NCM 106 - Session 1 to 7.pdf Pharmacology Review PDF

NCM 106: PHARMACOLOGY REVIEWER SESSION 1 PHARMACOLOGY PRINCIPLES I. DEFINITION OF PHARMACOLOGY III. PHARMACOKINETICS Pharmacology  involves the study of absorption, distribution,  study of the biological effects of chemicals....

NCM 106: PHARMACOLOGY REVIEWER SESSION 1 PHARMACOLOGY PRINCIPLES I. DEFINITION OF PHARMACOLOGY III. PHARMACOKINETICS Pharmacology  involves the study of absorption, distribution,  study of the biological effects of chemicals. metabolism (biotransformation), and excretion (Karch, 2012) of drugs.  study of substances that interact with living systems through chemical processes, especially  ABSORPTION by binding to regulatory molecules and  the process by which a drug passes activating or inhibiting normal body processes. into the bloodstream. (Katzung, 2018)  The rate of absorption of a drug in the stomach is variable. Medical Pharmacology  The first-pass effect occurs when oral  the science of substances used to prevent, drugs first pass through the liver and diagnose, and treat disease. are partially metabolized prior to reaching the target organ. Toxicology  branch of pharmacology that deals with the undesirable effects of chemicals on living  DISTRIBUTION systems, from individual cells to humans to  involves the movement of a drug to complex ecosystems the body’s tissues.  When a drug enters the bloodstream, Clinical Pharmacology (Pharmacotherapeutics) it is carried to the most vascular  branch of pharmacology that uses drugs to organs. treat, prevent, and diagnose disease.  Clinical pharmacology addresses two key  METABOLISM concerns:  also known as “Biotransformation” or  the drug’s effects on the body “Detoxification” (Pharmacodynamics) The liver is the most important site of   the body’s response to the drug drug metabolism, or biotransformation, (Pharmacokinetics) the process by which drugs are changed into new, less active II. PHARMACODYNAMICS chemicals.  is the mechanism of drug action and the relationships between drug concentration and  EXCRETION responses in the body  Removal of the drug in the body.  Most drugs must bind to a receptor to bring  The skin, saliva, lungs, bile, and feces about an effect. are some of the routes used to excrete  Most drugs exert their effects by drugs. chemically binding with receptors at  The kidneys, however, play the most the cellular level. important role in drug excretion When a drug binds to its receptor, the pharmacologic effects are either agonism or antagonism - NICOLE CADENCE CARAAN - IV. PRINCIPLES OF DRUG 7. RIGHT DOCUMENTATION  Document medication administration ADMINISTRATION after giving it, not before. TEN “RIGHTS” OF MEDICATION ADMINISTRATION  If time of administration differs from 1. RIGHT MEDICATION prescribed time, note the time on the  The medication given was the MAR and explain the reason and medication ordered. follow-through activities (e.g., pharmacy states medication will be 2. RIGHT DOSE available in 2 hours) in nursing notes.  The dose ordered is appropriate for  If a medication is not given, follow the the client. agency’s policy for documenting the  Give special attention if the reason why. calculation indicates multiple pills/tablets or a large quantity of a 8. RIGHT TO REFUSE liquid medication.  Adult clients have the right to refuse  This can be an indication that any medication. the math calculation may be  The nurse’s role is to ensure that the incorrect. client is fully informed of the potential consequences of refusal and to  Double-check calculations that communicate the client’s refusal to appear questionable. the health care provider.  Know the usual dosage range of the medication. 9. RIGHT ASSESSMENT  Question a dose outside of the usual  Some medications require specific dosage range. assessments prior to administration (e.g., apical pulse, blood pressure, lab 3. RIGHT TIME results).  Give the medication at the right  Medication orders may include frequency and at the time ordered specific parameters for administration according to agency policy. (e.g., do not give if pulse less than 60  Medications should be given within or systolic blood pressure less than 100) the agency guidelines. 10. RIGHT EVALUATION 4. RIGHT ROUTE  Conduct appropriate follow-up (e.g.,  Give the medication by the ordered was the desired effect achieved or route. not? Did the client experience any  Make certain that the route is safe side effects or adverse reactions?). and appropriate for the client. 5. RIGHT CLIENT  Medication is given to the intended client.  Check the client’s identification band with each administration of a medication.  Know the agency’s name alert procedure when clients with the same or similar last names are on the nursing unit. 6. RIGHT CLIENT EDUCATION  Explain information about the medication to the client  Examples:  why receiving,  what to expect,  any precautions - NICOLE CADENCE CARAAN -  II. SOURCE OF DRUGS SESSION 2 Drugs are available from varied sources, both PHARMACOLOGY (PART 1) natural and synthetic. (CHAPTER 1 & 2)  Natural Sources  Plants, animals, or inorganic compounds. (To become a drug, a chemical must have a I. INTRODUCTION TO DRUGS demonstrated therapeutic value or efficacy Drugs without severe toxicity or damaging properties.)  chemicals that are introduced into the body to  Plants cause some sort of change.  an important source of chemicals that are When drugs are administered, the body begins a developed into drugs. sequence of processes designed to handle the new chemicals. For example,  These processes, which involve breaking down  digitalis used to treat and eliminating the drugs, in turn affect the cardiac disorders body’s complex series of chemical reactions.  various opiates used for sedation Nurses deal with pharmacotherapeutics, or clinical originally derived from plants. pharmacology, the branch of pharmacology that uses drugs to treat, prevent, and diagnose disease.  Drugs also may be processed  Clinical pharmacology addresses two key using a synthetic version of concerns: the active chemical found in  the drug’s effects on the body a plant. (Pharmacodynamics) An example of this type  the body’s response to the drug of drug is dronabinol (Pharmacokinetics) (Marinol) Note:  A drug can have many effects, and the nurse must know which ones may occur when a particular drug is administered. Dronabinol (Marinol)  Some drug effects are therapeutic, or helpful,  which contains the active ingredient delta-9- but others are undesirable or potentially tetrahydrocannabinol found in marijuana. dangerous.  