Pharmacology

1. Pharmacology 2011

2. Intro to Pharmacology Welcome to Pharmacology Pharmacology means “medicine” and “study” essentially the study of medicine Pharmacology is a discipline devoted to patient therapy though the use of drugs. It is an expansive topic utilizing concepts from human biology, pathophysiology, and chemistry.

3. pharmacology and therapeutics Therapeutics is the discipline dealing with the treatment of suffering and the prevention of disease. Pharmacotherapeutics is the useful application of drugs for the purpose of fighting disease. Both areas are at the core of the nursing profession.

4. Therapeutic agents may be classified as traditional drugs, biologics or alternative therapies. Drugs are chemical agents used to treat diseases in the body. Biologic drugs are substances produced naturally by a living organism. Alternative therapies involve herbal supplements and certain techniques deemed to be less conventional.

5. RX vs OTC Drugs are available by prescription or as over the counter (OTC) medication. There are two major methods of dispensing drugs: purchase of prescriptions drugs with a physician’s order and purchase of OTC drugs which do not require a physician’s order.  There are advantages and disadvantages to both methods of dispensing.

6. FDA Food and Drug Administration (FDA) was an agency established by the U.S. Department of Health and Human Services to help regulate over prescription drugs, OTC drugs, as well as medical devices. Drug approval involves four stages: pre-clinical investigation, clinical investigation, submission of a New Drug Application with review, and post-marketing surveillance. Clinical phase trials must be completed before drugs are approved for public use.

7. Drug Classes and Schedules Drugs may be organized by their therapeutic or pharmacologic classification. Two common ways to classify drugs are by therapeutic classification and pharmacological classification. Therapeutic classes are based on a drug’s clinical usefulness. Pharmacological classes are based on a drug’s mechanism of action. Prototype drugs are used to compare drugs within the same classification.

8. chemical, generic, and trade names Drugs may be described by a chemical, generic or trade name. Chemical names are precise but complicated and difficult to remember. Drugs have only one generic name that is usually short and easy to remember. The company marketing the drug assigns trade names. Drugs may have multiple trade names.

9. Generic and Brand name Generic drugs are less expensive than brand name drugs, but they may differ in their bioavailability. Generic drugs are less expensive and may be substituted for brand named products in most states if the prescriber does not object. Generic drugs may differ from their trade name counterparts with respect to their bioavailability. This may affect the safety and effectiveness of drug therapy.

10. Controlled Substances Scheduled Drugs I High Abuse Potential High Physical Dependence High Psychological Dependence Heroin, LSD, Marijuana II ex. Morphine, PCP, cocaine, methadone used therapeutically with prescription

11. Controlled Substances Scheduled Drugs III Moderate Abuse Potential Moderate Physical Dependence High Physiological Dependence ex. Anabolic steroids, codeine, hydrocodone, some barbituates IV Lower/Lower/Lower V Lowest/Lowest/Lowest ex. OTC cough medicines with codeine

12. Principles of Drug Administration Allergic Reaction: acquired hyperresonance of body defenses to a foreign substance (allergen). Anaphylaxis: severe type of allergic reaction that involves the massive, systemic release of histamine and other chemical mediators of inflammation that can lead to life-threatening shock. Side Effects vs Adverse Effects

13. Fatal Drug Reactions Toxic Epidermal Necrolysis (TEN) Widespread epidermal sloughing Epidermal detachment of skin and mucous membranes Multisystem organ involvement Assoc. with anticonvulsants, Abs, and other drugs dilantin, carbamazepine, Bactrim

14. Fatal Drug Reactions Stevens-Johnson Syndrome Causes similar to those that cause TEN Begins within the first 1-14 days of pharmacotherapy Starts as signs of URI with chills, fever and malaise Generalized blisterlike lesions follow within a few days Skin sloughing of 10% of the body

15. Three Checks – Safety First Three checks of drug administration: Checking the drug with MAR or the medication information system when removing it from the medication drawer, refrigerator or controlled substance locker. Checking the drug when preparing it, pouring it, taking it out of the unit-dose container, or connecting the IV tubing to the bag. Checking the drug before administering to the client.

