Pharmacology: Adverse Drug Reactions

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Questions and Answers

Which of the following best describes how drugs work within the body?

They exert highly specific effects with no unintended consequences.

They lack absolute specificity, which can lead to both desired and undesirable effects. (correct)

They always act in a completely predictable and reliable manner.

They produce only therapeutic effects, avoiding any adverse reactions.

An adverse drug reaction is best defined as:

A reaction that is always beneficial at the therapeutic dosage prescribed by a doctor.

A predictable response to a drug always related to the size of the dose.

A rare effect to a drug that only occurs when it is given intravenously.

An undesirable, potentially harmful response that occurs at usual therapeutic doses. (correct)

What is a key characteristic of a toxic reaction to a drug?

It is not dose-related and the effect it has is random.

It is an exaggerated response on target tissues and is dose-related. (correct)

It is a result of the body’s immune system and cannot be predicted.

It occurs in only a small percentage of users and does not depend on the drug.

A patient taking ibuprofen for pain experiences an upset stomach. This is an example of:

A side effect of the drug, not a desired action. (B) Signup and view all the answers

Which of the following statements is true regarding drug allergies?

They are a hypersensitivity response in which the body acts as if the drug is a foreign antigen. (B) Signup and view all the answers

What distinguishes a drug allergy from a toxic reaction when dealing with adverse drug reactions?

Drug allergies are not dose-related, while toxic reactions are. (B) Signup and view all the answers

Which of the following is NOT considered a category of adverse drug reactions based on the content?

Pharmacokinetic Reaction (C) Signup and view all the answers

If a patient experiences an unexpected effect after taking a drug, where the response is peculiar to them, what type of adverse reaction is this considered?

An idiosyncratic reaction, that is not easily predictable. (D) Signup and view all the answers

Which of the following is a characteristic of a Type I drug allergy?

It can manifest as anaphylactic shock, rhinitis, or urticaria (D) Signup and view all the answers

What is the primary characteristic of a local reaction to a drug?

Tissue irritation at the administration site (A) Signup and view all the answers

A patient experiences hemolytic anemia after taking penicillin. Which type of drug reaction is most likely the cause?

Type II (C) Signup and view all the answers

Which of the following is a distinguishing feature of Type III drug reactions?

They involve the deposition of antigen-antibody complexes in vascular endothelium (C) Signup and view all the answers

Which term refers to an agent that can cause developmental abnormalities during pregnancy?

Teratogen (C) Signup and view all the answers

A patient develops contact dermatitis after wearing cheap jewelry. This is likely which type of reaction?

Type IV, delayed hypersensitivity (D) Signup and view all the answers

Which of the following is a drug interaction that can alter the effect of a drug?

Drug-disease (A) Signup and view all the answers

In toxicological evaluations, what does the median effective dose (ED50) represent?

The dose required to produce a specified intensity of effect in half of the animals (C) Signup and view all the answers

What is a key characteristic of an idiosyncratic drug reaction?

It is neither a side effect nor an allergic reaction and is often genetically related. (B) Signup and view all the answers

Which situation best exemplifies a drug interfering with natural defense mechanisms?

A patient with a reduced immune response after using corticosteroids for an extended time. (B) Signup and view all the answers

Which of the following drugs is NOT considered safe for use during pregnancy?

Benzodiazepines (D) Signup and view all the answers

Which reaction is likely to develop 2-3 weeks after exposure?

Serum sickness (C) Signup and view all the answers

What is the potential long-term effect of using drugs considered teratogenic during pregnancy?

Congenital malformations and developmental abnormalities (C) Signup and view all the answers

Which local effect might an injectable drug cause at the injection site?

Tissue necrosis (C) Signup and view all the answers

A patient experiences a rapid onset of hypotension, bronchospasm, and laryngeal edema shortly after receiving an injection. Which type of drug allergy is most likely responsible?

Type I (A) Signup and view all the answers

What does the term 'lethal dose' refer to in the context of toxicological evaluations?

The dose that kills half of the experimental animals (B) Signup and view all the answers

Study Notes

Adverse Reactions

Drugs are used to achieve desired effects but can also produce undesirable or adverse reactions.
Drugs lack absolute specificity, meaning they may act on unintended targets, leading to adverse reactions.

More than One Action

Drugs can have both therapeutic (desirable) and adverse (undesirable) effects.
An adverse effect could, in some cases, be a therapeutic effect in another context.

Adverse Drug Reactions

Adverse drug reactions are unintended, potentially harmful responses to a drug.
These responses typically occur at usual therapeutic doses.

