iron deficiency anemia; magnesium sulfate as purgative; magnesium trisilicate , aluminum hydroxide and sodium bicarbonate as antacids for hyperacidity and peptic ulcer; zinc oxide ointment as skin protectant , in wounds and eczema; gold salts ( solganal , auranofin ) as anti-inflammatory and in rheumatoid arthritis; selenium as anti-dandruff.

9. 6. Synthetic/chemical derivative A synthetic drug is produced using chemical synthesis, which rearranges chemical derivatives to form a new compound. Examples include acetylsalicylic acid (aspirin or ASA), oral antidiabetics, antihistamines, thiazide diuretics, chloroquine, chlorpromazine, general and local anaesthetics, paracetamol, phenytoin etc.

10. 7. Semi-synthetic Sources Semi-synthetic drugs are neither completely natural nor completely synthetic. They are a hybrid and are generally made by chemically modifying substances that are available from natural source to improve its potency, efficacy and/or reduce side effects.  Examples of semi-synthetic medicine include heroin from morphine, bromoscopolamine from scopolamine, homatropine from atropine, ampicillin from penicillin etc.

11. 8. Biosynthetic sources (genetically engineered drugs) This is relatively a new field which is being developed by mixing discoveries from molecular biology, recombinant DNA technology, DNA alteration, gene splicing, immunology, and immune pharmacology. Drugs developed using living organisms with the help of biotechnology or genetic engineering are known as biologics, biopharmaceuticals, recombinant DNA expressed products, bioengineered, or genetically engineered drugs Examples include recombinant Hepatitis B vaccine, recombinant insulin and others.

12. Pharmacologic Principles

13. Drug Names Chemical name Describes the drug’s chemical composition and molecular structure Generic name (nonproprietary name) Name given by the United States Adopted Name Council Trade name (proprietary name) The drug has a registered trademark; use of the name restricted by the drug’s patent owner (usually the manufacturer)

14. Drug Names (cont'd) Chemical name (+/-)-2-(p-isobutylphenyl) propionic acid Generic name ibuprofen Trade name Motrin®, Advil®

15. Pharmacological Concepts: Classification Classification- Nurses learn to categorize meds with similar characteristics by their class Medication classification indicates the effect of the med on the body system, the symptom the med relieves, or the med’s desired effect (e.g. oral hypoglycemics)

16. Pharmacological Concepts: Classification A medication may also be part of more than one class Aspirin is an analgesic, antipyretic, anti-inflammatory, and anti-platelet

17. Pharmacological concepts: Medication forms Medications are available in a variety of forms and preparations The form of the med will determine its route of administration Composition of med is designed to enhance its absorption & metabolism Many meds are available in several forms

18. Medication Forms Tablet Capsule Elixir Enteric-coated Suppository Suspension Transdermal patch

19. Pharmacologic Principles Pharmaceutics Pharmacokinetics Pharmacodynamics Pharmacotherapeutics Pharmacognosy

20. Pharmaceutics The study of how various drug forms influence pharmacokinetic and pharmacodynamic activities

21. Pharmacokinetics • The study of what the body does to the drug Absorption Distribution Metabolism Excretion

22. Pharmaco dynamics • The study of what the drug does to the body The mechanism of drug actions in living tissues

23. Figure 2-2 Phases of Drug Activity. (From McKenry LM, Salerno E: Mosby’s pharmacology in nursing—revised and updated, ed 21, St. Louis, 2003, Mosby.)

24. Pharmacotherapeutics The use of drugs and the clinical indications for drugs to prevent and treat diseases

25. Pharmacognosy The study of natural (plant and animal) drug sources

26. Pharmacokinetics: Absorption The rate at which a drug leaves its site of administration, and the extent to which absorption occurs Bioavailability Bioequivalent

27. Factors That Affect Absorption Administration route of the drug Ability of Med to Dissolve Food or fluids administered with the drug Body Surface Area Status of the absorptive surface Rate of blood flow to the small intestine Lipid Solubility of Med Status of GI motility

28. Routes of Administration A drug’s route of administration affects the rate and extent of absorption of that drug Enteral (GI tract) Parenteral Topical

29. Enteral Route Drug is absorbed into the systemic circulation through the oral or gastric mucosa, the small intestine, or rectum Oral Sublingual Buccal Rectal

30. Parenteral Route Intravenous (fastest delivery into the blood circulation) Intramuscular Subcutaneous Intradermal Intrathecal Intraarticular

