Sketchy Pharm: Diphenhydramines

Question 1

Most of the body’s histamine is stored in __________.

Answer 1

mast cells and basophils

Question 2

What kind of receptors are H1 and H2?

Answer 2

H1: G(q) – think of Lisander with the Q-shaped dandelion (he’s about to get allergies, and that is H1)
H2: G(s) –think of the stomach with the two S-shaped handles

Question 3

H2 receptors, when stimulated, induce ______________.

Answer 3

gastric acid secretion

Question 4

H1 receptors, when stimulated from mast-cell histamine, induce _______________.

Answer 4

nasal and bronchial mucus secretion; bronchoconstriction on smooth muscle; and vasodilation with increased vascular permeability

Question 5

H1-blocking agents enter the _____________ to alleviate seasickness.

Answer 5

vestibular system

Question 6

__________-generation antihistamines easily enter the CNS.

Answer 6

First (where they bind H1)

Question 7

True or false: first-generation antihistamines block muscarinic channels in the CNS and PNS.

Answer 7

True (this is why they lead to some of the same side effects); they can thus also be used to treat motion sickness and the extrapyramidal effects of Parkinson’s by reestablishing the dopamine-choline balance

Question 8

Antihistamines can also lead to increased ____________ and _________ antagonism.

Answer 8

appetite (with weight gain); serotonin and alpha-1

Question 9

What are the three main 2nd-generation antihistamines?

Answer 9

Fexofenadine, cetirizine, and loratidine

Question 10

What are the first-generation antihistamines?

Answer 10

Diphenhydramine
Chlorpheniramine
Promethazine
Hydroxyzine
Meclizine