This drug helps to prevent nausea and vomiting  These negative effects are called in cancer patients adverse effects, or side effects, of the  but does not have all the adverse drug. effects that occur when the marijuana leaf is smoked. The nurse is in a unique position regarding drug  Marijuana leaf is a controlled substance with therapy because nursing responsibilities include high abuse potential and is legal for medical the following: use in some states but not approved for  Administering drugs recreational use in most states.  Assessing drug effects  The synthetic version of the active  Intervening to make the drug regimen more ingredient allows for an accepted tolerable form to achieve the desired  Providing patient teaching about drugs and therapeutic effect in cancer patients. drug regimens  Monitoring the overall patient care plan to prevent medication errors (Continuation of - “Natural Sources”)-----------------  Animal Products  used to replace human chemicals that fail to be produced because of disease or genetic problems. - NICOLE CADENCE CARAAN -   Synthetic Sources  Scientists use genetic engineering to For deeper understanding of “Animal Products”: alter bacteria to produce chemicals that are therapeutic and effective. Until recently, insulin for treating diabetes was  For example, the cephalosporins are a obtained exclusively from the pancreas of cows large group of antibiotics derived from and pigs. the same chemical structure.  Some of these drugs cause severe Now genetic engineering (the process of altering toxic effects (e.g., renal toxicity), but DNA) permits scientists to produce human insulin by others do not. altering Escherichia coli bacteria,  making insulin a better product without some of the impurities that come with animal products. KEY POINTS:  Clinical pharmacology is the study of drugs used to treat, diagnose, or prevent a disease.  Drugs are chemicals that are introduced into (Continuation of “Natural Sources”)------------------- the body and affect the body’s chemical processes.  Inorganic Compounds  Drugs can come from plants, foods, animals,  Salts of various chemical salts of inorganic compounds, or synthetic elements can have sources. therapeutic effects in the human body.  Aluminum, fluoride, iron, and even gold are used to treat various conditions. III. DRUG EVALUATION  After a chemical that might have therapeutic  The effects of these elements usually were value is identified, it must undergo a series of discovered accidentally scientific tests to evaluate its actual when a cause–effect therapeutic and toxic effects. relationship was  This process is tightly controlled by the U.S. Food observed. and Drug Administration (FDA)  an agency of the U.S. Department of Health and Human Services that ELEMENTS USED FOR THEIR THERAPEUTIC EFFECTS regulates the development and sale Element Therapeutic Use of drugs.  Antacid to  FDA regulated tests are designed to decrease gastric ensure the safety and reliability of any acidity drug approved in this country  Management of  Before receiving final FDA approval to be Aluminum hyperphosphatemia marketed to the public, drugs must pass  Prevention of the through several stages of development. formation of  These include preclinical trials and phosphate urinary phase I, II, and III studies stones STAGES DESCRIPTION  Prevention of dental cavities  initial trial of a Fluorine (as fluoride) chemical thought  Prevention of osteoporosis to have therapeutic Preclinial Trials potential Treatment of  uses laboratory Gold rheumatoid arthritis animals, not human subjects Treatment of iron Iron deficiency anemia pilot study of a potential drug using a small Phase I Studies number of selected, usually healthy human volunteers - NICOLE CADENCE CARAAN -   The chemical is highly teratogenic  clinical study of a (causing adverse effects to a fetus). proposed drug by  The safety margins are so small that selected physicians the chemical would not be useful in using actual the clinical setting. patients who have Phase II Studies the disorder the drug is designed to B. PHASE I STUDIES treat  Uses human volunteers to test the drugs.  patients must  More tightly controlled than preclinical trials provide informed  Performed by specially trained clinical consent. investigators Note: use of a proposed drug Some chemicals are therapeutic in other animals on a wide scale in the but have no effects in humans. clinical setting with Phase III Studies patients who have the Investigators in phase I studies scrutinize the drugs disease the drug is being tested for effects in humans. thought to treat.  They also look for adverse effects and toxicity. Food and Drug At the end of phase I studies, many chemicals are *It is in the word itself* Administration Approval dropped from the process for the following reasons:  They cause unacceptable adverse effects. continuous evaluation  They are highly teratogenic. of a drug after it has  They are too toxic. Phase IV Studies  They lack evidence of potential therapeutic been released for marketing effect in humans. Some chemicals move to the next stage of testing despite undesirable effects. For example, the antihypertensive drug minoxidil was found to effectively treat malignant hypertension, but it caused unusual hair growth on the palms and other body areas. However, because it was so much more effective for treating malignant hypertension at the time of its development than any other antihypertensive drug and because the undesired effects were not dangerous, it proceeded to phase II studies. (Now, its hair-growing effect has been channeled for therapeutic use into various topical hair-growth preparations such as Rogaine.) A. PRECLINICAL TRIAL  Initial trial in which chemicals that may have C. PHASE II STUDIES therapeutic value are tested on laboratory  allows clinical investigators to try out the drug in animals (not human subjects) patients who have the disease that the drug is designed to treat. Two main purposes: 1. to determine whether they have the At the end of phase II studies, a drug may be presumed effects in living tissue removed from further investigation for the following 2. to evaluate any adverse effects reasons:  It is less effective than anticipated. At the end of the preclinical trials, some chemicals  It is too toxic when used with patients. are discarded for the following reasons:  It produces unacceptable adverse effects.  