Nursing 3703 pharmacology in nursing
This presentation is the property of its rightful owner.
Sponsored Links
1 / 71

Nursing 3703 Pharmacology in Nursing PowerPoint PPT Presentation


  • 261 Views
  • Uploaded on
  • Presentation posted in: General

Nursing 3703 Pharmacology in Nursing. Introduction to Drug Therapy Linda Self. Grouping of Drugs. Names may reflect the conditions for which they are used (e.g. antidepressants) May reflect their chemical characteristics (benzodiazepines)

Download Presentation

Nursing 3703 Pharmacology in Nursing

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Nursing 3703 pharmacology in nursing

Nursing 3703Pharmacology in Nursing

Introduction to Drug Therapy

Linda Self


Grouping of drugs

Grouping of Drugs

  • Names may reflect the conditions for which they are used (e.g. antidepressants)

  • May reflect their chemical characteristics (benzodiazepines)

  • May reflect the effects on body systems (central nervous system depressants)


Prototype drugs

Prototype Drugs

  • Individual drugs that represent groups of drugs are called Prototypes

  • May be the first drugs of this group to be developed (e.g., penicillin for antibiotics, morphine for opioid analgesics)


Drug names

Drug Names

  • Generic Name is related to the chemical name and is independent of the manufacturer (e.g., sertraline)

  • Trade name is designated and patented by the manufacturer (e.g., Zoloft)


American drug laws and amendments

American Drug Laws and Amendments

  • 1938 Food, Drug and Cosmetic Act required proof of safety, authorized factory inspections, established penalties for fraudulent claims

  • 1952 Durham-Humphrey Amendment designated drugs that must be prescribed by a physician and dispensed by a pharmacist (e.g., controlled substances, etc.)


American drug laws cont

American Drug Laws cont.

  • 1970 Comprehensive Drug Abuse Prevention and Control Act; Title II, Controlled Substances Act

  • Categorized according to potential for abuse

  • Regulated distribution of narcotics and other drugs of abuse

  • DEA charged w/enforcing the Controlled Substances Act


Categories of controlled substances

Categories of Controlled Substances

  • Schedule I—not approved for medical use and have high abuse potentials; LSD, heroin, peyote, ecstasy (3,4 methyenedioxy-methamphetamine)

  • Schedule II—used medically. High abuse potential (methadone, meperidine, cocaine, pentobarbital, Tylox)


Categories of controlled substances continued

Categories of Controlled Substances continued

  • Schedule III-less potential for abuse than I and II but may lead to psychological or physical dependence (Vicodin, Tylenol with codeine)

  • Schedule IV-drugs have some potential for abuse (Valium, Dalmane, Klonopin)

  • Schedule V-contain moderate amounts of controlled substances. An example is Lomotil (atropine and diphenoxylate)


Pregnancy categories

Pregnancy Categories

  • Cat. A-studies in pregnant women failed to show risk to the fetus

  • Cat. B- animal studies have failed to show a risk to the fetus but there are no adequate studies in women

  • Cat. C-animal studies have shown an adverse effect on the fetus, no adequate human studies, benefits may outweigh risks


Pregnancy categories cont

Pregnancy Categories cont.

  • Cat. D-positive evidence of human fetal risk

  • Cat. X-animal or human studies have shown fetal abnormalities or toxicity


Pharmacokinetics

Pharmacokinetics

  • Involves drug movement through the body to reach sites of action, metabolism, and excretion

  • Specific processes are absorption, distribution, metabolism and excretion


Pharmacokinetics drug transport pathways

Pharmacokinetics-Drug Transport Pathways

  • Three main pathways of drug movement across cell membrances

  • Most common is direct penetration by lipid soluble drugs

  • 2nd pathway involves passage through protein channels. Gates open and close either by voltage gating or by assist of chemical substances (Na+ and K+ ions affecting some cardiac drugs)


Drug transport pathways cont

Drug Transport Pathways cont.