16. Five Rights of Drug Adminstration Right client (2 patient identifiers) Right medication Right dose Right route of administration Right time of Delivery Bonus: Right Allergy

17. Principles of Drug Administration The nurse must have a comprehensive knowledge of the actions and side effects of drugs before they are administered. The nurse assumes great responsibility for drug administration. A firm knowledge of pharmacology is required before a drug is administered. This understanding takes into account the actions and side effects of the drug as well as the physical and emotional needs of each patient.

18. Compliance/Orders Compliance: taking medication in the manner prescribed by the practitioner, or in the case of OTC drugs, following the instructions on the label. STAT order: Refers to any medication that is needed immediately. ASAP: Available within 30 minutes

19. Compliance For pharmacologic compliance, the patient must understand and personally accept the value associated with the prescribed drug regimen. Understanding the reasons for noncompliance can help the nurse increase the success of pharmacotherapy. The nurse may be conscientious regarding all of the principles of medication administration but these strategies are of little value unless the patient agrees that the prescribed medication regimen is personally worthwhile. The nurse must understand factors which decrease compliance such as expense, annoying side effects, and self-dosing with the medication.

20. Medication Orders Single Order: Only once PRN: As needed basis Routine orders: carried out within two hours of the time it is ordered by the physician. Standing order: Written in advance of a situation that is carried out under specific circumstances. Ex. Tylenol 325 mg PO Q 6hrs PRN headache

21. Systems of Measurement Systems of measurement used in pharmacology include the metric, apothecary, and household systems. Doses are usually written in terms of the metric system such as milligrams or milliliters. The older apothecary system is rarely used. The household system (which employs the teaspoon and tablespoon method) remains in common use. Therefore, the nurse must be able to convert between the apothecary and metric systems.

22. Administering Drugs Routes Parental Drug Administration Enteral Drug Administration Transdermal, opthalmic Topical Drug Administration Otic, nasal, vaginal, rectal

23. Key Points Must have a comprehensive knowledge of the actions and side effects of drugs before they are administered to limit the number and severity of adverse drug events. The 5 rights and 3 checks are guidelines for safe drug administration which is a collaborative effort between nurses, physicians, and other healthcare professionals.

24. Enteral Route The enteral route includes medications given orally and those administered through nasogastric or gastrostomy tubes. Oral medication administration through tablet, capsule, and liquid formulation is the most common, convenient, and usually, the least costly of all the routes. Absorption is generally slow and the drug must be stable in the presence of digestive enzymes. The sublingual and buccal routes are enteral routes less commonly used.

25. Topical Drugs Topical drugs are applied locally to the skin or membranous linings of the eye, ear, nose respiratory tract, urinary tract, vagina and rectum. Topical medications may be applied for either topical or systemic effects. Most topical routes provide for slow absorption, thus they produce few systemic side effects. Topical routes include dermatologic, instillation, and inhalation.

26. Parenteral Parental administration is the dispensing of medications via a needle, usually into the skin layers (ID), subcutaneous (SQ), intramuscularly (IM), and into veins (IV). Parenteral administration results in a rapid onset of drug action. Because of the possibility of introducing microbes directly into the body, parenteral routes are considered invasive and require aseptic technique. Parenteral administration includes the ID, SC, IM, and IV routes. 

27. Pharmacokinetics Pharmacokinetics focuses on the movement of drugs throughout the body after they are administered. Pharmacokinetics is an area of pharmacology dealing with how drugs are handled by the body. It describes the barriers that drugs must penetrate to achieve therapeutic success. The four components of pharmacokinetics are: absorption, distribution, metabolism, and excretion.

28. Pharmacokinetics The physiological properties of plasma membranes determine movement of drugs throughout the body. To be distributed to body tissues, drugs use diffusion and active transport to cross biological membranes. Drugs that are small, uncharged, and lipid soluble are distributed more completely than those that are large, ionized, and water-soluble.

