Antihistamines

Question 1

What is the primary action of antihistamines?

Answer 1

Compete with histamine for receptor sites and prevent a histamine response

By blocking the H1 receptor sites, nasopharyngeal secretions and itching decrease.

Question 2

Name the two groups of antihistamines.

Answer 2

• First-generation antihistamines
• Second-generation antihistamines

Each group has distinct characteristics and side effects.

Question 3

What are the common side effects of first-generation antihistamines?

Answer 3

• Drowsiness
• Dry mouth
• Dizziness
• Fatigue
• Blurred vision
• Disturbed coordination
• Urine retention

These side effects are due to their action on muscarinic and histamine1 receptors.

Question 4

True or false: Second-generation antihistamines usually cause more drowsiness than first-generation antihistamines.

Answer 4

FALSE

Second-generation antihistamines typically have less drowsiness and fewer anticholinergic symptoms.

Question 5

Fill in the blank: Second-generation antihistamines are usually _______ acting.

Answer 5

longer

This characteristic contributes to their effectiveness in managing allergic symptoms.