The chemical lacks therapeutic  It has a low benefit-to-risk ratio, meaning that the activity when used with living animals. therapeutic benefit it provides does not outweigh  The chemical is too toxic to living the risk of potential adverse effects that it causes.  It is no more effective than other drugs already on animals to be worth the risk of the market, making the cost of continued research developing into a drug. and production less attractive to the drug company. - NICOLE CADENCE CARAAN - D. Phase III Studies  Involves use of the drug in a vast clinical market.  Prescribers are informed of all the known reactions to the drug and precautions required for its safe use.  Prescribers observe patients very closely, monitoring them for any adverse effects.  Often, prescribers ask patients to keep F. Phase IV Studies journals and record any symptoms  continuous evaluation of a drug after it has they experience. been released for marketing Prescribers then evaluate the reported effects  Some drugs cause unexpected effects that are to determine whether they are caused by the not seen until wide distribution occurs. disease or by the drug.  Sometimes, those effects are  This information is collected by the therapeutic. drug company that is developing the For example, patients taking the drug and is shared with the FDA. antiparkinsonism drug amantadine (Symmetrel) were When a drug is used widely and within uncontrolled found to have fewer cases of environments, totally unexpected responses may influenza than other patients, occur. leading to the discovery that amantadine is an effective A drug that produces unacceptable adverse antiviral agent. effects or unforeseen reactions is usually removed from further study by the drug company. In some cases, the FDA may have to IV. LEGAL REGULATION OF DRUGS request that a drug be removed from the  The FDA regulates the development and sale market. of drugs.  Local laws further regulate the distribution and administration of drugs. E. Food and Drug Administration Approval  In most cases, the strictest law is the  Drugs that finish phase III studies are evaluated one that prevails. by the FDA, which relies on committees of  Nurses should become familiar with the rules experts familiar with the specialty area in which and regulations in the area in which they the drugs will be used. practice.  Only those drugs that receive FDA committee  These regulations can vary from state approval may be marketed. to state, and even within a state.  An approved drug is given a brand name (trade name) by the pharmaceutical company that V. SAFETY DURING PREGNANCY developed it. FOOD AND DRUG ADMINISTRATION PREGNANCY CATEGORIES  The generic name of a drug is the The FDA has established five categories to indicate the potential original designation that the drug was for a systemically absorbed drug to cause birth defects. given when the drug company  The key differentiation among the categories rests on the applied for the approval process. degree (reliability) of documentation and the risk–benefit ratio.  Chemical names are names that reflect the chemical structure of a drug. Some drugs are known by all three names.  It can be confusing to study drugs when so Adequate studies in pregnant many different names are used for the same women have not compound. demonstrated a risk to the CATEGORY A fetus in the first trimester of In this text, pregnancy, and there is no evidence of risk in later  the generic and chemical names always trimesters. appear in straight print  the brand name is always capitalized and italicized - NICOLE CADENCE CARAAN -  Animal studies have not Less abuse potential than demonstrated a risk to the schedule II drugs and fetus, but there are no moderate dependence adequate studies in pregnant SCHEDULE III (C-III) liability (nonbarbiturate women, or animal studies sedatives, nonamphetamine have shown an adverse stimulants, limited amounts of CATEGORY B effect, but adequate studies in certain narcotics) pregnant women have not demonstrated a risk to the fetus during the first trimester of Less abuse potential than pregnancy, and there is no schedule III and limited evidence of risk in later SCHEDULE IV (C-IV) dependence liability (some trimesters. sedatives, antianxiety agents, and nonnarcotic analgesics) Animal studies have shown an adverse effect on the fetus, but there are no adequate Limited abuse potential. studies in humans;  Primarily small amounts of  the benefits from the use narcotics (codeine) used of the drug in pregnant as antitussives or CATEGORY C women may be antidiarrheals. acceptable despite its  Under federal law, potential risks, or there limited quantities of are no animal certain schedule V drugs reproduction studies and may be purchased no adequate studies in SCHEDULE V (C-V) without a prescription humans. directly from a pharmacist. There is evidence of human  The purchaser must be at fetal risk, but the potential least 18 years of age and benefits from the use of the must furnish suitable CATEGORY D drug in pregnant women may identification. be acceptable despite its  All such transactions must potential risks. be recorded by the Studies in animals or humans dispensing pharmacist. demonstrate fetal abnormalities or adverse Prescribing physicians and dispensing pharmacists must be reactions; registered with the DEA, which also provides forms for the CATEGORY X  reports indicate transfer of schedule I and II substances and establishes criteria evidence of fetal risk. for the inventory and prescribing of controlled substances. The risk of use in a pregnant  State and local laws are often more stringent than federal woman clearly outweighs any law. In any given situation, the more stringent law applies. possible benefit. Regardless of the designated pregnancy category or presumed safety, no drug should be administered during pregnancy unless it is clearly needed. VII. GENERIC DRUGS  are chemicals that are produced by companies involved solely in the manufacturing of drugs. VI. CONTROLLED SUBSTANCES  Because they do not have: DRUG ENFORCEMENT AGENCY SCHEDULES OF CONTROLLED SUBSTANCES  the research, The Controlled Substances Act of 1970 regulates the  the advertising, manufacturing, distribution, and dispensing of drugs that are  or, sometimes, the quality control known to have abuse potential. departments that the pharmaceutical  The DEA is responsible for the enforcement of these companies developing the drugs regulations.  