12 Questions
What type of medication is Diphenhydramine (Benadryl) classified as?
H1 blocker
What is the primary mechanism of action of anti-histamines in treating allergic reactions?
Blocking histamine receptors
What is a common side effect of anti-histamines?
Headache
What is a potential interaction of anti-histamines with sedatives and tranquilizers?
Increased risk of drowsiness
Which of the following anti-histamines is considered non-drowsy?
Loratadine (Claritin)
What is a less common side effect of anti-histamines?
Hallucinations
What is the primary function of H1 histamine receptors?
Allergic responses, smooth muscle contraction, and increased vascular permeability
What is the effect of histamine release on blood vessels during an allergic reaction?
Vasodilation and increased blood flow
What is the underlying cause of histamine intolerance?
Deficient diamine oxidase (DAO) enzyme or gastrointestinal disorders
What is the role of histamine in the regulation of gastric acid secretion?
Stimulating gastric acid secretion and increasing gut motility
What is the role of histamine in the brain?
Arousal and wakefulness, appetite regulation, sleep-wake cycle, and pain modulation
What is a potential consequence of imbalances in histamine levels or receptor function in the brain?
Increased risk of neurological disorders, such as ADHD, anxiety, and depression
Study Notes
Anti-Histamine Study Notes
Medication Interactions
- Anti-histamines can interact with:
- Sedatives and tranquilizers, increasing the risk of drowsiness
- Anticholinergic medications, increasing the risk of dry mouth, constipation, and urinary retention
- MAOI (monoamine oxidase inhibitors) antidepressants, increasing the risk of serotonin syndrome
Histamine Blockers
- Anti-histamines work by blocking histamine receptors (H1, H2, H3, H4) in the body
- H1 blockers:
- Diphenhydramine (Benadryl)
- Loratadine (Claritin)
- Cetirizine (Zyrtec)
- H2 blockers:
- Ranitidine (Zantac)
- Famotidine (Pepcid)
Allergic Reactions
- Anti-histamines are used to treat allergic reactions by:
- Reducing histamine release from mast cells
- Blocking histamine receptors, reducing symptoms such as itching, sneezing, and runny nose
Side Effects
- Common side effects of anti-histamines:
- Drowsiness
- Dizziness
- Dry mouth
- Headache
- Stomach upset
- Less common side effects:
- Confusion
- Hallucinations
- Seizures
Non-Drowsy Options
- Non-drowsy anti-histamines:
- Loratadine (Claritin)
- Cetirizine (Zyrtec)
- Fexofenadine (Allegra)
- Levocetirizine (Xyzal)
- These medications are designed to reduce the risk of drowsiness, but may still cause drowsiness in some individuals.
Learn about anti-histamine medications, their interactions, effects, and side effects. Understand how they work, their types, and non-drowsy options. A study guide for medical students and professionals.
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