3. 3rd is by carrier proteins that transport molecules from one side of the cell membrane to the other. An example would be oral drugs that carry hormones to their sites of action

(see text for details)


Pharmacokinetics1

Pharmacokinetics

  • Absorption-process that occurs from the time a drug enters the body to the time it enters the bloodstream to be circulated

  • Factors affecting absorption include: dosage form, route of administration, blood flow to the site of administration, gastrointestinal function, presence of food or other drugs

  • For many medications, food in the stomach slows absorption


Bioavailability

Bioavailability

  • Is the portion of a dose that reaches the systemic circulation and is available to act on body cells

  • IV administration is 100% bioavailable

  • Subcutaneous administrations has more rapid absorption than does the oral route

  • Mucous membranes allow for rapid and direct absorption into the bloodstream


Distribution

Distribution

  • Involves the transport of drug molecules within the body

  • After the drug is absorbed into the bloodstream, it is carried by the blood or tissue fluids to its sites of pharmacologic action, metabolism and excretion

  • Protein binding is an important factor in drug distribution


Distribution cont

Distribution cont.

  • Drug distribution into the CNS is limited because of the blood-brain barrier

  • Blood-brain barrier is composed of capillaries with tight walls which limits movement of drug molecules into brain tissue

  • Only drugs that are lipid soluble or have a transport system can cross the blood-brain barrier and reach therapeutic concentrations in brain tissue


Distribution cont1

Distribution cont.

  • Drug distribution during pregancy and lactation is unique as most drugs cross the placenta or in the case of lactation, pass into breastmilk


Protein binding

Protein binding

  • Most drugs form a compound with plasma proteins, mainly albumin, which act as carriers

  • Only the free or unbound portion of a drug acts on body cells

  • As unbound drug acts on cells, the decrease in plasma drug level causes some of the bound drug to be released

  • Protein binding allows a part of a drug dose to be stored and released as needed


Metabolism

Metabolism

  • Method by which drugs are inactivated or biotransformed by the body

  • Some drugs yield metabolites that are also active and exert effects on the body until they are excreted (normeperidine)

  • Most drugs are lipid soluble which aids their passage across the cell membrane


Metabolism cont

Metabolism cont.

  • Excretion usually is by kidneys. Need to be water soluble for this to occur. Thus, one function of metabolism is to convert fat soluble medications to water soluble ones.

  • Hepatic drug metabolism or clearance is a major mechanism for terminating drug action and eliminating drug molecules from the body


Metabolism cont1

Metabolism cont.

  • Most drugs are metabolized by the cytochrome P450 enzymes in the liver

  • Liver contains complex system of enzymes, three of which are key in the metabolism of medications/drugs


Cytochrome p450

Cytochrome p450

  • CYP enzymes catalyze the chemical reactions which ultimately metabolize the medications

  • With chronic administration (greater than 1-3 weeks), some drugs stimulate hepatocytes to produce larger amounts of drug metabolizing enzymes (inducers). Enzyme induction accelerates drug metabolism. Result is that larger doses of the drug may be need for therapeutic effects.


Cytochrome p4501

Cytochrome p450

  • Enzyme inhibition may occur with concurrent administration of two or more drugs that compete for the same metabolizing enzymes (e.g., Dilantin, EES, Tagamet)

  • Oral meds are generally absorbed by the GI tract and carried to the liver. Drug may undergo extensive metabolism leaving little for systemic use. This is called the first pass effect.


