Assessment of Core Patient Variables – health status

Assessment of Core Patient Variables – health status

1. concurrent medical conditions may increase the risk for adverse effects from drug therapy

2. a patient's chronic health condition may also necessitate drug therapy that may interact with other drug therapy or promote adverse effects

Assessment of Core Patient Variables – life span & gender

1. young children and older adults have livers & kidneys that do not function as well as those of young adults

2. older adults are more likely to be receiving polypharmacy for mulitple chronic illnesses and thus are more likely to experience drug interactions

3. adverse effects from drug therapy taken by a pregnant woman may affect the unborn child

Assessment of Core Patient Variables – lifestyle, diet, and habits

1. use of tobacco, alcohol, caffeine, street drugs, or over-the-counter herbs and botanicals may influence the effects of drug therapy

2. the nurse should remember to ask patients about diet and other habits when performing a drug history or when providing patient education on prescribed drug therapy

Assessment of Core Patient Variables – environment

1. some antibiotics can cause the adverse effect of photosensitivity

2. drugs (such as anticholinergics, belladonna alkaloids) reduce the body's tolerance to heat or inhibit the body's ability to reduce temperature by perspiration

Assessment of Core Patient Variables – environment can also play a role in the early detection of adverse effects

1. receiving drug therapy under close supervision (some only given in hospital setting)

2. receiving drug therapy in a community setting (some home healthcare nurses can give chemotherapy)

Assessment of Core Patient Variables – culture and inherited traits

1. researchers are beginning to study responses to drug therapy that are genetically determined in various ethnic and racial populations

2. these responses may place the patient at greater risk for adverse effects or drug interactions than the rest of the global population

Planning & Intervention – Maximizing Therapeutic Effects

1. when drug interactions are intentional and desirable, the nurse needs to give the drugs at the prescribed time intervals

2. when drug interactions are not desired, but both drugs are needed for therapy, the doses must be administered at different times to promote the therapeutic effect of each drug

Minimizing Adverse Effects

1. to help protect the pt from serious adverse effects & drug interactions, nurse must obtain health history

2. throughout therapy, the patient should be monitored for signs and symptoms of interactions and adverse effects and for alterations in health status that increase the risk for adverse effects

Providing Patient and Family Education – before & throughout drug therapy, the nurse needs to inform pt and family about adverse effects & drug interactions

Ongoing Assessment and Evaluation

1. during drug therapy, the nurse continues to monitor for adverse effects and drug interactions, including allergic responses

2. the nurse should also consider the possibility of a drug interaction each time a new drug is added to the treatment plan

3. if none of these effects occurs and the therapeutic effect has been achieved, drug therapy is evaluated as successful

Hepatoxicity (damage to the liver)

Hepatoxicity (damage to the liver) manifestations include:

1. hepatitis, jaundice, elevated liver enzyme levels, and fatty infiltration of the liver

2. hepatic anatomy and function both contribute to the high susceptibility of the liver to toxicants

Nephrotoxicity (damage to kidneys) signs & symptoms:

1. decreased urinary output

2. elevated blood urea nitrogen

3. increased serum creatinine

4. electrolyte imbalances

5. renal function contributes to development of nephrotoxicity

Ototoxicity (damage to 8^th cranial nerve) signs & symptoms:

1. tinnitus

2. sensorineural hearing loss

3. light-headedness, vertigo, a spinning sensation from a seated position, nausea and vomiting

Drug Interactions

1. drug interactions occur when one drug (drug "A")is affected in some way by

   another drug (drug "B"), a food, or some other substance taken concurrently

2. drug interactions may be beneficial or adverse, intended or unintended

3. drug interactions may take place in any phase of pharmacokinetics, absorption, distribution, metabolism, or excretion

Drug Interactions affecting absorption

1. drug absorption is often decreased because of drug interactions

2. if a drug binds with another substance in the GI tract, less of the drug is available to be absorbed

3. drug absorption may be increased as a result of a drug interaction or the presence of food in the GI tract

4. a less acidic environment decreases ionization of drugs that are basic, which promotes absorption of these drugs

Drug Interactions affecting metabolism

1. grapefruit juice is also known to inhibit CYP3A4

2. some herbs and botanicals may also affect the CYP3A4 enzyme, such as St John's Wort

3. alcohol & nicotine alter the metabolism of some drugs

Drug Interactions affecting Pharamacodynamics

1. drugs that act in different ways or at different receptors can interact in several ways

2. they may create an additive effect, a synergistic effect, a potentiated effect, or antagonistic effect

Additive Effect

1. Drug A + Drug B = 2 (1+1=2)

2. beneficial: (codeine combined with tylenol provides better pain control than either alone