The controlled drugs are divided into five DEA schedules have, based on their potential for abuse and physical and they can produce the generic drugs more psychological dependence: cheaply. High abuse potential and no VIII. ORPHAN DRUGS SCHEDULE I (C-I) accepted medical use  drugs that have been discovered but are not (heroin, marijuana, LSD) financially viable and therefore have not been “adopted” by any drug company.  may be useful in treating a rare disease, or they may have potentially dangerous adverse High abuse potential with effects. severe dependence liability  often abandoned after preclinical trials or SCHEDULE II (C-II) (narcotics, amphetamines, phase I studies. and barbiturates) - NICOLE CADENCE CARAAN - IX. OVER-THE-COUNTER DRUGS  JOURNALS  products that are available without  Various journals can be used to obtain prescription for self-treatment of a variety of drug information. complaints.  For example, the Medical Letter is a  Although OTC drugs have been found to be monthly review of new drugs, drug safe when taken as directed, nurses should classes, and specific treatment consider several problems related to OTC drug protocols. use:  INTERNET INFORMATION  Taking these drugs could mask the  Nurses need to become familiar with what is available on the Internet and signs and symptoms of underlying disease, making diagnosis difficult. what patients may be referencing.  Taking these drugs with prescription medications could result in drug XI. DRUGS AND THE BODY interactions and interfere with drug To understand what happens when a drug is therapy. administered, the nurse must understand:  Not taking these drugs as directed  Pharmacodynamics could result in serious overdoses.  how the drug affects the body  Pharmacokinetics X. SOURCES OF DRUG INFORMATION  how the body acts on the drug. These processes form the basis for the guidelines that have been established regarding drug administration. XII. PHARMACODYNAMICS  the science dealing with interactions between the chemical components of living systems and the foreign chemicals, including drugs, that enter those systems.  Drugs usually work in one of four ways: 1. To replace or act as substitutes for missing chemicals. 2. To increase or stimulate certain cellular activities. 3. To depress or slow cellular activities.  DRUG LABELS 4. To interfere with the functioning of  Drug labels have specific information foreign cells, such as invading that identifies a specific drug. microorganisms or neoplasms. (Drugs  For example, a drug label identifies that act in this way are called the brand and generic names for the chemotherapeutic agents.) drug, the drug dosage, the expiration date, and special drug warnings. RECEPTOR SITES  PACKAGE INSERTS  Many drugs are thought to act at specific  All drugs come with a package insert areas on cell membranes called receptor sites. prepared by the manufacturer  The receptor sites react with certain according to strict FDA regulations. chemicals to cause an effect within  The package insert, or full prescribing the cell. information, contains all of the  In many situations, nearby enzymes chemical and study information that break down the reacting chemicals led to the drug’s approval. and open the receptor site for further  REFERENCE BOOKS stimulation.  A wide variety of reference books are  Some drugs interact directly with receptor sites available for drug information. to cause the same activity that natural  Example: chemicals would cause at that site.  Physician’s Drug Reference  These drugs are called agonists. (PDR),  Drug Facts and Comparisons,  AMA Drug Evaluations, and  Lippincott’s Nursing Drug Guide (LNDG) - NICOLE CADENCE CARAAN - DRUG-ENZYME INTERACTIONS DYNAMIC EQUILIBRIUM  Drugs also can cause their effects by interfering with the enzyme systems that act as catalysts for various chemical reactions.  Acetazolamide (Diamox) is a diuretic that blocks the enzyme carbonic anhydrase, which subsequently causes alterations in the hydrogen ion and water exchange system in the kidney, as well as in the eye. SELECTIVE TOXICITY  The ability of a drug to attack only those systems found in foreign cells is known as selective toxicity.  Penicillin, an antibiotic used to treat bacterial infections, has selective toxicity.  It affects an enzyme system unique to bacteria, causing  The actual concentration that a drug reaches bacterial cell death without in the body results from a dynamic equilibrium disrupting normal human cell involving the rate of several processes: functioning.  Absorption from the site of entry  Distribution to the active site  Biotransformation (metabolism) in the XIII. PHARMACOKINETICS liver  involves the study of absorption, distribution,  Excretion from the body metabolism (biotransformation), and excretion These processes are key elements in determining of drugs. the amount of drug (dose) and the frequency of  In clinical practice, pharmacokinetic dose repetition (scheduling) required to achieve considerations include the: the critical concentration for the desired length of  onset of drug action, time.  drug half-life,  timing of the peak effect, A. ABSORPTION  duration of drug effects,  refers to what happens to a drug from the time  metabolism or biotransformation of it is introduced to the body until it reaches the the drug, and the circulating fluids and tissues.  site of excretion.  Drugs can be absorbed from many different areas in the body: CRITICAL CONCENTRATION  through the GI tract  The amount of a drug that is needed to cause  either orally or rectally, a therapeutic effect.  through mucous membranes,  The recommended dose of a drug is based on  through the skin, the amount that must be given to eventually  through the lung, reach the critical concentration.  or through muscle or subcutaneous  Too much of a drug will produce toxic tissues. (poisonous) effects, and  too little will not produce the desired Routes of Administration therapeutic effects.  Drug absorption is influenced by the route of administration. LOADING DOSE 1. Oral (PO)  Some drugs may take a prolonged period to  the most frequently used drug reach a critical concentration. administration route in clinical  If their effects are needed quickly, a practice loading dose is recommended.  not invasive and is generally  Digoxin (Lanoxin), a drug used to increase the inexpensive. strength of heart contractions, and many of  The safest way to deliver drugs. the xanthine bronchodilators (e.g., theophylline) used to treat asthma attacks are often started with a loading dose (a higher dose than that usually used for treatment) to reach the critical concentration - NICOLE CADENCE CARAAN - 2. Intravenous (IV) B. DISTRIBUTION  reach their full strength at the time of  involves the movement of a drug to the body’s injection avoiding initial breakdown. tissues.  