Pharmacology PDF

At the end of this lecture, you’ll learn:  Four Basic Terms, 1. Drug, 2. Pharmacology,...

At the end of this lecture, you’ll learn:  Four Basic Terms, 1. Drug, 2. Pharmacology, 3. Clinical Pharmacology, 4. Therapeutics,  Properties of an Ideal Drug,  Factors That Determine the Intensity of Drug ORIENTATION TO Responses, PHARMACOLOGY  Application of the Nursing Process in Drug Therapy  Drug Regulation, Development, Names, and Information Drug Pharmacology  A drug is defined as any chemical that  Pharmacology can be defined as can affect living processes. By this the study of drugs and their definition, virtually all chemicals can be considered drugs, since, when exposure interactions with living systems. is sufficiently high, all chemicals will Under this definition, have some effect on life. pharmacology encompasses the study of the physical and chemical properties of drugs as well as their biochemical and physiologic effects.  In addition, pharmacology includes knowledge of the Clinical Pharmacology history, sources, and uses of Clinical pharmacology is defined as drugs as well as knowledge of the study of drugs in humans. This drug absorption, distribution, discipline includes the study of metabolism, and excretion. drugs in patients as well as in healthy volunteers (during new drug development). PROPERTIES OF AN IDEAL DRUG Therapeutics, also known as pharmacotherapeutics, 1.The Big Three: Effectiveness, is defined as the use of drugs to Safety, and Selectivity diagnose, prevent, or treat disease or  The three most important to prevent pregnancy. Alternatively, characteristics that any drug can therapeutics can be defined simply as have are effectiveness, safety, and the medical use of drugs selectivity.  Effectiveness An effective drug is one that elicits the responses for which it  Safety is given. Effectiveness is the most important property a drug can A safe drug is defined as one that have. cannot produce harmful effects— even if administered in very high doses and for a very long time.  Alldrugs have the ability to cause  Selectivity injury, especially with high doses A selective drug is defined as one that and prolonged use. The chances of elicits only the response for which it is producing harmful effects can be given. There is no such thing as a wholly selective drug because all drugs reduced by proper drug selection cause side effects. and proper dosing ADDITIONAL PROPERTIES OF AN IDEAL 3.Predictability DRUG It would be very helpful if, before drug administration, we could know with 2.Reversible Action certainty just how a given patient will For most drugs, it is important that respond. Unfortunately, because each effects be reversible. That is, in most patient is unique, the accuracy of cases, we want drug actions to subside predictions cannot be guaranteed. within an appropriate time. General anesthetics, for example, would be useless if patients never woke up. 4. Ease of Administration An ideal drug should be simple to administer: The route should be  In addition to convenience, ease of convenient, and the number of doses per day should be low. Patients with administration has two other diabetes, who must inject insulin benefits: multiple times a day, are not likely to (1) it can enhance patient adherence, judge insulin ideal. and (2) it can decrease risk. 5.Freedom From Drug Interactions 6.Low Cost An ideal drug would be easy to afford. The cost of drugs can be a substantial financial burden. 7.Chemical Stability 8. Possession of a Simple Generic Name Some drugs lose effectiveness during storage. Others that may be stable on the Generic names of drugs are usually complex, and so they may be difficult to remember and shelf can rapidly lose effectiveness when pronounce. As a rule, the brand name for a drug put into solution (e.g., in preparation for is much simpler than its generic name. Examples infusion). of drugs that have complex generic names and simple brand names include acetaminophen [Tylenol], ciprofloxacin [Cipro], and simvastatin [Zocor]. THE THERAPEUTIC OBJECTIVE FACTORS THAT DETERMINE THE INTENSITY OF DRUG RESPONSES  The therapeutic objective of drug therapy is to provide maximum benefit with minimal harm. If drugs were ideal, we could achieve this objective with relative ease.  Administration  Pharmacokinetics The drug dosage, route, and timing of Pharmacokinetic processes determine how administration are important determinants of drug responses. Accordingly, the prescriber will much of an administered dose gets to its consider these variables with care. sites of action. There are four major pharmacokinetic processes: (1) drug absorption, (2) drug distribution, (3) drug metabolism, and (4) drug excretion.  Pharmacodynamics  Once a drug has reached its sites of  Sources of Individual Variation action, pharmacodynamic processes  Characteristics unique to each patient determine the nature and intensity of can influence pharmacokinetic and the response. pharmacodynamic processes and, by  Pharmacodynamics can be thought of doing so, can help determine the as the impact of drugs on the body. patient’s response to a drug. APPLICATION OF PHARMACOLOGY sources of individual variation include IN PATIENT CARE  physiologic variables (e.g., age, gender,  the applications of pharmacology in patient weight); care, we focus on eight aspects of drug  pathologic variables (especially therapy: diminished function of the kidneys and  (1) pre administration assessment, liver, the major organs of drug  (2) dosage and administration, elimination); and genetic variables.  (3) promoting therapeutic effects,  Genetic factors can alter the  (4) minimizing adverse effects, metabolism of drugs and can predispose the patient to unique drug reactions.  (5) minimizing adverse interactions, Because individuals differ from one  (6) making “as needed” (PRN) decisions, another, no two patients will respond  (7) evaluating responses to medication, and identically to the same drug regimen  (8) managing toxicity.  DOSAGE AND ADMINISTRATION Pre administration Assessment  The following guidelines can help  All drug therapy begins with ensure correct administration: assessment of the patient. Assessment 1. Read the medication order carefully. has three basic goals: If the order is unclear, verify it with  (1) collecting baseline data needed to the prescriber. evaluate therapeutic and adverse (i.e., 2. Verify the identity of the patient by undesired) responses, comparing the name on the wristband  (2) identifying high-risk patients, and with the name on the drug order or  (3) assessing the patient’s capacity for medication administration record. self-care. PROMOTING THERAPEUTIC EFFECTS  Drug therapy can often be enhanced by non- 3. Read the medication label carefully. pharmacologic measures. Verify the identity of the drug, the  Examples include amount of drug (per tablet, volume of  (1) enhancing drug therapy of asthma through liquid, etc.), and its suitability for breathing exercises, biofeedback, and administration by the intended route. emotional support; 4. Verify dosage calculations.  (2) enhancing drug therapy of arthritis through exercise, physical therapy, and rest; 5. Implement any special handling the and drug may require.  (3) enhancing drug therapy of hypertension 6. Don’t administer any drug if you through weight reduction, smoking cessation, don’t understand the reason for its use. and sodium restriction. MINIMIZING ADVERSE EFFECTS Minimizing Adverse Interactions To help reduce adverse effects, the nurse must know the following about the drugs she administer:  When a patient is taking two or more drugs, those drugs may interact with  The major adverse effects the drug one another to diminish therapeutic can produce effects or intensify adverse effects.  When these reactions are likely to occur.  Early signs that an adverse reaction is developing.  Interventions that can minimize discomfort and harm  As a nurse, you can help reduce the Making PRN Decisions incidence and intensity of adverse interactions in several ways:  PRN stands for pro re nata, a Latin phrase meaning as needed. A PRN medication  1. taking a thorough drug history, order is one in which the nurse has  2. advising the patient to avoid over discretion regarding when to give a drug the-counter drugs that can interact and, in some situations, how much drug to with the prescribed medication, give.  PRN orders are common for drugs that  3. monitoring for adverse promote sleep, relieve pain, and reduce interactions known to occur between anxiety. the drugs the patient is taking,  4. being alert to the possibility of as- yet-unknown interactions. EVALUATING RESPONSES TO MEDICATION Managing Toxicity  Evaluation is one of the most Some adverse drug reactions are important aspects of drug therapy. extremely dangerous. If toxicity is not  this is the process that tells us diagnosed early and responded to whether a drug is producing a benefit quickly, irreversible injury or death can or is causing harm. result. To minimize harm, you must know the early signs of toxicity and the  Because the nurse follows the procedure for toxicity management. patient’s status most closely, the nurse is in the best position to evaluate therapeutic responses.  Very often, the nurse is responsible for  Route and technique of administration educating patients about medications. In your  Expected therapeutic response and when it role as educator, you must give the patient should develop the following information:  Nondrug measures to enhance therapeutic  Drug name and therapeutic category (e.g., responses penicillin: antibiotic)  Duration of treatment  Dosage  Method of drug storage  Dosing schedule  Symptoms of major adverse effects, and measures to minimize discomfort and harm  Patient Adherence  Major adverse drug-drug and drug-food  Adherence—also known as compliance or interactions concordance—may be defined as the extent  Whom to contact in the event of therapeutic to which a patient’s behavior coincides with failure, severe adverse reactions, or severe medical advice. adverse interactions  successful therapy requires active and informed participation by the patient. By educating patients about the drugs they are taking, you can help elicit the required participation.  In its simplest form, the nursing process  Pre-administration Assessment can be viewed as a cyclic procedure that has  Pre-administration assessment establishes five basic steps: (1) assessment, (2) analysis the baseline data needed to tailor drug (including nursing diagnoses), (3) planning, therapy to the individual. By identifying the (4) implementation, and (5) evaluation variables that can affect an individual’s responses to drugs, we can adapt treatment so as to maximize benefits and minimize harm.  The drug history should include prescription drugs, over-the-counter drugs,  the analysis phase of the nursing process herbal remedies, and drugs taken for has three objectives. nonmedical or recreational purposes (e.g.,  First, you must judge the appropriateness alcohol, nicotine, caffeine, and illegal of the prescribed regimen. Second, you drugs). must identify potential health problems  adverse drug reactions should be noted, that the drug might cause. Third, you including drug allergies and idiosyncratic reactions (i.e., reactions unique to the must determine if your assessment of the individual). patient’s capacity for self-care identified an impaired ability for self-care.  