Excretion

Excretion

  • Refers to the elimination of a drug from the body

  • Most are excreted by the kidneys although some are excreted in the bile then the feces


Serum drug levels

Serum Drug Levels

  • Lab measurement of the amount of a drug in the blood at a particular time

  • Minimum effective concentration (MEC)-must be present before a drug exerts its pharmacologic action on body cells

  • Duration of action-time during which serum drug levels are at or above the MEC (may measure serum drug levels when the drugs have a low therapeutic index)


Pharmacodynamics receptors

Pharmacodynamics--Receptors

  • Involves drug actions on target cells and the resulting alterations in cellular biochemical reactions

  • Most drugs chemically bind with receptors at the cellular level

  • Drug-receptor complex initiates physiochemical reactions that stimulate or inhibit cellular functions


Pharmacodynamics receptors1

Pharmacodynamics-receptors

  • Receptors vary in type, location, number and functional capacity

  • When drug molecules chemically bind with cell receptors, pharmacologic effects result from agonism or antagonism


Pharmacodynamics receptors2

Pharmacodynamics-receptors

  • Agonists-are drugs that produce effects similar to those produced by naturally occurring hormones, neurotransmitters and others. Agonists may accelerate or slow normal cellular processes depending on the type of receptor activated.

  • Antagonists—drugsthat inhibit cell function by occupying receptor sites.

  • Not all drugs act on receptors. Examples include: antacids, osmotic diuretics, chelators.


Variables that affect drug actions

Variables that affect drug actions

  • Dosage

  • Route

  • Drug-diet interactions. Food may slow absorption or foods may actually interact with certain medications (tyramine and MAO inhibitors; tetracycline and milk products; ingestion when taking certain antihypertensive medications)


Variables affecting drug actions

Variables affecting drug actions

  • Drug-drug interations-additive effects such as seen with sedatives and ethanol. Synergism as seen with acetaminophen and codeine.

  • Antidote—drug can be given to antagonize the toxic effects of another drug


Variables that affect drug actions1

Variables that affect drug actions

  • Age

  • Pregnancy

  • Body weight

  • Gender-hormonal effects

  • Pathologic conditions

  • Placebo response


Variables that affect drug actions2

Variables that affect drug actions

  • Genetics-hepatic drug metabolizing enzymes===acetyltransferase. Rapid acetylators may need larger than usual dosages and conversely, smaller doses if slow acetylators

  • Glucose-6-phosphate deficiency—develop hemolytic anemia if take antimalarials or sulfonamides

  • Ethnicity—ACE inhibitors in African Americans

  • Tolerance and cross tolerance


Adverse effects of drugs

Adverse effects of drugs

  • CNS

  • GI

  • Hematologic-anticonvulsants

  • Hepatic-acetaminophen, INH

  • Nephrotoxicity-aminoglycosides, NSAIDS

  • Hypersensitivity

  • Drug fever-fever associated w/administration of some antimicrobials, atropine or TCAs


Adverse drug effects

Adverse Drug Effects

  • Drug dependency

  • Idiosyncrasy

  • Carcinogenicity

  • teratogenicity


Toxicology drug overdosage

Toxicology—Drug Overdosage

  • General management

  • CPR

  • ETT

  • IV

  • Check blood sugar, drug screen, liver and kidney function

  • Charcoal

  • Narcan or possibly antidotes

  • May alkalinize the urine to prevent kidney damage


Antidotes for selected therapeutic drugs

Antidotes for Selected Therapeutic Drugs

  • Acetaminophen-mucomyst

  • Digoxin-digibind

  • Beta blockers-Glucagon (increases myocardial contractility)

  • Phenothiazines-benadryl (EPS)

  • Coumadin-vitamin K

  • Heparin-protamine sulfate


Antidotes cont

Antidotes cont.

  • Benzodiazepines—flumazenil

  • Cholinergics-atropine

  • Calcium channel blockers—calcium gluconate


General principles of accurate drug administration

General Principles of accurate drug administration

  • Six Rights

  • Right patient

  • Right drug

  • Right dose

  • Right route

  • Right time

  • Right documentation


General principles cont

General Principles cont.

