Chapter 5: Adverse Drug Reactions Flashcards
adverse drug reactions
Defined by the World Heath Organization:
Any noxious, unintended, and undesired effect that occurs at normal drug doses
Excludes excessive dosages
Can range from annoying to life-threatening
Most common in the elderly and the very young
Risk increased by severe illness
ADR stats
AHRQ (agency for healthcare research quality) (2018): Dramatic rise in adverse drug reactions
Adverse drug reactions: More than 1,100,000 outpatients sought emergency treatment for adverse drug reactions
Hospitalized patients: over 1,735,500 experienced adverse outcomes as a result of drug reactions and medical errors
Of these 1,735,500, more than 53,800 died
side effect
A nearly unavoidable secondary drug effect produced at therapeutic doses
May develop soon after drug is initiated or not until drug has been taken for weeks or months
toxicity
Formal definition: Adverse drug reaction caused by excessive dosing
May occur even with normal dosing
Neutropenia (risk for infection) and anticancer medications
detrimental physiologic effect
allergic reactions
Immune response
Determined primarily by the degree of sensitization of the immune system rather than by drug dosage
Patient’s sensitivity to a drug can change over time
Very few drugs cause severe allergic reactions
Penicillins are the most common
Allergies may also be induced by sulfonamides (diuretics, antibiotics, and oral hypoglycemic agents)
idiosyncratic effect
An uncommon drug response resulting from a genetic predisposition
Succinylcholine-induced paralysis
Usually brief but may last for hours in genetically predisposed patients
paradoxical effect
The opposite of the intended drug response
For example, when using benzodiazepines for sedation to treat insomnia, excitement may occur instead (especially in children and older adults)
iatrogenic disease
Iatrogenic: Literally, “a disease produced by a physician”; also used to refer to a disease produced by drugs (e.g., drugs for antipsychotic disorders can cause Parkinson-like symptoms)
Sometimes also called drug-induced disease
Essentially identical to naturally occurring pathology
physical dependence
Develops during long-term use of certain drugs (opioids, alcohol, barbiturates, and amphetamines)
A state in which the body has adapted to drug exposure in such a way that an abstinence syndrome will result if drug use is discontinued
Important to warn patients against abrupt discontinuation of any medication without first consulting a knowledgeable health professional
carcinogenic effect
Only a few therapeutic agents are carcinogenic
Several drugs used to treat cancer are among those with the greatest carcinogenic potential
Evaluating drugs is difficult; it may take decades for evidence of carcinogenesis to appear after exposure
An example of this is diethylstilbestrol (DES)
tetratogenic effect
drug-induced birth defect
organ-specific toxicity
Many drugs are toxic to specific organs, such as the liver or heart
Common examples include:
Kidneys: Amphotericin B (antifungal)
Heart: Doxorubicin (anticancer)
Lungs: Amiodarone (antidysrhythmic)
Inner ear: Aminoglycoside (antibiotic)
hepatotoxic drugs
Leading cause of liver failure in the United States
More than 50 drugs are known to be hepatotoxic
As some drugs undergo metabolism, they are converted to toxic products that can injure liver cells
Combining hepatotoxic drugs may increase the risk for liver damage (e.g., acetaminophen and alcohol)
Monitor aspartate aminotransferase (AST) and alanine aminotransferase (ALT) for liver injury
Watch for signs of liver injury; educate patients about jaundice, dark urine, light-colored stools, nausea, vomiting, malaise, abdominal discomfort, and loss of appetite
QT interval drugs
QT interval: Measure of the time required for the ventricles to repolarize after each contraction
QT drugs: Drugs that prolong the QT interval on electrocardiogram (ECG)
Creates serious risk of life-threatening dysrhythmias
Examples: Torsade’s de pointes, ventricular fibrillation
minimize risk of QT interval drugs
Most patients are at higher risk, including women, older adults, and patients with bradycardia, congestive heart failure (CHF), congenital QT prolongation, low potassium, and low magnesium
Do not use two QT drugs concurrently
identifying ADRs
Can be very difficult to determine whether a specific drug is responsible for an observed adverse event
Other factors to consider: Underlying illness and Other drugs
Did symptoms appear shortly after the drug was first used?
Did symptoms abate when the drug was discontinued?
Did symptoms reappear when the drug was reinstituted?
Is the illness itself sufficient to explain the event?
Are other drugs in the regimen sufficient to explain the event?
ADR to new drugs
Half of all new drugs have serious adverse drug reactions that are not revealed during Phase II and Phase III trials
Be alert for unusual responses when giving new drugs, because newly released drugs may have as-yet-unreported adverse effects
Drugs that are suspected of causing a previously unknown adverse effect should be reported to MedWatch, the FDA Medical Products Reporting Program
ways to minimize ADRs
Responsibility for reducing ADRs lies with everyone associated with drug production and usage:
Pharmaceutical industry: Strive to produce the safest medications possible
Prescriber: Select the least harmful drug; balance potential risks with probable benefits
Nurse: Evaluate patient for ADRs; educate patients and families about how to minimize harm
Patients and families: Watch for signs that an ADR may be developing; see medical attention if one appears
The anticipation of ADRs can help to minimize them
Target the evaluation of the function of any at-risk organs
Important sites of toxicity:
Liver: Signs of jaundice; monitor liver function tests
Kidney: Routine urinalysis and serum creatinine level (periodic creatinine clearance testing)
Bone marrow: Periodic blood cell counts
Patients with chronic disorders are especially vulnerable to ADRs
medication guides
FDA-approved documents created to educate patients about how to minimize harm from potentially dangerous drugs
Required when the FDA has determined that (1) patient adherence to directions for drug use is essential for efficacy and (2) patients need to know about potentially serious effects when deciding whether to use a drug
boxed warnings
Also known as black box warnings
Strongest safety warning a drug can carry and still remain on the market
Purpose of this warning is to alert prescribers to:
Potentially severe side effects (e.g., life-threatening dysrhythmias, suicidality, major fetal harm)
Ways to prevent or reduce harm (e.g., avoiding a teratogenic drug during pregnancy)
risk eval and mitigation strategies (REMs)
REMS: A plan to minimize drug-induced harm
For example, the REMS for isotretinoin is called iPLEDGE
Isotretinoin can cause serious birth defects
iPLEDGE was designed to ensure that those who are pregnant or who may become pregnant will not have access to the drug
what is a medication error and who makes them
The risk for error in hospitals is high because each medication order is processed by several people
The nurse is the last person in this sequence
Thus, the nurse is the last line of defense against mistakes
This places a heavy responsibility on the nurse to ensure patient safety
ways to reduce medication errors
Help and encourage patients and their families to be active and informed members of the health care team
Give health care providers the tools and information they need to prescribe, dispense, and administer drugs as safely as possible
Institute safety checklists for high-alert drugs
About 20 drugs cause 80% of medication error–related deaths
Replace handwritten medication orders with a computerized order entry system
Have a senior clinical pharmacist accompany physicians on rounds
Do not use error-prone abbreviations
Perform medication reconciliation
how to report medication errors
Medication Errors Reporting (MER) program:
Reporting is confidential
Reporting can be done by phone, fax, or Internet
Program encourages all health care providers—including pharmacists, nurses, physicians, and students—to report errors
https://www.ismp.org/orderforms/reporterrortoismp.asp
All information is forwarded to the U.S. Food and Drug Administration (FDA), the Institute for Safe Medication Practices (ISMP), and the product manufacturer