Basically, these drugs have an immediate onset and are fully Protein Binding absorbed at administration because  Drugs bind to large protein molecules it’s released in the bloodstream.  Most drugs are bound to some extent to 3. Intramuscular proteins in the blood to be carried into  absorbed directly into the capillaries in circulation. the muscle and sent into circulation.  The more bound to the protein, the  This takes time because the drug must more difficult it can be for the be picked up by the capillary and medication to be released and able taken into the veins. to cross membranes to get to the 4. Subcutaneous tissue cells.  deposit the drug just under the skin, where it is slowly absorbed into Blood-Brain Barrier circulation.  a protective system of cellular activity that  Timing depends on the fat content of keeps many things (e.g., foreign invaders, the injection site. poisons) away from the CNS. 5. Rectal (PR)  Some substances can pass the brain tissues, 6. Mucus Membrane (sublingual, buccal) some are not. 7. Topical (Skin)  Drugs that are highly lipid-soluble are 8. Inhalation more likely to pass through the blood– brain barrier and reach the CNS. Absorption Processes  Drugs that are not lipid-soluble are not Drugs can be absorbed into cells through various able to pass the blood–brain barrier. processes:  Passive diffusion Placenta and Breast Milk  major process through which drugs  Many drugs readily pass through the placenta are absorbed into the body. and affect the developing fetus in pregnant  occurs across a concentration women. gradient.  it is best not to administer any drugs to  From an area of greater pregnant women because of the concentration to lower possible risk to the fetus. concentration.  does not require any cellular energy. C. BIOTRANSFORMATION (METABOLISM)  Occurs more quickly if the drug  the process by which drugs are changed into molecule is small, soluble in water and new, less active chemicals. lipids, and has no electrical charge.  The liver is the most important site of drug  Active transport metabolism or biotransformation.  a process that uses energy to actively move a molecule across a cell First-Pass Effect membrane.  Drugs that are taken orally are usually  The molecule may be large, or it may absorbed from the small intestine directly into be moving against a concentration the portal venous system (the blood vessels gradient. that flow through the liver on their way back to  Not very important in the absorption of the heart) most drugs, but it is often a very  Portal veins deliver absorbed important in drug excretion in the molecules into the liver, which kidney. immediately transforms most of the  Filtration chemicals delivered to it by a series of  involves movement through pores in liver enzymes. the cell membrane,  These enzymes break the  either down a concentration drug into metabolites, some gradient of which are:  or as a result of the pull of  active and cause effects plasma proteins (when in the body pushed by hydrostatic, blood,  deactivated and can be or osmotic pressure). readily excreted from the  another process the body commonly body. uses in drug excretion. - NICOLE CADENCE CARAAN -  As a result, a large XV. DRUG-DRUG OR DRUG- percentage of the oral dose is destroyed at this point and ALTERNATIVE THERAPY INTERACTIONS never reaches the tissues.  Clinically significant drug–drug interactions  The portion of the drug that gets through the occur with drugs that have small margins of first-pass effect is delivered to the circulatory safety. system for transport throughout the body.  If there is very little difference between a therapeutic dose and a toxic dose Hepatic Enzyme System of the drug, interference with the  The intracellular structures of the hepatic cells drug’s pharmacokinetics or are lined with enzymes packed together in pharmacodynamics can produce what is called the hepatic microsomal system. serious problems.  Because orally administered drugs  Drug–drug interactions can occur in the enter the liver first, the enzyme systems following situations: immediately work on the absorbed  At the site of absorption: drug to biotransform it.  One drug prevents or accelerates absorption of the Enzyme Induction other drug.  The presence of a chemical that is  During distribution: metabolized by a particular enzyme system  One drug competes for the often increases the activity of that enzyme protein-binding site of system. another drug, so the second drug cannot be transported D. EXCRETION to the reactive tissue.  removal of a drug from the body.  During biotransformation:  The skin, saliva, lungs, bile, and feces are some  One drug stimulates or blocks of the routes used to excrete drugs. the metabolism of the other  The kidneys, however, play the most important drug. role in drug excretion  During excretion:  One drug competes for Glomerular Filtration excretion with the other drug,  the passage of water and water-soluble leading to accumulation and components from the plasma into the renal toxic effects of one of the tubule. drugs.  Drugs that have been made water-soluble in  At the site of action: the liver are often readily excreted from the  One drug may be an kidney by glomerular filtration. antagonist of the other drug or may cause effects that Half-Life oppose those of the other drug, leading to no  The half-life of a drug is the time it takes for the amount of drug in the body to decrease to therapeutic effect. one half of the peak level it previously achieved. XVI. DRUG-FOOD INTERACTIONS  For the most part, a drug–food interaction XIV. FACTORS INFLUENCING DRUG occurs when the drug and the food are in direct contact in the stomach. EFFECTS  Some foods increase acid production,  Weight speeding the breakdown of the drug  Age molecule and preventing absorption  Gender and distribution of the drug.  Physiological factors  Pathological factors  Genetic factors  Immunological factors  Psychological factors  Environmental factors  Tolerance  Accumulation  Interactions - NICOLE CADENCE CARAAN - XVII. DRUG-LABORATORY INTERACTIONS  This drug–laboratory test interaction is caused by the drug being given and not necessarily by a change in the body ’s responses or actions.  