29. Absorption and its rate Absorption is the process of moving a drug from the site of administration to the bloodstream. Many factors affect drug movement including the type of drug formulation, drug-drug and drug-food interaction, GI and bloodstream factors, and properties of cellular membranes. Lipid solubility, ionization characteristics, and the pH of the dissolving or transport medium will also affect drug absorption.

30. Distribution Distribution: involves the transport of pharmacologic agents throughout the body> The determining factor is the distribution of the amount of blood flow to the body tissues. The heart, liver, kidneys and brain receive the most blood supply. Blood Brain Barrier Fetal-Placental Barrier

31. Distribution A drug’s distribution is affected by variables such as lipid solubility, degree of ionization, and plasma protein binding. The blood-brain and fetal-placental barriers represent areas in the body where drug distribution may be limited. Lipid-soluble and non- ionized drugs easily cross these barriers; water-soluble and ionized drugs do not.

32. Excretion Excretion processes remove drugs from the body. The kidneys, lungs, sweat glands, mammary glands, and biliary system are the major tissues eliminating drugs from the body. The main organ involved with excretion is the kidney. Enterohepatic recirculation is responsible for circulating bile and certain drugs back into the bloodstream from the gastrointestinal tract.

33. Excretion Rate at which drugs are excreted determines their concentration in the bloodstream and tissues. The concentration of the drugs in the bloodstream determines the duration of action. Pathological states such as liver disease and renal failure often increase the duration of action in the body because they interfere with the natural excretion mechanisms. Dosing must be adjusted in these cases

34. Pharmacodynamics Pharmacodynamics is the area of pharmacology concerned with how drugs produce change in patients and the differences in patient responses to medications. Pharmacodynamics explains how drugs produce changes in the body.

35. Therapeutic and Toxic Range Minimum Effective Concentration The amount of drug required to produce a therapeutic effect Toxic Concentration The level of the drug that will result in serious adverse effects Therapeutic range Plasma drug concentration between the minimum effective concentration and the toxic concentration

36. Therapeutic Index The therapeutic index is a value representing the margin of safety of a drug. The larger a medication’s therapeutic index, the greater is its margin of safety.

37. Pharmacokinetics Maintenance dose Dose given to keep the plasma drug concentration in the therapeutic range Loading dose A higher concentration of medication given to prime the blood stream with levels significant to quickly induce a therapeutic response. Half-life Length of time required for the plasma concentration of a medication to decrease by half after administration.

38. Comparing Drugs Efficacy Magnitude of maximal response that can be produced from a particular drug. Potency A drug that is more potent will produce a therapeutic effect at a lower dose, compared with another drug in the same class. Aspirin 650 mg versus Ibuprofen 200 mg Ibuprofen more potent, same efficacy

39. Potency vs Efficacy Potency relates to the dose of medication required to produce a particular response; the higher the potency, the less dose is needed to produce a response. Efficacy refers to the magnitude of maximal response: the higher the efficacy, the greater the response. In most cases, the efficacy of a drug is more important to the patient and nurse than is the potency.

40. Drug Administration Throughout the Lifespan In order to contribute to safe and effective pharmacotherapy, it is essential for the nurse to comprehend and apply fundamental concepts of growth and development. Nurses must possess an understanding of what is considered normal, in terms of growth and developmental patterns, so that deviations from the norm can be identified and health pattern impairments can be appropriately addressed. The very nature of pharmacology requires that the practitioner consider the specifics of age, growth, development, and weight in relation to pharmacokinetics and pharmacodynamics.

41. Pregnancy Pharmacotherapy during pregnancy should be conducted only when the benefits to the mother outweigh the potential risks to the fetus. Pregnancy Categories guide the practitioner in prescribing drugs for these patients. Breastfeeding patients must be aware that drugs and other substances can appear in milk and affect their infant.

