Adverse drugeffects

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  • 1.Detecting and ManagingAdverse Drug Reactions

2. Adverse Drug Reaction

  • Unexpected, undesired, excessive response t o a medication that results in
    • Temporary or permanent serious harm or disability
    • Admission to a hospital
    • Transfer to a higher level of care
    • Prolonged stay
    • Death

3. Incidence of Adverse Drug Events (ADEs)

  • The FDA entered 441,367 reports of adverse drug events in 2008
  • AdverseDrugEffects/ucm070434.htm
  • 10.7% of hospital admissions in older adults are associated with adverse drug reactions
  • Kongkaew C, et al. Hospital admissions associated with adverse drug reactions: a systematic review of prospective observational studies. Ann Pharmacother 2008; 42:1017-25 .

4. Types of Adverse Drug Effects

  • Dose-related (toxic) reactions
  • Drug-drug and drug-food interactions
  • Hypersensitivity (allergic reactions)
  • Idiosyncratic reaction

5. Dose-Related (Toxic) Reactions

  • May be related to
    • Renal or hepatic impairment
    • Extremes in age (neonates, elderly)
    • Drug-drug or drug-food interactions
    • Underlying illnesses
    • Inadequate assessment of blood levels

6. Dose-Related Reactions

  • Examples of medications that require careful monitoring or lab tests
    • Digoxin, lithium
    • Aminoglycosides
    • Antiepileptic drugs
    • Anticoagulants
    • Nephrotoxic drugs

7. Dose-Related Reactions (Contd)

  • Medical Management
    • Discontinue drug temporarily
    • Reduce dose or increase dosing interval
    • Provide antidote (e.g., Digibind for digoxin toxicity)
    • Get careful, well-timed drug-level monitoring
    • Review all medication
    • Consider dietary change (e.g., eliminate grapefruit or grapefruit juice)

8. Dose-Related Reactions (Contd)

  • Nursing Responsibilities
    • Review all medications andpatient history
    • Administer meds at thecorrect time
    • Obtainblood levelsas ordered; coordinate administration with lab technician
    • Assess forsigns and symptoms of toxicity
    • Provideeducationabout drugs and diet
    • Report relevantlab values

9. Hypersensitivity Reactions

  • Can be allergic or nonallergic
  • Anaphylactic (allergic) reactions
    • Occur minutes to hours after exposure and are manifested by
      • Urticaria (hives), pruritis (itching)
      • Bronchospasm, wheezing
      • Vomiting, diarrhea
      • Circulatory collapse
  • A life-threatening medical emergency!

10. Hypersensitivity Reactions (Contd)

  • Nonallergic hypersensitivity reactions occur within 2 days or up to 3 weeks and are manifested by
      • Hemolytic anemia, glomerulonephritis
      • Lymphadenopathy, thrombocytopenia, neutropenia
      • Arthralgia

11. Hypersensitivity Reactions (Contd)

  • Nonallergic, hypersensitivity reactionsinclude
      • Erythema multiforme
      • StevensJohnson syndrome
      • Toxic epidermal necrolysis
      • Contact dermatitis
  • Require prompt recognition and treatment because of high morbidity and mortality

12. Hypersensitivity Reactions (Contd)

  • Nursing Responsibilities
  • Ask patient or family about allergies on admission; document prominently and obtain allergy bracelet
  • When anaphlaxis occurs stop the drug, assess ABCs(airway, breathing, circulation)
  • Notify physician, nurse practitioner, or physician assistant immediately

13. Hypersensitivity Reactions (Contd)

  • Nursing Responsibilities (Contd)
  • Stay with the patient
  • Maintain IV access
  • Ensure ready access toemergency resuscitative equipment
  • Monitor during initial administration of cross-hypersensitive agent

14. Drug-Drug Interactions Pharmacokineticandpharmacodynamicproperties ofone drugaffect either thepharmacokinetics or pharmacodynamics of another drug . 15. Drug-Drug Interactions (Contd)

  • Pharmacokinetics
      • Absorbing
      • Distributing
      • Metabolizing
      • Excreting
  • What the body does to the drug

16. Drug-Drug Interactions (Contd)

  • Pharmacodynamics
      • The chemical and physiologic changes that the drug causes
      • Drug effect
  • What the drug does to the body

17. Types of Drug-Drug Interactions

  • Potentiation:Drugs with similar actions cause an additive effect
      • Coumadin and aspirin taken together cause excessive bleeding
      • Sedatives and alcohol cause excessive sedation

18. Types of Drug-Drug Interactions (Contd)

  • Interference:One drug accelerates or slows the metabolism or excretion of another drug
    • Erythromycintaken with
    • Digoxin = elevated blood levels of digoxin
    • Coumadin = enhanced action of Coumadin
    • Potential for serious adverse effects!

19. Types of Drug-Drug Interactions (Contd)

  • Displacement:Two drugs compete for protein binding sites
    • One drug wins (is bound to protein)
    • Displaced drug is active in greater quantities
    • Same effect as taking a higher dose of the displaced drug!
  • A major cause of drug-drug interactions!

20. Types of Drug-Drug Interactions (Contd)

  • Antagonism:One drug decreases the effectiveness of another drug because of divergent actions
    • Oral ketoconazole (Nizoral) is absorbed in an acidic environment
    • H2-receptor antagonists or proton pump inhibitors decrease acidity in the stomach
    • Differing action decreases Nizoral effectiveness

21. Types of Drug-Drug Interactions (Contd)

  • CYP450 enzymes and drug-drug interactions
    • CYP450 Inhibitors:Drug A inhibits CYP450 enzymes in the liver; slows metabolism of drug B, toxic levels of drug B accumulate
    • CYP450 Inducers:Drug A stimulates production of CYP450 enzymes; increases rate of metabolism of drug B, clears drug B out of the system faster
  • A major source of drug-drug interactions!

22. Drug-Drug Interactions

  • Nursing Responsibilities
  • Check your Drug Guide for interactions (e.g., check lopinavir/ritonavir inDaviss Drug Guide for Nurses )
  • Check labs for drug levels
  • Assess patient for increased or decreased drug effects or side effects

23. Drug-Food Interactions

  • Similar to drug-drug interactions
  • Food canalter the absorption or metabolismof medications
  • Diets canalter the bacterial floraof the intestine and may affect the metabolism of certain drugs

24. Drug-Food Interactions (Contd)

  • MAOstaken withtyramine -containing foods can cause hypertension and intracranial bleeding
  • Foods high inVitamin Kcause an antagonistic effect withoral anticoagulants
  • Dairy productscause decreased absorptionoft etracyclineand can potentiate or interfere with drug reactions

25. Drug-Food Interactions (Contd)

  • Calcium channel blockerstaken withgrapefruit juicecan increase effects of the drug
  • Irontaken withacidic foodscan cause increased iron absorption