Week 9 Topical - Antihistamine/Antipruritic

Question 1

True or false:

Topical diphenhydramine can be safely used with oral/systemic diphenhydramine

Answer 1

False - increased risk for toxicity (delerium/psychosis)

Question 2

What is the MOA of topical diphenhydramine (benadryl)?

Answer 2

• Local H1 receptor antagonism (prevents histamine activation that leads to itching/edema)
• possible local anesthetic effect by decreasing nerve cell permeability to sodium

Question 3

True or false:

Topical diphenhydramine (benadryl) is indicated for treatment of chickenpox and measles

Answer 3

False - chickenpox and measles are contraindications to the use of this topical drug

Question 4

Use of topical diphenhydramine should be limited to no more than ______

Answer 4

7 days

increased risk for skin irritation/ADR

Question 5

What are indications for topical diphenhydramine?

Answer 5

Mild itching/edema from bug bites/stings or poison ivy/oak