42. Pregnancy Chemicals derived from foods and drugs ingested by the mother may traverse the placental barrier and affect the developing baby. An in-depth nursing and pharmacologic history and prenatal assessment are vital so that drugs can be eliminated, substituted or dosages adjusted. Pregnancy Categories have been developed by the FDA to assess potential risk to the fetus. Breast-feeding patients must be aware that drugs and other substances can appear in milk and affect their infant.

43. Pregnant Client Pregnant client Distribution and Metabolism Increase Cardiac Output Increased Blood Flow Change in regional blood flow Alterations in lipid levels Absorption Hormonal changes, pressure on blood supply Gastric emptying delayed Gastric acidity decreased Increased Resp. system

44. Pregnant Client – Teratogenic effects Pregnant client Excretion Increased kidney flow by 40% Teratogens-agents that cause fetal malformation Especially in the first trimester Lactating Client-many OTC, herbal supplements and meds are excreted in the breast milk

45. Infants During infancy, pharmacotherapy is directed toward the safety of the child and teaching the mother how to properly administer medications and care for the infant. Infants require special treatment due to their small size and their immature physiologic and biochemical processes. Mothers breastfeeding their infants must be counseled regarding the possibility of drugs entering their milk and affecting their baby.

46. Toddlers Drug administration to toddlers can be challenging. Short, concrete explanations followed by immediate drug administration are usually best for the toddler. During the toddler stage, there is a tremendous sense of curiosity and this becomes a major concern for medication safety as well as household product safety. Toddlers can swallow liquids and usually chew tablets. Restraint may be required, particularly when administering parenteral medications.

47. Preschoolers and younger school age Preschool and younger school age children can begin to assist with medication administration. During the early school years, children begin to realize the benefits of medications and the reasons why medications are needed. The nurse should give the child a sense of control over drug administration, while still being firm and giving the child praise for cooperation.

48. Adolescents Pharmacologic compliance in the adolescent is dependent upon an understanding and respect for the uniqueness of the person in this stage of growth and development. Adolescents are very concerned with physical appearance and peer approval. Common indications for pharmacotherapy in this group includes: skin conditions, headaches, menstrual irregularities, and sports injuries. The use of tobacco and illicit drugs is a major concern. The nurse should respect a teen’s need for independence and privacy.

49. Young Adults Young adults comprise the healthiest age group and generally need few prescription medications. Middle age adults begin to suffer from stress-related illness such as hypertension. Younger and middle-aged adults generally need little pharmacotherapy, relative to older adults. In females, contraception and complications associated with pregnancy are of major concern. In the middle-aged adult, cardiovascular concerns such as hypertension become important.

50. Older Adults Older adults take more medications and experience more adverse drug events than any other age group. For drug therapy to be successful, the nurse must make accommodations for age-related changes in physiological and biochemical functions. The older adult is faced with numerous physical challenges, which become targets for pharmacotherapy. Changes in liver and kidney function make pharmacotherapy more risky. Cardiovascular disease becomes a major indication for pharmacotherapy. 

51. Elderly and Medication Use Monitor for nutritional status and hydration Liver and Kidney Function Polypharmacy Safety First Compliance Reinforce

52. Herbal and Alternative Therapies Familiarize yourself with the Best-Selling Herbal Supplements pg 110 Familiriaze yourself with the most Common Herb Drug Interactions pg 113 Garlic Ginger Ginko Ginseng Kava Kava St. John’s Wort

53. Nursing Process and Pharmacology The Nursing Process is a systematic method of problem-solving and consists of clearly defined steps: assessment, establishment of nursing diagnoses, planning care through the formulation of goals and outcomes, carrying out interventions, and evaluating the care provided. The steps of the nursing process include assessment, development of nursing diagnoses, identification of goals and outcomes, planning care, implementing interventions and evaluating the plan of care. Pharmacology requires the use of the Nursing Process to ensure the best possible outcomes for the patient.

