Chapter 5 - Adverse Drug Effects and Drug Interactions

Question 1

Adverse Drug Effect

Answer 1

Undesirable and potentially harmful action caused by the administration of medication

Question 2

Side effects

Answer 2

• Nearly unavoidable secondary drug effect produced at therapeutic doses
  
  • Examples include drowsiness and nausea. Usually predictable, intensity dose-dependent.
  • May occur initially or weeks later.
  • Less serious or severe unwanted drug action

Question 3

Toxicity

Answer 3

• Detrimental physiological effects caused by excessive drug dosing
  
  • Examples include respiratory arrest d/t overdose of morphine or severe hypoglycemia d/t overdose of insulin.

Question 4

Adverse Event Reporting System (FAERS)

Answer 4

• FDA’s voluntary program that encourages healthcare providers and consumers to report suspected adverse effects directly to FDA or the manufacturer
  
  • Reports to the manufacturer, by law, are sent to FDA.
• Data from FAERS is used to monitor adverse effects of drugs that could lead to additional testing, black bock warning, restricting drugs from certain populations, recalling a product, etc.

Question 5

Drug allergies

Answer 5

• Common events 6-10% of adverse effects
• Immune response triggers allergic reaction
• Occur with very small amounts of drug
• Intensity range from mild rash to anaphylaxis with bronchospasm, laryngeal edema and hypotension.

Some drugs have higher incidence

• Penicillins and related antibiotics, insulin, aspirin

Patients may report allergic response as ann adverse effect

Question 6

Idiosyncratic Effect

Answer 6

• Idiosyncratic - historically used to describe any drug effect that cannot be explained
• Produces unusual and unexpected symptoms. Not allergic reactions as they are not immune response related
• Many are related to individual genetic differences. Genetic predisposition (African and Mediterranean ancestry).
• Uncommon ADR r/t G6PD deficiency
  
  • Taking Aspirin and Sulfonamides can lead to life-threatening RBC hemolysis in people with this enzyme deficiency.

Question 7

Paradoxical Effect

Answer 7

Opposite of what the drug intends to do, including excitement in children/older adults when given benzodiazepines for sedation.

Question 8

Carcinogenic Effect

Answer 8

• The ability of certain medications and environmental chemicals to cause cancers.
• Few on the market, most are those meant to treat cancer have the greatest carcinogenic potential.
  
  • Antineoplastic, immunosuppressants, hormonal agents
  • Antineoplastic - with the goal of eliminating cancer cells some cause mutations in DNA, and what is not repaired by enzymes can accumulate and cause cancer down the line.
  • Immunosuppressants - dampens the immune system that removed cancer cells
  • Hormonal agents or antagonists - more research needed.
• Cause/Effect of agents difficult as disease often not seen for years. Cancer risk is hard to determine with clinical trials before released may take years of use to make the correlation.
• Risk-benefit ratio

Question 9

Teratogenic Effect

Answer 9

Drugs causing birth defects are called teratogens.

Question 10

Iatrogenic Disease

Answer 10

• Develops as a result of another form of medical treatment or advice provided to a patient
  
  • For example, antipsychotic meds can precipitate Parkinson’s like symptoms.

Question 11

Toxicity specific to organ

Answer 11

Most drugs have adverse effects that are specific to a particular organ

• Bone marrow toxicity
• Cardiotoxicity
• Dermatologic toxicity
• Hepatotoxicity
• Nephrotoxicity
• Neurotoxicity
• Skeletal muscle and tendon toxcity

Question 12

Drug interactions

Answer 12

• Occurs when a substance increases or decreases a drug’s action
  
  • May be another drug, dietary substance, food, ect.
• Many go unnoticed and untreated
• Some are important because they are known to cause adverse effects or treatment outcomes
• 3 basic effects: Actions of medication
  
  • Inhibited
  • Enhanced
  • New and different response

Question 13

Drug interactions: pharmacokinetic

Answer 13

• Includes changes in:
  
  • Absorption
  • Distribution
  • Metabolism
  • Excretion

Question 14

Drug Interactions: pharmacodynamic

Answer 14

• When two drugs compete for the same receptor or activate receptors that have the opposite effect
  
  • Enhanced or inhibited
  • Desirable or undesirable
  • Additive effect -two drugs from a similar therapeutic class produce a combined summation response
    
    • Ex. diuretic and beta-blocker used to lower blood pressure
  • Synergistic effect - the effect of the two drugs is greater than would be expected
  • Antagonist affect - drug action being “cancelled”
  • A drug is an antagonist to another. Can be used to minimize an adverse effect
    
    • Ex. Narcan is a narcotic antaginist

Question 15

Medication Guides - MedGuides

Answer 15

FDA documents to inform patients about drug information - name, dosing, side effects, precautions, safe and effective use.

Question 16

Minimizing ADRs

Answer 16

• Nurses need to know common ADRs of drugs
• Monitor patients closely for s/s of toxicity
• Avoid drugs in those with confirmed allergies
• Avoid teratogens if + pregnancy.

High Risk Patients - Older adults, patients with bradycardia, heart failure, congenital QT prolongation, low K+, Mg++, (Women tend to have longer baseline QTc).

See BB for list of offending drugs (methadone, cocaine, hydroxyzine, ondansetron, antipsychotics, SSRIs, AEDs)

Question 17

Black Boxed Warnings

Answer 17

Strong safety warning for drug still on market, alert prescribers to potential harm such as life-threatening dysrhythmias, suicidality, and fetal harm and ways to reduce the risk.