Planning  Defining Goals. In all cases, the goal  Planning consists of defining goals, of drug therapy is to produce establishing priorities, identifying specific interventions, and establishing criteria for maximum benefit with minimum evaluating success. Good planning will harm. allow you to promote beneficial drug  Setting Priorities. Priority setting effects. Of equal or greater importance, requires knowledge of the drug under good planning will allow you to anticipate consideration and the patient’s unique adverse effects—rather than react to them characteristics after the fact.   Identifying Interventions. The heart of planning is identification of nursing interventions. For medication purposes,  (3) interventions to minimize adverse these interventions can be divided into four effects and interactions, and major groups:  (4) patient education  1-drug administration  2- interventions to enhance therapeutic effects  Establishing Criteria for Evaluation.  The need for objective criteria by which to measure desired drug Drug Adverse Related Nursing Diagnosi responses is obvious: Without such Effect criteria we could not determine how Ampheta CNS Disturbed sleep pattern mine stimulation related to drug-induced CNS well our drug achieved the therapeutic excitation objective. Aspirin Gastric Pain related to aspirin- erosion induced gastric erosion Atropine Urinary Urinary retention related to retention drug therapy  Implementation  Evaluation  Implementation of the care plan in drug therapy has four major components:  Over the course of drug therapy, the  (1) drug administration, patient must be evaluated for  (2) patient education,  (1) therapeutic responses,  (3) interventions to promote therapeutic  (2) adverse drug reactions and effects, and interactions,  (4) interventions to minimize adverse  (3) adherence to the prescribed effects. regimen, and  (4) satisfaction with treatment. LANDMARK DRUG LEGISLATION  The first American law to regulate drugs was the  the Food and Drug Administration Federal Pure Food and Drug Act of 1906. This law set standards for drug quality and purity in (FDA) addition to strength.  Two laws—the Best Pharmaceuticals  The Food, Drug and Cosmetic Act, passed in for Children Act (BPCA), passed in 2002, 1938, was the first legislation to address drug and the Pediatric Research Equity Act safety. (PREA) of 2003—were designed to promote much-needed research on drug efficacy and safety in children.  HAZARDOUS DRUG EXPOSURE  In 2007, Congress passed the FDA  Exposure to certain drugs can be Amendments Act (FDAAA), the most dangerous for nurses and other important legislation on drug safety since healthcare workers who handle the Harris-Kefauver Amendments of 1962. them. It is imperative to ensure your The FDAAA expands the mission of the own safety as well as the safety of FDA to include rigorous oversight of drug safety after a drug has been approved. your patients  The National Institute for Occupational Safety and Health (NIOSH) identifies a drug as hazardous for handling if it meets one or more of the following criteria:  Carcinogenicity Teratogenicity  developmental toxicity Reproductive toxicity NEW DRUG DEVELOPMENT  Organ toxicity at low doses Genotoxicity  New drugs with structure and toxicity profiles similar to drugs previously determined to be hazardous  Steps in New Drug Development Preclinical Testing (in animals) :Toxicity Pharmacokinetics, Possible Useful Effects Investigational New Drug (IND) Status  Phase III Subjects: Patients Tests: Safety and effectiveness Clinical Testing (in humans) Phase I Subjects: Healthy volunteers  Conditional Approval of New Drug Tests: Metabolism, pharmacokinetics, Application (NDA) and biologic effects Phase II Subjects: Patients Tests: Therapeutic utility and dosage  Phase IV: Postmarketing Surveillance range Limitations of the Testing Procedure DRUG NAMES  Limited Information on Women and  The Three Types of Drug Names Children (1) a chemical name,  Failure to Detect All Adverse Effects (2)a generic name, (3)a brand name  Chemical Name The chemical name constitutes a description of a drug using the nomenclature of chemistry.  For example, few people would communicate using the chemical term N-acetyl-para- aminophenol when a simple generic name (acetaminophen) or brand name (e.g., Tylenol) could be used.  Generic Name  In many cases, the final syllables of the generic name indicate a drug’s  The generic name of a drug is assigned by pharmacologic class. the United States Adopted Names Council. Each drug has only one generic name. The  For example, the syllables -cillin at the end generic name is also known as the non- of amoxicillin indicate that amoxicillin proprietary name. Generic names are less belongs to the penicillin class of complex than chemical names. antibiotics.   Brand Name Problems With Brand Names  Brand names, also known as proprietary or trade names, are the names under  A Single Drug Can Have Multiple Brand which a drug is marketed. These names Names. are created by drug companies with the  Over-the-Counter (OTC) Products With the intention that they be easy for nurses, Same Brand Name May Have Different Active physicians, pharmacists, and consumers Ingredients to recall and pronounce.  Brand Names Can Endanger International Travelers. OVER-THE-COUNTER DRUGS SOURCES OF DRUG INFORMATION  OTC drugs are defined as drugs that can be  Newsletters The Medical Letter on Drugs purchased without a prescription. These and Therapeutics is a bimonthly publication agents are used for a wide variety of that gives current information on drugs. complaints, including mild pain, motion  Reference Books sickness, allergies, colds, constipation, and  internet heartburn.