Categories of Adverse Drug Reactions

Toxic reaction: An exaggerated response to the drug's intended action, often dose-related.
Side effect: A secondary, unintended effect of a drug, not part of the desired action, often dose related and affecting non-target tissues.
Drug Allergy: An immune response to a drug, not dose-related or predictable; previously exposed patients may exhibit hypersensitivity reactions. Less than 5% of adverse reactions are allergies. Four types of reactions exist (ABCD).
Idiosyncratic reaction: A reaction that's neither a side effect nor an allergy; genetically-related and unusual.
Interference with natural defense mechanisms: A drug's impact on the body's natural defenses can result in adverse reactions.
Teratogenic effects: Agents that cause birth defects, developmental abnormalities during gestation.
Local effects: Reactions specific to the application site.
Drug interactions: The alteration of one drug's effect by another drug, food, or disease.

Toxic Reaction

An extension of the drug's pharmacological effect.
Dose-related.
Exaggerated response on target tissues.
Example: A hypoglycemic agent causing blood sugar to fall too low.

Side Effect

Not part of the intended therapeutic action.
Dose-related.
Drug acts on non-target tissues, causing undesirable effects.
Example: Ibuprofen causing an upset stomach.

Drug Allergy

Hypersensitivity response to a previously encountered drug.
Not dose-related or predictable in this type of reaction.
Acts as an antigen and reacts with antibodies in sensitized patients.

Type I Drug Allergy

Anaphylactic shock, a severe, life-threatening event.
Other symptoms include rhinitis, asthma, urticaria, dermatitis, hypotension, bronchospasm, laryngeal edema, and cardiac arrhythmias.
Often occurs within minutes of exposure. Can be triggered by local anesthetics and penicillins.

Type II: Cytotoxic/Cytolytic Drug Reaction

Antigen-antibody complexes attach to circulating blood cells, causing cell death.
Example: Penicillin-induced hemolytic anemia.

Type III: Immune Complex, Arthus, Serum Sickness

Clumps of antigen-antibody complexes deposit in the blood vessel walls.
Symptoms include serum sickness, urticarial skin eruptions, arthralgia, arthritis, lymphadenopathy, and fever.
Typically occurs 2-3 weeks post exposure.

Type IV: Delayed Hypersensitivity

Reactions are mediated by sensitized T-lymphocytes and macrophages, not antibodies.
Symptoms appear 2-3 days later.
Example: poison oak, cheap jewelry, autoimmune disease.

Idiosyncratic Reaction

Not a side effect or allergy.
Genetically related abnormal reaction.
Example: Eskimos metabolizing drugs faster than others.

Interference with Natural Defense Mechanisms

Drug's effect on the body's defenses.
Can result in adverse reactions.
Example: Prolonged corticosteroid use can decrease infection resistance.

Teratogenic Effect

Agents causing congenital malformations or developmental abnormalities.
Exposure during pregnancy can cause birth defects.
Example: Table 22.1.

Teratogenic Effect (continued)

No drug is absolutely safe
Safest drugs to use during pregnancy are: penicillin, erythromycin, and acetaminophen
Drugs contraindicated during pregnancy are: tetracycline, nonsteroidal anti-inflammatory agents, benzodiazepines, metronidazole, and thalidomine.

Local Effect

Reactions limited to the application site.
Injectable drugs can cause pain, irritation, and necrosis.
Drugs applied topically may also cause irritation.
Oral medications may cause gastrointestinal symptoms.

Drug Interactions

The effect of one drug is altered by another drug.
Types include drug-drug interaction, drug-food interaction, and drug-disease interaction.
Table 3-1.

Toxicological Evaluation of Drugs

Evaluating toxic effects of drugs, both on animals and humans.
Lethal does is the dose that kills 50% of the tested animals.
Median effective dose is the dose that produces a specific intensity of effect in 50% of the tested animals.
Therapeutic index.

Recognizing Adverse Effects

Patient education is critical.
Crucial to identify drugs being taken and when. The time from beginning therapy to the onset of symptoms is important for assessment.
Identifying the drug causing the adverse effect is key.

Dental Hygiene Considerations

Recognizing the difference between side effects, toxic effects, and allergic reactions.
Asking patients for information and assessing allergy history.
Educating patients about possible drug effects.
Assessing possible pregnancy to ensure appropriate medication choices.

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Description

Explore the complexities of adverse drug reactions in pharmacology. This quiz covers various types of adverse effects, including toxic reactions, side effects, and drug allergies. Test your understanding of how these reactions can impact drug therapy.