Adverse rxns

• Adverse drug reactions


  Any noxious, unintended and undesired effect that occurs at normal drug doses
• Adverse drug reactions are more common in elderly patients
• Occurrence of adverse drug reactions for inpatients

  Decreased
• Occurrence of adverse drug reactions for outpatients

  Increased
• Most outpatient adverse drug reactions are preventable
• Side effect


  An unavoidable secondary drug effect produced at therapeutic doses
• Side effects


  • Drowsiness from antihistamines
  • Gastric irritation from aspirin
• Side effects


  Generally predictable and their intensity is dose dependent
• Some side effects develop soon after drug use starts, others may not appear until weeks or months
• Toxicity


  The degree of detrimental physiologic effects caused by excess of drug dosing
• Toxicity


  • Respiratory depression from morphine overdose
• Allergic reaction


  An immune response that requires prior sensitization of the immune system
• Allergic reactions


  • Mild itching
  • Severe rash
  • Anaphylaxis
• Intensity of allergic reaction is determined by degree of immune system desensitization, not drug dosage
• Most serious allergic reactions are caused by penicillins
• Drugs that can cause allergic reactions

  • Anti-inflammatory drugs
  • Sulfonamide groups (diuretics, antibiotics, oral hypoglycemic agents)
• Idiosyncratic effect


  An uncommon drug response resulting from genetic predisposition
• Idiosyncratic effect


  • Hemolysis in people with glucose-6-phosphate dehydrogenase deficiency from sulfonamides or aspirin
• Paradoxical effect


  Opposite of intended drug response
• Paradoxical effects


  • Excitement in children from antihistamines
  • Excitement in older adults from benzodiazepines
• Iatrogenic disease


  A disease produced by medical care or treatment, identical to naturally occurring diseases
• Iatrogenic disease


  • Parkinson's-like syndrome from antipsychotic drugs
• Physical dependence


  A state where the body has adapted to drug exposure such that abstinence syndrome will result if the drug is discontinued
• Drugs that can cause physical dependence

  • Opioids
  • Alcohol
  • Barbiturates
  • Amphetamines
• Physical dependence can also develop from drugs that work outside the central nervous system
• Abrupt discontinuation of any medication without consulting a health professional should be avoided
• Carcinogenic effect


  The ability of certain medications and environmental chemicals to cause cancers
• Teratogenic effect


  Drug-induced birth defects
• Drugs are the leading cause of liver failure in the US, with over 50 known hepatotoxic drugs</b>
• Combining certain drugs (e.g. acetaminophen and alcohol) can increase risk of liver damage
• To prevent liver injury, monitor AST, ALT, and watch for signs like jaundice, dark urine, light stools, nausea, etc.
• QT interval drugs


  Medications that can prolong the QT interval on the ECG, leading to torsades and fatal ventricular fibrillation
• Persons at high risk for QT interval prolongation include older women, those with bradycardia, heart failure, congenital QT prolongation, low potassium/magnesium
• Do not prescribe two QT-prolonging drugs concurrently
• Identifying adverse drug reactions

  1. Did symptoms appear shortly after drug use?

  2. Did symptoms abate when drug was discontinued?

  3. Did symptoms reappear when drug was reinstituted?

  4. Is the illness itself sufficient to explain the event?

  5. Are other drugs in the regimen sufficient to explain the event?
• Half of all new drugs have serious adverse effects not detected in clinical trials
• Newly released drugs may have unreported adverse effects, so be alert when prescribing them
• Suspected new adverse effects should be reported to the FDA's MedWatch program
• Responsible parties for reducing adverse drug reactions

  • Pharmaceutical industry
  • Healthcare providers
  • Patients and families
• Anticipating and minimizing adverse drug reactions

  1. Target evaluation of at-risk organ function

  2. Monitor for signs of toxicity (liver, kidneys, bone marrow)

  3. Take extra precautions in patients with chronic disorders