Toxic Effects of Drugs

Adverse Drug Reaction

• Definition
  • Adverse effects are undesired effects that may be unpleasant or even dangerous
• Reasons adverse drug reactions occur:
  • The drug may have other effects on the body besides the therapeutic effect
  • The patient is sensitive to the drug given
  • The drug’s action on the body causes other responses
  • The patient is taking too much or too little of the drug

Types of Adverse Reactions

• Primary actions
  • Overdose: extension of the desired effect
• Secondary actions
  • Undesired effects produced in addition to the pharmacologic effect
• Hypersensitivity reactions
  • Excessive response to the primary or secondary effect of the drug

Types of Drug Allergies

• Anaphylactic reaction
• Cytotoxic reaction
• Serum sickness reaction
• Delayed allergic reaction

Variety of Adverse Effects Associated With Drug Use

Drug-Induced Tissue & Organ Damage

Dermatologic Reactions

• Rash/hives
  • Assessment
    • Abnormalities in the skin, red areas, blisters
  • Interventions
    • May need to discontinue the medication
• Stomatitis
  • Assessment
    • Inflammation of the mucous membranes
  • Interventions
    • Frequent mouth care

Drug-Induced Tissue and Organ Damage

• Superinfections: destruction of the body’s normal flora
  • Assessment
    • Fever, diarrhea, and vaginal discharge
  • Interventions
    • Supportive care (mouth/skin care), give antifungal medications, stop drug responsible for the infection
• Blood dyscrasia: bone marrow suppression
  • Assessment
    • Fever, chills, and weakness
  • Interventions
    • Monitor blood counts and protective isolation

Toxicity

• Liver
  • Assessment
    • Fever, nausea, jaundice, change in color of urine or stool, and elevated liver enzymes
  • Interventions
    • Discontinue medication
• Kidney
  • Assessment
    • Change in urinary pattern or elevated BUN and creatinine
  • Interventions
    • Notify physician, stop medication, or decrease dosage

Poisoning

• Poisoning occurs when an overdose of a drug damages multiple body systems
• Damage to multiple systems can lead to a fatal reaction

Altered Glucose Metabolism

• Hypoglycemia
  • Assessment finding: low serum blood glucose level
  • Intervention: restore glucose to the body (D50)
• Hyperglycemia
  • Assessment finding: high serum glucose level
  • Intervention: administer medications to decrease glucose level (insulin)

Electrolyte Imbalances

• Hypokalemia
  • Assessment finding: decrease in serum potassium level
  • Interventions: replace serum potassium (IV or oral supplement) and monitor serum level of potassium
• Hyperkalemia
  • Assessment finding: increase in serum potassium level
  • Interventions: decrease the serum potassium concentration (using sodium polystyrene sulfonate), monitor serum level of potassium, and monitor cardiac rhythm

Sensory Effects

• Ocular toxicity
  • Assessment finding: visual changes
  • Interventions: monitor for visual changes when giving medication known to cause ocular damage; discontinue medication after notifying physician
• Auditory damage
  • Assessment finding: damage to the eighth cranial nerve
  • Interventions: monitor for hearing loss; discontinue medication after notifying physician

Neurologic Effects

• General central nervous system (CNS) effects
  • Assessment: altered level of consciousness
  • Intervention: prevent injury
• Atropine-like (anticholinergic) effects
  • Assessment: dry mouth, urinary retention, and blurred vision
  • Interventions: sugarless lozenges to keep mouth moist; advise the patient to void before administration of the medication
• Parkinson-like syndrome
  • Assessment: muscle tremors and changes in gait
  • Intervention: discontinue medication
• Neuroleptic malignant syndrome
  • Assessment: extrapyramidal symptoms
  • Intervention: discontinue medication

Teratogenicity

• Drugs may harm the developing fetus or embryo
• Prevent teratogenicity through teaching
  • Advise pregnant women that any medication may adversely affect the baby
  • Weigh the actual benefits against the potential risks
  • Advise pregnant women that they should not take medications without checking with their health care provider first