Allergy and Histamine Quiz

Questions and Answers

What is the effect of histamine on smooth muscles?

Relaxation of smooth muscles

Contraction of smooth muscles (correct)

Increased permeability of smooth muscles

No effect on smooth muscles

Which of the following is NOT a vascular effect of histamine?

Erythema in skin

Dilation of capillaries

Vasoconstriction (correct)

Leaky capillaries

What is a common side effect of 1st generation antihistamines?

Urinary retention

Dry mouth (correct)

Tachycardia

Hypertension

What is an advantage of 2nd generation antihistamines?

They are more selective for peripheral H1-receptors Signup and view all the answers

Which of the following is a less common side effect of antihistamines?

Rapid heartbeat Signup and view all the answers

What is the mechanism of action of antihistamines?

Blockage of H1-receptors Signup and view all the answers

Which of the following is NOT an indication for antihistamines?

Hypertension Signup and view all the answers

What is the effect of histamine on the heart?

Rapid heartbeat Signup and view all the answers

What is the primary target of allergies?

The immune system Signup and view all the answers

What is the term for a severe, life-threatening allergic reaction?

Anaphylaxis Signup and view all the answers

What is the primary mechanism of action of antihistamines?

Blockage of histamine receptors Signup and view all the answers

What is a common side effect of antihistamines?

Drowsiness Signup and view all the answers

What is the primary function of the scribe in the terminology exercise?

To write the definition of the term on Nearpod Signup and view all the answers

In the disease support meeting, what is the focus of the student presentations?

The symptoms and treatment of the disease Signup and view all the answers

What is the purpose of the terminology exercise in groups?

To encourage teamwork and collaboration Signup and view all the answers

What will be released after the class according to the lecture notes?

Answers to the terminology exercise Signup and view all the answers

What is the mechanism of action of Cromolyn Sodium?

Blocks the release of histamine from mast cells Signup and view all the answers

Which of the following antihistamines has the highest potential for CNS stimulation?

Chlorpheniramine Signup and view all the answers

What is the common side effect of Ethanolamines?

Sedation Signup and view all the answers

Which of the following is NOT a side effect of Phenothiazines?

CNS stimulation Signup and view all the answers

What is the primary use of Hydroxyzine?

Puritis/urticaria related reactions Signup and view all the answers

What is the indication for Cromolyn Sodium in food allergies?

Prophylactic Signup and view all the answers

Which of the following is NOT a brand name of Cromolyn Sodium?

Diphenhydramine Signup and view all the answers

What is the primary mechanism of action of Mast Cell Stabilizers?

Preventing the release of histamine from mast cells Signup and view all the answers

Study Notes

Allergens and Antibodies

An allergen is a substance that causes an allergic reaction
An antigen is a substance that triggers an immune response
An antibody is a protein produced by the body to fight against an antigen

Allergy Symptoms

Rhinitis: inflammation of the nasal passages
Urticaria: itchy, raised patches on the skin
Xerostomia: dry mouth
Anaphylaxis: a severe, life-threatening allergic reaction

Histamine

Histamine is a chemical mediator released by mast cells during an allergic reaction
Histamine causes:
- Vasodilation and increased permeability of blood vessels, leading to hypotension and fluid leakage
- Contraction of smooth muscles, leading to bronchoconstriction and gut cramps
- Rapid heart rate and arrhythmias

Antihistamines

Antihistamines are medications that counteract the effects of histamine
Indications for antihistamines:
- Acute allergic reactions
- Rhinitis, dermatitis, itchy eyes, scratchy throat, and urticaria
- Dry nasal secretions
- Sedation and sleep aids
- Reduction of nausea and vomiting, including motion sickness

First Generation Antihistamines

Sedating effects
Anticholinergic effects
Examples:
- Ethanolamines: most sedating, highest anticholinergic effects (e.g., Dimenhydrinate, Diphenhydramine)
- Alkylamines: highest potential for CNS stimulation, medium for epigastric distress (e.g., Chlorpheniramine)
- Phenothiazines: high anticholinergic effects, moderate sedation (e.g., Promethazine)
- Other first-generation antihistamines: Hydroxyzine

Second Generation Antihistamines

Less sedating
Less anticholinergic effects
Examples:
- Cetirizine
- Fexofenadine
- Loratadine
- Desloratadine

Antiallergic Agents

Cromolyn Sodium: prevents release of histamine through degranulation of mast cells
Mechanism of action: mast cell stabilizer
Indications:
- Prophylactic in chronic bronchial asthma, allergic rhinitis, food allergies, and allergic conjunctivitis
- Dosage forms and strengths: Nalcrom, Opticrom, Alocril

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Description

This quiz covers concepts related to allergy, histamine, and its effects on the human body, including vascular effects and various types of allergic reactions.