31. Topical Route Skin (including transdermal patches) Eyes Ears Nose Lungs (inhalation) Vagina

32. Distribution The transport of a drug in the body by the bloodstream to its site of action Protein-binding Water soluble vs. fat soluble Blood-brain barrier Areas of rapid distribution: heart, liver, kidneys, brain Areas of slow distribution: muscle, skin, fat

33. Metabolism (Also Known As Biotransformation) The biologic transformation of a drug into an inactive metabolite, a more soluble compound, or a more potent metabolite Liver (main organ) Kidneys Lungs Plasma Intestinal mucosa

34. Metabolism/Biotransformation (cont'd) Delayed drug metabolism results in: Accumulation of drugs Prolonged action of the drugs Stimulating drug metabolism causes: Diminished pharmacologic effects

35. Excretion The elimination of drugs from the body Kidneys (main organ) Liver Bowel Biliary excretion Enterohepatic circulation

36. 1. You are caring for a client who has diabetes complicated by kidney disease. You will need to make a detailed assessment when administering medications because this client may experience problems with: A. Absorption B. Biotransformation C. Distribution D. Excretion 35 - 37

37. Pharmacodynamics Study of the mechanism of drug actions in living tissue Drug-induced alterations to normal physiologic function Positive change-Therapeutic effect-Goal of therapy

38. Mechanism of Action Ways in which a drug can produce a therapeutic effect The effects that a particular drug has depends on the cells or organ targeted by the drug Once the drug hits its “site of action” it can modify the rate at which a cell or tissue functions

39. Mechanism of Action Receptor Interaction Enzyme Interaction Non-Specific Interaction

40. Receptor Interaction Drug structure is essential Involves the selective joining of drug molecule with a reactive site on the cell surface that elicits a biological effect Receptor is the reactive site on a cell or tissue Once the substance binds to and interacts with the receptor, a pharmacologic response is produced

41. Receptor Interaction Affinity- degree to which a drug binds with a receptor The drug with the best “fit” or affinity will elicit the best response Drug can mimic body’s endogenous substances that normally bind to receptor site Drugs that bind to receptors interact with receptors in different ways to either block or elicit a response

42. Receptor Interaction Agonist-Drug binds to receptor-there is a response (Adrenergic Agents) Antagonist-drug binds to receptor-no response-prevents binding of agonists (Alpha & Beta Blockers)

43. Enzyme Interaction Enzymes are substances that catalyze nearly every biochemical reaction in a cell Drugs can interact with enzyme systems to alter a response Inhibits action of enzymes-enzyme is “fooled” into binding to drug instead of target cell Protects target cell from enzyme’s action (ACE Inhibitors)

44. Non-Specific Interaction Not involving a receptor site or alteration in enzyme function Main site of action is cell membrane or cellular process Drugs will physically interfere or chemically alter cell process Final product is altered causing defect or cell death Cancer drugs, Antibiotics

45. The nurse is giving a medication that has a high first-pass effect. The physician has changed the route from IV to PO. The nurse expects the oral dose to be: 1. Higher because of the first-pass effect. 2. Lower because of the first-pass effect. 3. The same as the IV dose. 4. Unchanged.

46. . A patient is complaining of severe pain and has orders for morphine sulfate. The nurse knows that the route that would give the slowest pain relief would be which route? 1. IV 2. IM 3. SC 4. PO

47. Type of Medication Action Therapeutic Effect Side Effects Adverse Effects Toxic Effect Idiosyncratic Reactions Allergic Reaction Medication Interactions Iatrogenic Response

48. Therapeutic Effect The expected or predictable physiological response a medication causes A single med can have several therapeutic effects (Aspirin) It is important for the nurse to know why med is being prescribed

49. Side Effects Unintended secondary effects a medication predictably will cause May be harmless or serious If side effects are serious enough to negate the beneficial effect of meds therapeutic action, it may be D/C’d People may stop taking medications because of the side effects

50. Adverse Effects Undesirable response of a medication Unexpected effects of drug not related to therapeutic effect Must be reported to FDA Can be a side effect or a harmful effect Can be categorized as pharmacologic, idiosyncratic, hypersensitivity, or drug interaction

51. Adverse Effects Adverse Drug Events Adverse Drug Reactions (ADR)

52. Toxic Effect May develop after prolonged intake or when a med accumulates in the blood because of impaired metabolism or excretion, or excessive amount taken Toxic levels of opioids can cause resp.depression Antidotes available to reverse effects

53. Idiosyncratic Reactions Unpredictable effects-overreacts or under reacts to a medication or has a reaction different from normal Genetically determined abnormal response Idiosyncratic drug reactions are usually caused by abnormal levels of drug-metabolizing enzymes (deficiency or overabundance)