3. harmful: alcohol taken with salicylates (aspirin) increases risk for GI bleeding; morphine taken with alcohol = CNS depression, can be fatal

Potentiated Effect

1. ½ (drug A) + (drug B) = 2

2. beneficial – antiemetic drug hydroxyzine combined with morphine increases the pain-relieving ability of the morphine without increasing the dose of the morphine

Antagonistic Effect

1. Drug A + Drug B – 0 (1+1=0)

2. beneficial – heparin and protamine sulfate (a heparin antagonist) form an ionic bond that lacks any anticoagulant activity. *antidote

Drug Incompatibilities (chemical incompatibilities between drugs change both the drug's structure and its pharmacologic properties)

1. beneficial – heparin & protamine sulfate

2. harmful – combining multivitamins & antibiotics in the same IV solution changes the solution's pH and inactivates the antibiotic (precipitates out)

Drug Incompatibilities (physical incompatibilities occur when two drugs are mixed together)

harmful

1. Phenytoin (dilantin) and a diluent containing dextrose produce a cloudy white precipitate (should only mix dilantin with normal saline)

2. this kind of reaction usually interferes with pharmacologic activity of one or both drugs

Implications for Nursing Management – health team must ensure a beneficial outcome by:

1. maximizing therapeutic effects

2. minimizing adverse effects & drug interactions

3. providing appropriate drug education for the patient & family

Drug Dosage and Blood Concentration – therapeutic range

Drug Dosage and Blood Concentration – therapeutic range

1. the goal of drug dosing is to give a dose that places the drug concentration above the MEC but below the level at which adverse effects occur

2. the drug blood level is only one piece of data that must be considered when evaluating the patient's response to drug therapy

A Nurse's Role in Monitoring Drug Blood Levels

1. notify the physician or nurse practitioner if the level indicates that the patient is not in the therapeutic range or is greatly above the therapeutic range

2. if a patient appears to be experiencing adverse effects

3. if is important to note the exact time the last dose of the drug was administered on the drug blood level specimen slip

Adverse Effects – undesirable effect other than the intended therapeutic effect

can check "trough" - check blood 30 minutes prior to medication dose and then check "peak" after dose is given

Drug interaction: occurs when two drugs or a drug and another element (such as food) have an effect on each other

*Minimize adverse effects & maximize positive effects, plan for pt education

Adverse Effects – Nurses need to understand adverse effects and drug interactions and use this knowledge in their management of drug therapy.

Two types of adverse effects:

1. mild adverse effects, such as nausea, are bothersome perhaps only to the pt

2. serious adverse effects, such as liver failure, are life threatening

Determining Adverse Effects

1. It is important for nurses and other health care professionals to be alert for adverse effects from drug therapy.

2. Adverse effects may be mistaken for changes associated with aging or disease pathology.

Adverse Effects – Not predictable or dose related – Allergic Response

1. an allergic response is an immune system response

2. symptoms of allergy due to release of histamine

3. redness, itching, swelling, rash, hives

4. most serious allergic response is called anaphylaxis (breathing shuts down, death can follow)

Adverse Effects – Not predictable or dose related – Idiosyncratic Response

1. related to the individual rather than dose-related

2. idiosyncratic responses (sometimes called paradoxical effects) to a drug are unusual and in fact may be the opposite of what is anticipated

Adverse Effects – toxicities

1. specific patterns or groups of symptoms related to drug therapy that carry risk for permanent damage or death are called toxicities

2. the organ or system that is affected is used to name the toxicity, ie. neurotoxicity, nephrotoxicity, cardiotoxicity, hepatotoxicity, ototoxicity, and immunotoxicity

Neurotoxicity – sometimes referred to as CNS toxicity, it is a drug's ability to harm or poison a nerve cell or nerve tissue (alkaloids for chemotherapy, such as vincristine can cause irreversible damage and can affect pt's ability to lift feet)

1. injury to the CNS is largely irreversible because the highly differentiated neurons of the brain cannot divide and regenerate

2. immature nervous systems (ie. fetal and neonate nervous systems) can easily be damaged by drugs that produce neurotoxicity

Pharmacodynamics – drug-receptor interactions

Pharmacodynamics – drug-receptor interactions

1. most drugs create their effects in the body by attaching to special sites called receptors on cells

2. when drug molecules attach to a receptor, they can stimulate the cell to act and are called agonists

3. by attaching to a receptor, drug molecules can prevent something else from attaching and causing an effect and are described as antagonists or blockers