  • Follow the ‘rights’ consistently

  • Learn essential information about each drug

  • Interpret prescriber’s orders correctly

  • Read labels for right medication and concentration


Drug administration

Drug Administration

  • Minimize the use of abbreviations

  • Calculate dosages correctly

  • Measure doses accurately

  • Use appropriate anatomic landmarks to identify sites of IM injections-follow manufacturers recommendations

  • Verify client identity


Drug administration1

Drug Administration

*****Seek information about the client’s medical diagnoses and condition in relation to drug administration

  • Be especially vigilant with children to avoid errors


Legal responsibilities

Legal Responsibilities

  • Nurse is legally responsible for safe and accurate administration of medications

  • Nurse is expected to have sufficient drug knowledge to recognize and question erroneous orders

  • Unit dose wrappings of oral drugs should be left in place until the nurse is in the presence of the client and ready to administer the medication


Medication orders

Medication Orders

  • Include the full name of the patient

  • Generic or trade name of the drug

  • The dose, the route and frequency of administration

  • Date, time and signature of the prescriber


Common abbreviations

Common abbreviations

  • PO

  • IM

  • IV

  • SL

  • Sub q


Times of drug administration

Times of Drug Administration

  • AC

  • Ad lib

  • bid, tid, qid

  • HS

  • PC

  • PRN

  • Stat


Drug dosages

Drug Dosages

  • cc

  • g

  • Gr

  • gtt

  • mL

  • oz

  • Tsp

  • tbsp


Routes of administration

Routes of Administration

  • Oral

  • Via GI tube

  • Parenteral-IM, IV and sub q

  • Topical

  • Rectal, ophthalmic

  • Otic

  • vaginal


Sites for injections

Sites for injections

  • Sub q-abdomen, thighs, back and upper arms

  • IM-deltoid, dorsogluteal, ventrogluteal and vastus lateralis muscles

  • IV-antecubital, hands, arms, external jugular

  • Others: intradermal, intra-articular, intra-arterial and intrathecal


Equivalents

Equivalents

  • Metric

  • Apothecary

  • Household

  • (see p. 37)


Drug administration cardinal rules

Drug administration cardinal rules

  • Wash hands before giving meds

  • Read MAR carefully. If ever in doubt, check the original order

  • Never give medications you are uncertain of unless you have looked them up or have consulted with pharmacy


Drug administration cardinal rules1

Drug Administration Cardinal Rules

  • Never give more than 3cc per IM injection

  • Wear gloves with all injections

  • For sub q injections, use 25G, 5/8” needles

  • Do not give oral meds if patient is vomiting, sedated, NPO or is unconscious

  • Follow narcotic protocol for signing out of narcotics


Nursing process in drug therapy

Nursing Process in Drug Therapy

  • Is a systematic way of gathering and using information to plan and provide individualized client care and to evaluate the outcomes of care

  • Five steps of the nursing process are: assessment, nursing diagnosis, planning, interventions and evaluation


General principles of drug therapy

General Principles of Drug Therapy

  • Expected benefits should outweigh potential adverse effects

  • Drug therapy should be individualized

  • Drug effects on quality of life should be considered in designing a drug therapy regiment


Drug selection and dosage

Drug selection and dosage

  • Use as few drugs as possible

  • Fixed dose combinations increase compliance

  • Lowest dose with therapeutic effect

  • Follow guidelines but dosages must be individualized

  • Drugs with long half-lives may require loading doses then titrated lower maintenance doses


Drug therapy in special populations pediatrics

Drug Therapy in special populations-pediatrics

  • Pediatrics-all aspects must be guided by the child’s age, weight and level of growth and development

  • Safe therapeutic ranges are less well-defined

  • Choice of drug is restricted because many drugs used in adults have not been sufficiently investigated