54. Allergic Reaction Unpredictable response to a medication Makes up greater than 10% of all medication reactions Client may become sensitized immunologically to the initial dose, repeated administration causes an allergic response to the med, chemical preservative or a metabolite

55. Allergic Reaction Medication acts as an antigen triggering the release of the body’s antibodies May be mild or severe Among the different classes of meds, antibiotics cause the highest incidence of allergic reaction Severe reaction-Anaphylactic reaction Mild reaction-hives, rash, pruritis

56. 2. A postoperative client is receiving morphine sulfate via a PCA. The nurse assesses that the client’s respirations are depressed. The effects of the morphine sulfate can be classified as: A. Allergic B. Idiosyncratic C. Therapeutic D. Toxic 35 - 62

57. Other Drug Reactions Teratogenic-Structural effect in unborn fetus (thalidomide) Carcinogenic-Causes cancer Mutagenic- Changes genetic composition (radiation, chemicals)

58. Drug Interactions Occurs when one med modifies the action of another Common in people taking several medications at once One med may potentiate or diminish the action of another or alter the way it is absorbed, metabolized or eliminated Warfarin and Amiodarone

59. Iatrogenic Responses Unintentional adverse effects that occur during therapy Treatment-Induced Dermatologic-rash, hives, acne Renal Damage-Aminoglycoside antibiotics, NSAIDS, contrast medium Blood Dyscrasias- Destruction of blood cells (Chemotherapy) Hepatic Toxicity-Elevated liver enzymes (hepatitis-like symptoms)

60. Synergistic Effect Effect of 2 meds combined is greater than the meds given separately Alcohol & Antihistamines, antidepressants, barbiturates, narcotics Not always undesirable, physician may combine meds to create an interaction that will have beneficial effects (Vasodilators & diuretics to control high BP)

61. Medication Dose Responses Except when administered IV, meds take time to enter bloodstream The quantity & distribution of med in different body compartments change constantly Goal is to keep constant blood level within a safe therapeutic range Repeated doses are required to achieve a constant therapeutic concentration of a med because a portion of med is always being excreted

62. Medication Dose Responses Serum Half-Life:Time it takes for excretion processes to lower the serum medication concentration by ½ Regular fixed doses must be given to maintain therapeutic concentration Dosage schedules set by institutions (TID, q8h, HS, AC, STAT, PRN) Peak & Trough levels Therapeutic drug monitoring

63. Half-life The time it takes for one half of the original amount of a drug in the body to be removed A measure of the rate at which drugs are removed from the body

64. Onset, Peak, and Duration Onset The time it takes for the drug to elicit a therapeutic response Peak The time it takes for a drug to reach its maximum therapeutic response Duration The time a drug concentration is sufficient to elicit a therapeutic response

65. Pharmaco therapeutics: Types of Therapies Acute therapy Maintenance therapy Supplemental therapy Palliative therapy Supportive therapy Prophylactic therapy Empiric therapy

66. Monitoring The effectiveness of the drug therapy must be evaluated One must be familiar with the drug’s: Intended therapeutic action (beneficial) Unintended but potential side effects (predictable, adverse reactions)

67. Monitoring (cont'd) • Therapeutic index – The ratio between a drug’s therapeutic benefits and its toxic effects

68. Monitoring (cont'd) • Tolerance – A decreasing response to repetitive drug doses

69. Monitoring (cont'd) • Dependence – A physiologic or psychological need for a drug

70. Monitoring (cont'd) Interactions may occur with other drugs or food Drug interactions: the alteration of action of a drug by: Other prescribed drugs Over-the-counter medications Herbal therapies

71. Monitoring (cont'd) • Drug interactions – Additive effect – Synergistic effect – Antagonistic effect – Incompatibility

72. Monitoring (cont'd) Medication misadventures Adverse drug events Adverse drug reactions Medication errors

73. Monitoring (cont'd) Some adverse drug reactions are classified as side effects Expected, well-known reactions that result in little or no change in patient management Predictable frequency The effect’s intensity and occurrence are related to the size of the dose

74. Adverse Drug Reaction An adverse outcome of drug therapy in which a patient is harmed in some way Pharmacologic reactions Idiosyncratic reactions Hypersensitivity reactions Drug interactions

75. Other Drug-Related Effects Teratogenic Mutagenic Carcinogenic

76. Toxicology The study of poisons and unwanted responses to therapeutic agents

77. Table 2-9 Common Poisons and Antidotes

78. INDIAN PHARMACOPOEIA The Indian Pharmacopoeia (IP) is a compilation of official standards for drugs manufactured in India . Standards in the IP are expressed in the form of specifications and test methods for determining compliance with such standards. The pharmacopoeias or formularies contain a list of drugs and other related substances regarding their source, descriptions, standards, tests, formulae for preparing the same, action and uses, doses, storage conditions etc