Keep these interactions in mind when evaluating a patient’s diagnostic tests.  If one test result is altered and does not fit in with the clinical picture or other test results, consider the possibility of a drug–laboratory test interference. XVIII. OPTIMAL THERAPEUTIC EFFECT  As overwhelming as all of this information may seem, most patients can follow a drug regimen to achieve optimal therapeutic effects without serious adverse effects.  Avoiding problems is the best way to treat adverse or ineffective drug effects. - NICOLE CADENCE CARAAN -   Being alert to adverse effects (what to assess SESSION 3 and how to intervene appropriately) can increase the effectiveness of a drug regimen, PHARMACOLOGY (PART 3) provide for patient safety, and improve patient (CHAPTER 3 & 4) compliance. I. TOXIC EFFECTS OF DRUGS IV. HYPERSENSITIVITY  All drugs are potentially dangerous.  Some patients are excessively responsive to  Even though chemicals are carefully either the primary or the secondary effects of a screened and tested in animals and in drug. people before they are released as  This is known as hypersensitivity. drugs, drug products often cause  it may result from a unexpected or unacceptable pathological or underlying reactions when they are administered. condition.  Can occur if a patient has an underlying condition that makes the drug’s effects II. ADVERSE EFFECTS especially unpleasant or dangerous.  Undesired effects that may be unpleasant or  Patient needs to be taught to empty the even dangerous. bladder before taking the drug.  They can occur for many reasons, including the following:  The drug may have other effects on V. DRUG ALLERGY the body besides the therapeutic  Occurs when the body forms antibodies to a effect. particular drug, causing an immune response  The patient may be sensitive to the when the person is re-exposed to the drug. drug being given.  Drug allergies fall into four main classifications:  The drug’s action on the body may  Anaphylactic reactions cause other responses that are  Cytotoxic reactions undesirable or unpleasant.  Serum sickness  The patient may be taking too much  Delayed reactions or too little of the drug, leading to adverse effects. VI. DRUG-INDUCED TISSUE AND  Adverse drug effects can be one of several types: ORGAN DAMAGE  Primary actions  Drugs can act directly or indirectly to cause many types of adverse effects in various tissues,  extensions of the desired effect structures, and organs.  Secondary actions  effects that the drug causes VII. DERMATOLOGICAL REACTIONS: in the body that are not  RASHES, HIVES related to the therapeutic  Although many patients will report effect. that they are allergic to a drug  Hypersensitivity reactions because they develop a skin rash  individual reactions that may when taking the drug, it is important to be caused by increased determine whether a rash is a sensitivity to the drug’s commonly associated adverse effect therapeutic or adverse of the drug. effects. ASSESSMENT: III. SAFE MEDICATION Severe reactions may include:  Exfoliative dermatitis ADMINISTRATION  which is characterized by rash and scaling  Before administering any drug to a patient, it is  Fever important to review the contraindications and  Enlarged lymph nodes  Enlarged liver cautions associated with that drug, as well as  and the potentially fatal erythema multiforme the anticipated adverse effects of the drug. exudativum (Stevens–Johnson syndrome),  When teaching the patient about a drug, you  which is characterized by dark red papules should list the adverse effects that should be appearing on the extremities with no pain anticipated, along with the appropriate or itching actions that the patient can take to alleviate  often in rings or diskshaped patches. any discomfort associated with these effects. - NICOLE CADENCE CARAAN - INTERVENTIONS:  In mild cases, or when the benefit of the drug VIII. SUPERINFECTIONS outweighs the discomfort of the skin lesion,  Several kinds of drugs (especially antibiotics)  provide frequent skin care destroy the normal flora, leading to the  instruct the patient to avoid rubbing, development of superinfections, or infections wearing tight or rough clothing, and using caused by organisms that are usually harsh soaps or perfumed lotions controlled by the normal flora.  administer antihistamines, as appropriate.  In severe cases, discontinue the drug and notify the ASSESSMENT: prescriber and/or primary caregiver. Symptoms can include:  Be aware that, in addition to these  fever interventions,  diarrhea topical corticosteroids,  black or hairy tongue antihistamines, and  inflamed and swollen tongue (glossitis) emollients  mucous membrane lesions are frequently used.  vaginal discharge with or without itching. INTERVENTIONS:  Provide supportive measures  frequent mouth care,  skin care,  access to bathroom  facilities,  small and frequent meals  Administer antifungal therapy as appropriate. In severe cases, discontinue the drug responsible for the superinfection.  STOMATITIS IX. BLOOD DYSCRASIA  This is a bone marrow suppression caused by  An inflammation of the mucous drug effects. membranes, can occur because of a  This occurs when drugs that can cause cell direct toxic reaction to the drug or death (e.g., antineoplastics, antibiotics) are because the drug deposits in the end used. capillaries in the mucous membranes, leading to inflammation. ASSESSMENT: ASSESSMENT: Symptoms include:  Symptoms can include:  Fever  swollen gums  Chills  inflamed gums (gingivitis)  Sore throat  swollen and red tongue (glossitis)  Weakness  Other symptoms include:  Back pain  difficulty swallowing  Dark urine  bad breath  Decreased hematocrit (anemia)  pain in the mouth and throat  Low platelet count (thrombocytopenia)  Low white blood cell count (leukopenia) INTERVENTIONS:  A reduction of all cellular elements of the complete  Provide frequent mouth care with a non-irritating blood count (pancytopenia) solution.  Offer nutrition evaluation and development of a INTERVENTIONS: tolerated diet,  Monitor blood counts.  which usually involves frequent, small  Provide supportive measures meals.  Rest  If necessary, arrange for a dental consultation.  Protection from exposure to infections  Note that antifungal agents and/or local  Protection from injury anesthetics are sometimes used.  