Questions and Answers
What type of reaction is mediated by IgG and involves tissue deposition of drug-antibody complexes with complement activation and inflammation?
What is the result of the combination of a hapten with a larger carrier such as a protein?
What is the timing of a Type III reaction?
What is the main mechanism of Type IV reactions?
Signup and view all the answers
What is an idiosyncratic reaction?
Signup and view all the answers
What is the result of the tagging of cells in a hypersensitivity reaction?
Signup and view all the answers
What is a clinical manifestation of serum sickness?
Signup and view all the answers
What type of reaction involves the destruction of RBCs, WBCs, and platelets?
Signup and view all the answers
What is the mechanism of idiosyncratic reactions?
Signup and view all the answers
What is the clinical diagnosis for patients with adverse reactions to two or more structurally unrelated drugs with an underlying immune-mediated mechanism causing the reaction?
Signup and view all the answers
Which type of drug allergy is mediated by IgE antibodies?
Signup and view all the answers
Which of the following are considered main targets of Type 1 anaphylactic reactions?
Signup and view all the answers
Which of the following statements about the fragment constant (Fc) portion of IgE is true?
Signup and view all the answers
What is the main mechanism by which anaphylactic reactions cause vasodilation and inflammation?
Signup and view all the answers
What type of drug allergy is characterized by IgG or IgM antibodies directed at drug-hapten coated cells?
Signup and view all the answers
What type of reaction is termed "immediate hypersensitivity reaction"?
Signup and view all the answers
What is the typical timing of anaphylactic reactions after drug exposure?
Signup and view all the answers
What is the primary concern for patients with a history of multiple drug allergies?
Signup and view all the answers
What does the therapeutic index indicate about a drug?
Signup and view all the answers
Which type of adverse drug reactions (ADRs) are predictable and related to pharmacologic actions?
Signup and view all the answers
What accounts for less than 10% of all adverse drug reactions?
Signup and view all the answers
Which factor is NOT a risk factor for drug allergy?
Signup and view all the answers
What can lead to genotoxic reactions from drugs?
Signup and view all the answers
Which statement about clinical sensitization is true?
Signup and view all the answers
What is one way in which a drug can cause allergic reactions?
Signup and view all the answers
Which route of administration has been associated with severe allergic reactions?
Signup and view all the answers
Which of the following is a characteristic of idiosyncratic reactions?
Signup and view all the answers
What is a potential outcome of drug interactions?
Signup and view all the answers
Which term describes the scenario where two drugs produce an effect that is less than the sum of their individual effects?
Signup and view all the answers
What is the primary goal when treating poisoning?
Signup and view all the answers
What is the initial step in decontamination after poisoning?
Signup and view all the answers
What technique involves the removal of drugs from the body by filtering the blood extracorporeally?
Signup and view all the answers
Which method of gastric emptying can be used in children and adults following poisoning?
Signup and view all the answers
What is a contraindication for the use of syrup of Ipecac?
Signup and view all the answers
What type of antidote functions by forming an inert complex with a poison?
Signup and view all the answers
Which antidote acts as a glutathione substitute to detoxify hepatotoxic paracetamol metabolites?
Signup and view all the answers
How is gastric lavage usually performed in adults?
Signup and view all the answers
Which strategy is NOT a primary approach for gastrointestinal decontamination?
Signup and view all the answers
Which substance inhibits the metabolism of methanol to its toxic metabolites?
Signup and view all the answers
What are toxidromes?
Signup and view all the answers
What method uses oxygen to bypass toxic effects in cyanide poisoning?
Signup and view all the answers
Which antidote is known for competitively displacing poisons from receptor sites?
Signup and view all the answers
Which antidote blocks the effects of anti-ChE agents such as organophosphate compounds?
Signup and view all the answers
What is the action of thiosulphate in relation to cyanide?
Signup and view all the answers
Which type of antidote utilizes a different cellular mechanism to counteract a poison?
Signup and view all the answers
Study Notes
Toxicology Overview
- Toxicology studies adverse effects of chemicals on living organisms.
- Higher therapeutic index indicates a safer drug.
Adverse Drug Reactions (ADRs)
- Broadly classified into predictable and unpredictable reactions.
- Predictable ADRs include dose-dependent reactions and drug interactions.
- Unpredictable ADRs arise from immunological responses and genetic differences.
- ADRs contribute to 3% to 6% of hospital admissions and affect 10% to 15% of hospitalized patients.
Types of Therapeutic Drug Toxicity
- Dose-dependent reactions: Severity linked to drug concentration and exposure duration.
- Allergic reactions: Mediated by the immune system, causing less than 10% of ADRs.
- Idiosyncratic reactions: Unique adverse effects not explained by drug mechanisms.
- Drug-drug interactions: Altered absorption, binding, biotransformation, or excretion rates.
Dose Dependent Reactions
- Include pharmacological (dose-related), pathological (overdose findings), and genotoxic (DNA injury).
Allergic Reactions
- Caused by previous sensitization; most reactions occur 1-2 weeks post-exposure.
- Drug allergy prevalence is low, but misdiagnoses in children are common.
Risk Factors for Drug Allergy
- Drug factors: Chemical nature and changes in exposure levels can influence allergy risk.
- Host factors: Age, underlying health conditions, and previous drug reactions can predispose individuals to allergies.
Drug Allergy Mechanisms
- Four categories based on immunological involvement:
- Type 1: Anaphylactic reactions mediated by IgE, resulting in rapid symptoms.
- Type II: Cytolytic reactions involving IgG or IgM targeting drug-coated cells.
- Type III: Arthus reactions characterized by immune complex deposition and delayed symptoms.
- Type IV: Delayed hypersensitivity reactions mediated by T-lymphocytes.
Idiosyncratic Reactions
- Result from abnormal individual reactivity due to genetic factors or enzyme variability.
- Do not follow typical drug therapy patterns.
Drug-Drug Interactions
- Can lead to additive, synergistic, potentiated, or antagonistic effects on pharmacodynamics.
Prevention of Poisoning
- Adhere to the “5 Rights” for safe medication administration (right drug, patient, dose, route, and time).
Principles of Treatment of Poisoning
- Maintain vital functions while reducing poison concentrations in tissues.
- Identification of clinical patterns known as toxidromes aids in diagnosis.
Decontamination Strategies
- Involves stopping further exposure and employing gastrointestinal decontamination methods (gastric emptying, adsorption, irrigation, catharsis).
Gastric Emptying Techniques
- Induced vomiting with syrup of ipecac can generally produce quick emesis, but has contraindications.
- Gastric lavage involves the insertion of an orogastric tube for stomach content removal.
Extracorporeal Techniques
- Techniques include peritoneal dialysis, hemodialysis, or hemoperfusion for certain drug elimination.
Antidotal Therapies
- Chemical antidotes neutralize toxins; pharmacologic antidotes compete with poison at receptor sites; physiological antidotes work via different cellular mechanisms.
Mechanisms of Antidotal Action
- Inert complex formation, accelerated detoxification, reduced toxic conversion, receptor site competition, receptor site blockade, and toxic effect bypass (e.g., 100% oxygen for cyanide) are key antidotal mechanisms.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
A quiz on toxicology, focusing on adverse drug reactions, therapeutic index, and the effects of chemicals on living organisms.