   *Morphine competes with Narcan. When Morphine is locked on cells, Narcan can't lock on. narcotic antagonists. This is important for renal patients who can't excrete enough Morphine fast enough

4. a drug may latch onto a site to prevent a hormone or a neurotransmitter from attaching to the cell and turning on a function

5. if the drug is on, the other chemical cannot also be on the receptor

6. because there is competition for the receptor sites, the chemical that is present in the largest amount, either the drug or the internal regulator, is the most likely to be near an open receptor and attach to the receptor site

7. most drugs that are antagonists are competitive; only a very few are not

Pharmacodynamics – nonreceptor responses

Although most drug effects are related to drug-receptor responses, some drugs exert their effect by reacting physically or chemically with other molecules in the body. for example:

1. antacids react with HCL & raise pH (make stomach more alkaline)

2. heparin – anticoagulant physically thinning blood

Variables that Influence the Dose of a Drug – potency and efficacy

1. a certain level of a drug must be present in the body to produce an effect called the Minimum Effective Concentration (MEC)

2. the amount of a drug that must be given in order to produce a particular response – its relative pharmacologic activity is called the potency of a drug

3. two drugs may have different potencies but the same efficacy

4. rarely is potency the most important consideration when selecting a drug

Variables that Influence the Dose of a Drug – selecting a drug may depend on:

1. pill size

2. cost of each drug

3. the adverse effects from each one

4. route of administration

If drugs have similar potencies, but different efficacies, the drug that has better efficacy is usually preferred because this drug does a better job of achieving the desired therapeutic effect

Pharmacokinetics Distribution (Blood-Brain Barrier)

Pharmacokinetics Distribution (Blood-Brain Barrier)

1. the blood-brain barrier keeps toxins & poisons from reaching the brain.

2. only drug molecules that are lipophilic (able to cross) or that have a transport system

   can penetrate the barrier

Pharmacokinetics Distribution (placental barrier)

1. placental barrier separates maternal circulation from fetal circulation

2. in order to pass through placenta, drug must be lipophilic, not ionized, & not protein bound

Pharmacokinetics – Metabolism of drugs

1. occurs primarily in the liver

2. some metabolism occurs in other tissues, ie. gastrointestinal (GI) tract, lungs, kidney, & skin

3. when drugs are metabolized, they are changed from their original form to a new form

   sometimes referred to as "biotransformation"

   Pharmacokinetics – Metabolism Rates

   1. metabolism occurs at different rates for different drugs

   2. the percentage of drug that is metabolized each time the drug circulates or passes through the

   liver is the same, but the total number of drug molecules that are metabolized will be different

Pharmacokinetics – Metabolism first-pass effect (oral)

1. highly metabolized drugs may lose their therapeutic effectiveness quickly during their first pass through the liver (following oral administration), before they reach general circuation

2. This loss of effectiveness is called first-pass effectively

Pharmacokinetics: Excretion – the process of removing a drug or its metabolites from the body

routes for drug excretion:

1. urine (most common)

2. bile in the GI tract

3. expired air from lungs

4. breast milk

5. sweat from the skin (therapeutically not important)

6. saliva (therapeutically not important)

Pharmacokinetics: Excretion – three processes involved in renal excretion

1. glomerular filtration

2. passive tubular reabsorption

3. active tubular secretions

Pharmacokinetics: Excretion – half-life

1. the amount of time that is required to remove half (50%) of the blood concentration of a drug is called half-life

2. drugs have various half-lives measured in minutes or even days

3. in one half-life, a set percentage of the drug molecules present in the blood will be eliminated, not an absolute set number of drug molecules

Pharmacokinetics: Excretion – steady state

1. the full pharmacotherapeutic response of a particular drug dose is measured when the drug has achieved steady state

2. steady state is not based on drug dose or frequency of drug administration

Pharmacokinetics: Excretion – clearance (rate at which drug molecules disappear from circulatory system

major modes of clearance include:

1. renal excretion (kidney)

2. hepatic metabolism (liver)

gender of patient can alter the clearance of some drugs (affected by hormones, adipose in females etc)

Pharmacodynamics: the biological, chemical, and physiologic actions of a particular drug within the body and the study of how those actions occur

Pharmacotherapeutics – Drug label

Pharmacotherapeutics – Drug label (approval of a drug for a particular indication)

1. findings from clinical drug trials are submitted to FDA which oversees new drug approval in U.S.