Avoidance of activities that might result in injury or bleeding  In severe cases, discontinue the drug or stop administration until the bone marrow recovers to a safe level. - NICOLE CADENCE CARAAN - X. LIVER INJURY XII. POISONING  Oral drugs are absorbed and passed directly  occurs when an overdose of a drug damages into the liver in the first-pass effect. multiple body systems, leading to the potential  This exposes the liver cells to the full impact of for fatal reactions. the drug before it is broken down for circulation throughout the body. ASSESSMENT: parameters vary with the particular drug ASSESSMENT: Symptoms may include: TREATMENT:  fever Also varies, depending on the drug.  malaise  Emergency and life support measures often are  nausea needed in severe cases.  vomiting  jaundice XIII. ALTERATIONS IN GLUCOSE  change in color of urine or stools  abdominal pain or colic METABOLISM:  elevated liver enzymes (e.g., aspartate  HYPOGLYCEMIA aminotransferase [AST], alanine aminotransferase  Some drugs affect metabolism and [ALT]) the use of glucose, causing a low  alterations in bilirubin levels  changes in clotting factors (e.g., partial serum blood glucose concentration, thromboplastin time) or hypoglycemia.  Glipizide (Glucotrol) and glyburide INTERVENTIONS: (DiaBeta) are antidiabetic agents that  Discontinue the drug and notify the prescriber have the desired action of lowering and/or primary caregiver. the blood glucose level but can lower  Offer supportive measures such as: blood glucose too far, causing  small, frequent meals hypoglycemia.  skin care  a cool environment ASSESSMENT:  rest periods  Symptoms may include:  Fatigue XI. RENAL INJURY  Drowsiness  The glomerulus in the kidney has a very small  Hunger capillary network that filters the blood into the  Anxiety renal tubule.  Headache  cold, clammy skin  Gentamicin (Garamycin), a potent antibiotic, is  shaking and lack of coordination frequently associated with renal toxicity. (tremulousness)  increased heart rate ASSESSMENT:  increased blood pressure  Elevated blood urea nitrogen (BUN)  numbness and tingling of the mouth,  Elevated creatinine concentration tongue, and/or lips  Decreased hematocrit  Confusion  Electrolyte imbalances  rapid and shallow respirations  Fatigue  In severe cases, seizures and/or coma may occur.  Malaise  Edema INTERVENTIONS:  Irritability  Restore glucose (orally), if possible, or intravenously  Skin rash may be seen (IV).  Provide supportive measures INTERVENTIONS:  skin care  Notify the prescriber and/or primary caregiver and  environmental control of light and discontinue the drug as needed. temperature  Offer supportive measures  rest  positioning, diet and fluid restrictions,  Institute safety measures to prevent injury or falls.  skin care,  Monitor blood glucose levels to help  electrolyte therapy, stabilize the situation.  rest periods,  Offer reassurance to help the patient cope with the  a controlled environment. experience. In severe cases, be aware that dialysis may be required for survival - NICOLE CADENCE CARAAN -  HYPERGLYCEMIA  In severe cases:  paralytic ileus  Some drugs stimulate the breakdown  absent bowel sounds, of glycogen or alter metabolism in  abdominal distention, and such a way as to cause high serum  acute abdomen glucose levels, or hyperglycemia. may occur. ASSESSMENT: INTERVENTIONS:  Fatigue  Replace serum potassium and carefully monitor  Increased urination (polyuria) serum levels and patient response;  Increased thirst (polydipsia)  achieving the desired level can take time,  Deep respirations (Kussmaul respirations) and the patient may experience high  Restlessness potassium levels in the process.  increased hunger (polyphagia)  Provide supportive therapy  Nausea  safety precautions to prevent injury or falls  hot or flushed skin  reorientation of the patient  Fruity odor to breath  comfort measures for pain and discomfort may be observed.  Cardiac monitoring may be needed to evaluate the effect of the fluctuating potassium levels on heart INTERVENTIONS: rhythm.  Administer insulin therapy to decrease blood glucose as appropriate, while carefully monitoring glucose levels.  HYPERKALEMIA  Provide support to help the patient deal with signs  Some drugs that affect the kidney, and symptoms such as the potassium sparing  provide access to bathroom facilities, diuretics, can lead to potassium  control the temperature of the room, retention and a resultant increase in  decrease stimulation while the patient is in serum potassium levels (hyperkalemia). crisis,  Other drugs that cause cell death or  offer reassurance, injury, such as many antineoplastic  provide mouth care agents, also can cause the cells to  the patient will experience dry release potassium, leading to mouth and bad breath with the ensuing acidosis, hyperkalemia.  mouth care will help to make this ASSESSMENT: more tolerable Symptoms include a:  serum potassium level higher than 5.0 mEq/L,  weakness, XIV. ELECTROLYTE IMBALANCES:  muscle cramps,  HYPOKALEMIA  diarrhea,  Some drugs affecting the kidney can  numbness and tingling,  slow heart rate, cause low serum potassium levels  low blood pressure, (hypokalemia) by altering the renal  decreased urine output, and exchange system.  difficulty breathing  Potassium is essential for the normal functioning of nerves and muscles. INTERVENTIONS:  Use of sodium polystyrene sulfonate. ASSESSMENT:  Careful monitoring is important until the patient’s  Symptoms include: potassium levels are stable.  a serum potassium concentration ([K])  Institute safety measures to prevent injury or falls. lower than 3.5 mEq/L  Monitor for cardiac irregularities because potassium  Weakness is an important electrolyte in the action potential,  numbness and tingling in the extremities which is needed for cell membrane stability.  muscle cramps  When potassium levels are too high, the  Nausea cells of the heart become very irritable  Vomiting and rhythm disturbances can occur.  Diarrhea  Be prepared for a possible  decreased bowel sounds cardiac emergency.  irregular pulse In severe cases, be aware that dialysis may be needed.  weak pulse  orthostatic hypotension  and disorientation. - NICOLE CADENCE CARAAN - XV. SENSORY EFFECTS: XVI. NEUROLOGIC EFFECTS:  OCULAR DAMAGE  CENTRAL NERVOUS SYSTEM EFFECTS  The blood vessels in the retina are very  Although the brain is fairly well tiny and are called “end arteries,” that protected from many drug effects by is, they stop and do not interconnect the blood–brain barrier, some drugs with other arteries feeding the same do affect neurological functioning, cells. either directly or by altering electrolyte  Some drugs are deposited into these or glucose levels. tiny arteries, causing inflammation and  Beta-blockers, which are used to treat tissue damage. hypertension, angina, and many other conditions, can cause feelings of ASSESSMENT: anxiety, insomnia, and nightmares.  