54. Assessment Assessment of the patient related to medication administration includes health history information, physical assessment data, lab values and other measurable data. It also includes an assessment of medication effects: therapeutic, side or adverse effects. Assessment is the collection of objective and subjective data. This is acquired starting with the initial health history and continues on an ongoing basis during treatment.

55. Nursing Diagnosis Nursing diagnoses are written that address the patient’s responses related to medication administration. They are developed after an analysis of the assessment data. The diagnoses are focused on the patient’s problems or potential problems and are verified with the patient or caregiver. After analyzing the assessment data, the nurse formulates patient-specific nursing diagnoses appropriate for the medications used. These diagnoses will form the basis for the other steps in the Nursing Process. Two of the most common nursing diagnoses that may be established for medication administration are knowledge deficit and noncompliance.

56. Goals Goals and outcomes are developed from the nursing diagnoses that will direct the interventions required by the plan of care. Goals focus on what the patient should be able to achieve and outcomes provide the specific, measurable criteria that nurses will use to measure goal attainment. After gathering patient assessment data and formulating nursing diagnoses, goals and outcomes are developed and priorities are established that will assist the nurse in planning care, carrying out interventions, and evaluating the effectiveness of that care. Goals and outcomes may be developed for the short-term or long-term, depending on the specific situation.

57. Interventions Interventions are aimed at returning the patient to an optimum level of wellness through the safe and effective administration of medications. Key interventions required of the nurse include monitoring drug effects, documenting medications, and patient education. Interventions are aimed at returning the patient to an optimum level of wellness and limiting adverse effects related to the patient’s condition. Key components of implementation include monitoring and documentation of drug effects, and patient education.

58. Evaluation Evaluation begins a new cycle as new assessment data is gathered and analyzed, nursing diagnoses are reviewed or rewritten, goals and outcomes refined, and new interventions are implemented. Evaluation is the final step of the Nursing Process. It considers the effectiveness of the plan of care and interventions in meeting established goals and outcomes.

59. Legal and Ethical Issues The American Nurses Association publishes a list of ethical principles that nurses can use to guide their decision making. Ethics (the moral principles guiding a person’s conduct) are learned early in life through religious affiliations, family, role models, and peers. The ANA Code of Ethics provides guidance to nurses in their professional conduct and in decision- making.

60. Legal and Ethical Issues Moral principles such as beneficence, non-maleficent behavior, veracity, autonomy, justice, and fidelity are necessary for the nurse to apply in medication administration. When making ethical decisions in clinical practice, the nurse uses fundamental moral principles. Three of the most important principles are: promote the most good for the patient (beneficence), do not harm the patient (non-maleficent behavior), and allowing the patient the informed right to choose the course of their care (autonomy).

61. Legal and Ethical Issues Nurse practice acts are enacted by every state to define the scope of practice of professional nursing and to protect the public. The State nursing practice acts define the standard of care for practicing nurses. In essence, they define what a nurse can and cannot do. Standards of care state the minimum competency for proficiency in nursing and should be consulted frequently.

62. Legal and Ethical Issues Documentation of medication administration, including any errors, should be completed immediately after the patient takes the drug. Medication use is documented in the MAR. Nurses frequently check the physician’s orders against the MAR to be certain the correct drugs have been administered.

63. medication error A medication error is a preventable error that may cause or lead to an adverse reaction to the patient. Causes may include omission of one of the “five rights” or giving medications based on verbal, illegible or incomplete orders. Medication errors can result in serious injury to the patient and litigation for the nurse and healthcare agency. The nurse must ensure that orders are carried out accurately and that every measure is taken to avoid errors.

64. medication error It is the ethical and legal responsibility of the nurse to report any medication errors that might have occurred. Documentation of medication errors is necessary for patient safety. Several national organizations contain databases of medication errors that can assist nurses and healthcare agencies formulate better policies. 9.7 Finding strategies to prevent of medication errors involves many different processes, including the nursing process. 

65. Medication Error Use of the nursing process can help reduce the number of medication errors. Nurses should work and collaborate with others on the healthcare team to develop agency policies for the storage and handling of medicines.