2. information about a drug approved for a particular indication or indications is included when labeling the drug and in printed material about the drug

Pharmacotherapeutics – modification of a drug label

1. the official drug label is modified only if the drug company goes back to the FDA with additional information and requests that a new pharmacotherapeutic indication be added

2. after an official review, the FDA may decide to alter the drug label

Nonlabeled (off-label) Use Based on:

1. findings of additional research studies that are performed and reported in the professional literature

2. case reports published in the literature (nurses should not be over concerned about off-label use

Pharmacokinetics: movement of the drug inside the body and the resulting processes that occur

There are four phases:

1. absorption

2. distribution

3. metabolism

4. exretion

Pharmacokinetics – to move throughout body, drug must cross membranes in one of 3 ways:

1. first, drug molecules that are small can pass between the spaces or channels between the molecules in the membrane

2. second, drugs pass through membrane with help of a transport system (with or without energy)

3. third, drugs which are lipophilic can penetrate the membrane directly

Pharmacokinetics – factors affecting rate & completeness of absorption

1. route of administration

2. rate of dissolution

3. surface area

4. blood flow

5. lipid solubility

6. pH differences between the site of administration and the plasma

7. physiologic condition of the patient

Pharmacokinetics – Distribution depends on:

1. blood flow to tissues

2. the drug's ability to leave the blood

3. the drug's ability to enter cells

4. in healthy individuals, all tissues are well perfused, thus the drug molecules can easily be distributed throughout the body

5. scar tissue is avascular, and adipose (fat) tissue has a poor blood supply

6. abscesses and solid tumors are also avascular

Patient Education as a Safeguard in Drug Therapy

Patient Education as a Safeguard in Drug Therapy – enhancing patient education

1. identifying patient learning needs

2. achieving accurate teaching focus

3. communicating accurate content

4. evaluating & documenting educational outcomes (pt can demonstrate knowledge learned)

5. discussing contradictory information available on the internet

The importance of nursing management of drug therapy

1. continuous growth of importance of pharmacotherapy in nursing practice

2. legal responsibility of nurses for the drugs they administer & for safe drug administration

Aschenbrenner

Pharmacotherapeutics: achievement of the desired therapeutic goal from drug therapy

1. It is the clinical purpose or indication for giving a drug.

2. used to treat or manage a chronic condition (ie. aspirin for arthritis pain)

3. induce a cure (antibiotic for an infection)

4. prevent a problem (fluoride for teeth)

Legislation Regarding Controlled Substances

Legislation Regarding Controlled Substances

1. designed to address problem of drug abuse

2. places controls on prescribing drug dispensing & storing of drugs

3. established methods that allow drugs to be moved from one schedule category to another

4. nursing management involves documentation of administration of a narcotic on a narcotic log sheet

Legislation Regarding Drug Distribution

1. prescribed drugs are identified by legend

2. controlled substances must display warning label (caution in storage, use, don't drive)

Effect of Legal & Institutional Controls on Nursing Management of Drug Therapy

A nurse needs to:

1. be responsible or drug security

2. be responsible for safely administering drug

Legislation for Drug Safety & Efficacy

Legislation for Drug Safety & Efficacy

1. Pure Food and Drug Acts (1906) to protect from unsafe meat processing

   A. USP (U.S. Pharmacopeia) monitors drug:

   a. strength

   b. quality

   c. purity in medicine preparation

2. National Formulary (NF) sets standards for drug quality

3. Federal Food, Drug, and Cosmetics Act of 1938 (FFDCA – later became FDA) established that drugs must be tested & labeled accurately

4. Kefauver-Harris Amendment (1962) came from the tragedy of deformed Thalidimide babies – manufacturer must prove safety, efficacy, & adverse reactions & list in literature

Procedure for Drug Development and Approval – new drug molecule is subjected to:

1. preclinical trials to determine basic safety, efficacy, 3 ½ yrs.testing, of every 1000 compounds, only one make it to human test

2. clinical trials

   A. volunteers

   B. vary dosages

   C. tested on 1000 to 3000 subjects

   D. surveillance of medication (Medwatch – practitioners' reporting process)

Approval Process

1. only 10% of drugs win regulatory approval

2. long, complex, and expensive process

3. average estimation = 12 yrs & $350 million for new drug to be approved

Drug Classifications –Pharmacologic Groups or Families

Drug Classifications –Pharmacologic Groups or Families

1. chemical classification (ie prostaglandin synthetase inhibitor)

2. physiologic classification (effect) N.S.A.I.D.

3. therapeutic classification – clinical indication, why you use it (pain med., antipyretic, anti-inflammatory)

Sources of Drug Information – nurses need:

1. reliable, up to date drug reference information

2. awareness of reliable sources and the specific type of information provided in them

3. information on safe drug administration and new developments

Governmental Safeguards in drug development, manufacture, & distribution in the U.S.