Blurring of vision,  color vision changes, ASSESSMENT:  corneal damage, and Symptoms may include:  blindness  confusion, may be noted.  delirium,  insomnia, INTERVENTIONS:  drowsiness,  Monitor the patient’s vision carefully when the  hyperreflexia or hyporeflexia, patient is receiving known oculotoxic drugs.  bizarre dreams,  Consult with the prescriber and/or primary caregiver  hallucinations, and discontinue the drug as appropriate.  numbness,  Provide supportive measures, especially if vision loss  tingling, and is not reversible.  paresthesias  Monitor lighting and exposure to sunlight. INTERVENTIONS:  AUDITORY DAMAGE  Provide safety measures to prevent injury.  Tiny vessels and nerves in the eighth  Caution the patient to avoid dangerous situations such as driving a car or operating dangerous cranial nerve are easily irritated and machinery. damaged by certain drugs.  Orient the patient and provide support.  The macrolide antibiotics can  Consult with the prescriber to decrease drug dose or cause severe auditory nerve discontinue the drug. damage.  Aspirin, one of  ATROPINE-LIKE (ANTICHOLINERGIC) the most commonly used EFFECTS drugs, is often  Some drugs block the effects of the linked to parasympathetic nervous system by auditory ringing directly or indirectly blocking and eighth cholinergic receptors. cranial nerve  Atropine, a drug used preoperatively effects. to dry up secretions and any other indications, is the prototype ASSESSMENT: anticholinergic drug.  Dizziness,  Many cold remedies and  ringing in the ears (tinnitus), antihistamines also cause  loss of balance, and anticholinergic effects.  loss of hearing may be assessed. ASSESSMENT:  Dry mouth, INTERVENTIONS:  altered taste perception,  Monitor the patient’s perceptual losses or changes.  dysphagia,  Provide protective measures to prevent falling or  heartburn, injury.  constipation,  Consult with the prescriber to decrease dose or  bloating, discontinue the drug.  paralytic ileus,  Provide supportive measures to cope with drug  urinary hesitancy and retention, effects.  impotence,  blurred vision,  cycloplegia,  photophobia,  headache,  mental confusion, - NICOLE CADENCE CARAAN -  nasal congestion, ASSESSMENT:  palpitations,  Extrapyramidal symptoms, including:  decreased sweating,  slowed reflexes,  and dry skin  rigidity, may be noted.  involuntary movements;  hyperthermia; and INTERVENTIONS:  autonomic disturbances, such as:  Provide sugarless lozenges and mouth care to help  hypertension, mouth dryness.  fast heart rate, and  Arrange for bowel program as appropriate.  fever,  Have the patient void before taking the may be noted drug, to aid voiding.  Provide safety measures if vision changes occur. INTERVENTIONS:  Arrange for medication for headache and nasal  Discontinue the drug, if necessary. congestion as appropriate.  Know that treatment with anticholinergics or  Advise the patient to avoid hot environments and to antiparkinson drugs may be required. take protective measures to prevent falling and to  Provide supportive care to lower the body prevent dehydration, which may be caused by temperature. exposure to heat owing to decreased sweating.  Institute safety precautions as needed.  PARKINSON-LIKE SYNDROME XVII. TERATOGENICITY  Drugs that directly or indirectly affect  Many drugs that reach the developing fetus or dopamine levels in the brain can embryo can cause death or congenital cause a syndrome that resembles defects, which can include skeletal and limb Parkinson’s disease. abnormalities, central nervous system  Many of the antipsychotic and alterations, heart defects, and the like. neuroleptic drugs can cause this  The exact effects of a drug on the fetus may effect. not be known.  In most cases, the effects go  In some cases, a predictable syndrome occurs away when the drug is when a drug is given to a pregnant woman. withdrawn.  In any situation, inform any pregnant woman who requires drug therapy about the possible ASSESSMENT: effects on the baby.  Lack of activity (akinesia)  Before a drug is administered to a pregnant  muscular tremors, patient, the actual benefits. should be  drooling,  changes in gait, weighed against the potential risks.  rigidity,  All pregnant women should be  extreme restlessness or “jitters” (akathisia), or advised not to self-medicate during  spasms (dyskinesia) the pregnancy. may be observed  Emotional and physical support is needed to assist the woman in dealing with the possibility INTERVENTIONS: of fetal death or birth defects.  Discontinue the drug, if necessary.  Know that treatment with anticholinergics or anti- parkinson drugs may be recommended if the XVIII.THE NURSING PROCESS IN DRUG benefit of the drug outweighs the discomfort of its adverse effects. THERAPY AND PATIENT SAFETY  Provide small, frequent meals if swallowing becomes difficult. NURSING PROCESS  Provide safety measures if ambulation becomes a  Nurses use the nursing process (a problem. decision-making, problem-solving process) to provide efficient and  NEUROLEPTIC MALIGNANT SYNDROME effective care  General anesthetics and other drugs that have direct central nervous system effects can cause neuroleptic malignant syndrome, a generalized syndrome that includes high fever. - NICOLE CADENCE CARAAN - KEY ELEMENTS  EVALUATION  ASSESSMENT  Evaluation is part of the continuing  Assessment (gathering information) is process of patient care that leads to the first step of the nursing process. changes in assessment, diagnosis, and  This involves systematic, intervention. organized collection of data  The patient is continually evaluated for: about the patient.  therapeutic response,  Each nurse develops a unique  the occurrence of adverse approach to the organization of the drug effects, and the assessment, an approach that is  occurrence of drug–drug, functional and useful in the clinical drug–food, drug–alternative setting and that makes sense to that therapy, or drug–laboratory nurse and in the particular ` clinical test interactions. situation. XIX. PREVENTION OF MEDICATION  NURSING DIAGNOSIS  A nursing diagnosis is simply a ERRORS statement of the patient’s status from  Nurses should be keen in catching for errors a nursing perspective.  the wrong drug,  The nurse analyzes the information  the wrong patient, gathered duri