Pediatric physiologic characteristics affecting pharmacokinetics

Pediatric physiologic characteristics affecting pharmacokinetics

  • Thin, permeable skin –increased absorption of topicals

  • Immature blood-brain barrier—increased distribution into the CNS until age 2

  • Altered protein binding until age 1

  • Decreased activity of metabolizing enzymes in infants, increased in children


Pediatric physiologic effects

Pediatric physiologic effects

  • Increased percentage of body water

  • Decreased GFR until one year of age


Pediatrics

Pediatrics

  • Oral route for meds is preferable

  • For injections, may wish to use EMLA (eutectic mixture of lidocaine and prilocaine, local anesthetics)

  • Site selection for injections—infants, use thigh muscles; older than 18 months of age, use deltoid; older than 3, use ventrogluteal muscle


Drug therapy in older adults physiologic characteristics and pharmacokinetic impact

Drug Therapy in Older AdultsPhysiologic characteristics and pharmacokinetic impact

  • Decreased GI motility—slower absorption

  • Decreased cardiac output—slower absorption from site of administration, decreased distribution to sites of action in tissues

  • Decreased blood flow to liver and kidneys-delayed metabolism and excretion


Drug therapy in older adults

Drug Therapy in Older Adults

  • Decreased total body water and lean body mass-fat soluble meds stay with patient longer, water soluble drugs are distributed in smaller area, greater risk for toxicity

  • Decreased blood flow to liver-slowed metabolism and detox of drugs


Drug therapy in older adults1

Drug Therapy in Older Adults

  • Decreased albumin-decreased availability of protein for binding and transporting. Will also have higher concentration of free active drug.

  • Decreased blood flow to kidneys—impaired drug excretion, potential toxicity


Older adults renal impairment

Older AdultsRenal Impairment

  • Know baseline renal function

  • Tailor dosages

  • Avoid nephrotoxic medications

  • Be aware of need for additional dosing if patient is receiving renal replacement therapy


Older adults hepatic impairment

Older AdultsHepatic Impairment

  • Those with cirrhosis, hepatitis, receiving hepatotoxic drugs, have heart failure, are undergoing major surgery or have had trauma are at higher risk for toxicities r/t medications

  • Know drug effects on hepatic function

  • Reduce dosages on medications that are extensively metabolized by the liver such as: cimetidine, phenytoin, ranitidine, theophylline


Older adults critical illnesses

Older Adults Critical Illnesses

  • Be aware that all medications may have variable effects in this scenario

  • Know the actions, usual dosages and side effects of medications

  • Closely monitor renal and liver function tests

  • Monitor serum protein and albumin levels


Older adults critical illness

Older AdultsCritical Illness

  • Most drugs will be given IV-for this reason, medications may have faster onset

  • Many factors may interfere with drug effects if given orally

  • Considerations when giving medications via feeding tube

  • Appropriate scheduling very important


Drug therapy in home care

Drug Therapy in Home Care

  • On patient’s turf

  • Schedule visit at convenient time for patient and caregiver

  • Assess patient’s ability to perform self-care

  • Assess patient’s understanding and attitude regarding medication regimen

  • Inquire if patient is taking any herbal preparations


Drug therapy in home care1

Drug Therapy in Home Care

  • Inquire if patient is taking any OTC meds

  • Assess environment for safety

  • Educate patient and caregiver indication, proper administration and side effects of administered medications

  • Between visits, maintain contact with patient to monitor progress and serve as a resource


Herbal and dietary supplements

Herbal and Dietary Supplements

  • Black cohosh-used to relieve menopausal s/s

  • Capsaicin-post-herpetic neuralgia

  • Echinacea-anti-infective, for common cold

  • Ginger—nausea. Not for morning sickness.

  • Garlic-cholesterol lowering


Herbal and dietary supplements1

Herbal and Dietary supplements

  • Feverfew-for migraines, menstrual complaints. Can cause withdrawal s/s.

  • Ginseng-increase stamina, endurance and mental acuity. Can affect bleeding time, BP, increase hypoglycemia. No longer than 3 weeks use with Siberian ginseng.


Questions

Questions


  • Login