1. standards for drug purity & content

2. legislation for drug safety & efficacy (effectiveness)

3. procedure for drug development & approval

4. legislation to promote truth in advertising

5. legislation regarding controlled substances

6. legislation regarding drug distribution

7. nongovernmental institutional controls

Pharmaceuticals: Development, Safeguards, and Delivery

Pharmaceuticals: Development, Safeguards, and Delivery

What is a drug?

1. any chemical that can affect living processes

2. used to treat a variety of health problems

Historical Perspectives of drug development

1. Up to 19^th century pharmacology knowledge was derived from simple observation & practical experience (herbologists & astrologists)

2. during the 19^th century pharmacology evolved into a highly specialized science, and the branch of pharmaceutical chemistry developed

Sources of Drugs

1. plants – (willow- aspirin, St. Johnswort, digitalis- foxglove)

2. animals – insulin, birth control pills (mare urine0

3. synthetic chemicals

4. genetically engineered chemicals

Drug Nomenclature – all drugs are knows by:

1. chemical name – atomic & molecular structure (2-(4-Isobutyl-phenyl)-propionic acid

2. generic name (nonproprietary name) official name in U.S., know for pt safety, ie. Ibuprofen

3. trade name (proprietary name) ie. Advil, Motrin

Implications for Nurses – responsibility for accurately:

1. transcribing drug orders – go to original order, clarify with physician

2. administering the drug correctly

3. documenting the patient's response (5 pt rights include these0

4. ordering drugs by generic names

5. checking the drug name at least 3 times – before, during, & after obtaining the drug

Principles of min adverse effects of a drug

Principles of min adverse effects of a drug

1. verify that the patient is not allergic to the drug

2. check the method of administration is consistent with standard safety protocols

3. report evidence of adverse effects to the prescriber

Intervention – performing the plan

1. administer the medication

2. provide patient drug education

   Intervention – core drug knowledge

basic drug therapy education should include:

1. name of the drug

2. reason drug was prescribed

3. important adverse effects that may occur (ie. narcotic can suppress respiration – monitor breathing)

Intervention – core patient variables

patient education should cover the following:

1. measure the patient's progress (ie blood pressure)

2. reassess to identify the barriers to success

3. identify the reason behind any treatment failure

4. take steps to achieve desired results effectively

Clinical Pathways – tools to communicate standardized, interdisciplinary plan of care for pts.

1. specify the responsibilities, actions, and time frame required of each discipline

2. provide a standard of care for all patients with the same diagnosis

3. are not substitutes for nursing assessment and judgment

Principles of maximizing therapeutic effects of a drug

Sources of data – physical examination

1. focuses on the core patient variables: health status, life span, & gender

2. can be done by general observation

3. must obtain baseline data

4. must analyze data in terms of the specific current & proposed drugs

Sources of data – medical records

1. provide information about the patient's health status, lifestyle, diet, habits, & environment

2. other important areas: laboratory & diagnostic test results (ie. glucose results)

3. past medical records may be used to verify the patient's drug history

Planning

1. maximizing therapeutic effect

2. minimizing adverse effect

Principles of maximizing therapeutic effects of a drug

1. administer the drug in a manner:

   A. to promote its absorption

   B. at the appropriate time to maintain blood levels of the drug (ie give diuretic a.m. )

   (K+) potassium and sodium (Na+)

2. monitor laboratory values when appropriate - (K+) potassium and sodium (Na+) with diuretic

Nurse's Role in Drug Therapy

Pharmacology

Nurse's Role in Drug Therapy

Components of Core Drug Knowledge are:

1. pharmacotherapeutics -

2. pharmacokinetics – effect of body on drug

3. pharmacodynamics – process by which drugs alter cell physiology & affect body

4. contraindications & precautions – why not to give a drug

5. adverse effects

6. drug interactions

Nurse's Role in Drug Therapy

Components of core patient variables are:

1. health status (ie. kidney problems)

2. life span, gender

3. lifestyle, diet, and habits

4. environment

5. culture & inherited traits

Managing Drug Therapy Through the Nursing Process:

Assessment

1. assessment of core drug knowledge

   using a prototype drug (representative of a class of drugs) in Aschenbrenner book, red letter "P"

2. assessment of core patient variables

Core Patient Variables

sources of data

1. patient interview & history

2. physical examination

3. medical record

Sources of data

1. patient interview & history

   A. open-ended questions

   B. close-ended questions

2. questions are asked with regard to:

   A. Health status - "How has this affected you?"

   B. life span & gender

   C. lifestyle, diet, and habits

   D. environment

   E. culture & inherited traits