79. Indian Pharmacopoeia (IP) is published by the Indian Pharmacopoeia Commission (IPC) on behalf of the Ministry of Health & Family Welfare, Government of India in fulfillment of the requirements of the Drugs and Cosmetics Act, 1940 and Rules 1945 there under. IP is recognized as the official book of standards for the drugs being manufactured and/or marketed in India. IP contains a collection of authoritative procedures of analysis and specifications of drugs for their identity, purity and strength. The standards of the IP are authoritative in nature and are enforced by the regulatory authorities for ensuring the quality of drugs in India. During quality assurance and at the time of dispute in the court of law the IP standards are legally acceptable.

80. 1946- Indian Pharmacopoeial List was published by Govt. of India. 1955 -First edition of Indian Pharmacopoeia was published. 1960 -Supplement of IP 1955 was published . 1966 - Second edition of IP was published. 1975 -Supplement of IP 1966 was published. 1985- Third edition of IP was published. 1989 -Addendum-I to IP 1985 was published. 1991 -Addendum-II to IP 1985 was published . 1996 -Fourth edition of IP was published followed by its addendum 2000, supplement 2000 for Veterinary Products, addendum 2002 and addendum 2005; Indian Pharmacopoeia 2007 - Fifth edition, followed by addendum 2008; Indian Pharmacopoeia 2010 - Six edition with DVD followed by its addendum 2012; Indian Pharmacopoeia 2014 – Seventh edition with DVD followed by its addendum 2015 and addendum 2016; Indian Pharmacopoeia 2018 with DVD - Eighth edition

81. Medication Errors: Preventing and Responding

82. Medication Misadventures Medication errors (MEs) Adverse drug events (ADEs) Adverse drug reactions (ADRs)

83. Medication Misadventures (cont'd) By definition, all ADRs are also ADEs But all ADEs are not ADRs Two types of ADRs Allergic reactions Idiosyncratic reactions

84. Medication Errors Preventable Common cause of adverse health care outcomes Effects can range from no significant effect to directly causing disability or death

85. Box 5-1 Common classes of medications involved in serious errors

86. Preventing Medication Errors Minimize verbal or telephone orders Repeat order to prescriber Spell drug name aloud Speak slowly and clearly List indication next to each order Avoid medical shorthand, including abbreviations and acronyms

87. Preventing Medication Errors (cont'd) Never assume anything about items not specified in a drug order (i.e., route) Do not hesitate to question a medication order for any reason when in doubt Do not try to decipher illegibly written orders; contact prescriber for clarification

88. Preventing Medication Errors (cont'd) NEVER use “trailing zeros” with medication orders Do not use 1.0 mg; use 1 mg 1.0 mg could be misread as 10 mg, resulting in a tenfold dose increase

89. Preventing Medication Errors (cont'd) ALWAYS use a “leading zero” for decimal dosages Do not use .25 mg; use 0.25 mg .25 mg may be misread as 25 mg “.25” is sometimes called a “naked decimal”

90. Preventing Medication Errors (cont'd) Check medication order and what is available while using the “5 rights” Take time to learn special administration techniques of certain dosage forms

91. Preventing Medication Errors (cont'd) Always listen to and honor any concerns expressed by patients regarding medications Check patient allergies and identification Medication Reconciliation

92. Medication Errors Medication error has the potential to lead to harm to the patient. It is the leading cause of threatens trust in the healthcare system, induce corrective therapy, and prolong patients’ hospitalization, produces extra costs and even death . Possible consequences to nurses Reporting and responding to MEs ADE monitoring programs USPMERP (United States Pharmacopeia Medication Errors Reporting Program) MedWatch , sponsored by the FDA Institute for Safe Medication Practices (ISMP) Notification of patient regarding MEs

93. 3. Nurses are legally required to document medications that are administered to clients. The nurse is mandated to document: A. Medication before administering it B. Medication after administering it C. Rationale for administering the medication D. Prescriber’s rationale for prescribing the medication 35 - 99

94. 4. If a nurse experiences a problem reading a physician’s medication order, the most appropriate action will be to: A. Call the physician to verify the order. B. Call the pharmacist to verify the order. C. Consult with other nursing staff to verify the order. D. Withhold the medication until the physician makes rounds. 35 - 100

95. Administer medications safely