Biogenic Amines

Question 1

What is histamine synthesized from

Answer 1

Histadine (by histadine decarboxylase)

Question 2

Histamines mechanism of action

Answer 2

Binds to specific histamine receptors

Question 3

Vascular histamine effects

Answer 3

Constricts larger vessels, dilates smaller vessels - local edema

Question 4

What is the “triple response”

Answer 4

Central red spot, flare, wheal

Question 5

Neuronal histamine effects

Answer 5

Stimulates sensory neurons - itching, pain

CNS: increases alertness

Question 6

Smooth muscle histamine effects

Answer 6

Constricts bronchioles and intestinal muscle - diarrhea

Question 7

Exocrine histamine effects

Answer 7

Stimulates bronchial, salivary and digestive secretions

Question 8

Mechanism of action of antihistamine action

Answer 8

Blocks histamine receptor

Question 9

H1 blocker effect of CNS

Answer 9

Sedative (enhanced in children and elderly)
Anti nausea
Anti emetic

Question 10

How do H1 blockers affect mucous membranes

Answer 10

Dry membranes due to muscarinic effects

Question 11

H1 blocker effect on peripheral nervous system

Answer 11

Acts as local anesthetic

Question 12

How do H1 blockers affect bronchiole smooth muscle

Answer 12

Dilates it due to inhibition of interleukins and other inflammatory mediators

Question 13

H2 blocker effect on gastric secretion

Answer 13

Decrease acid secretion because histamine is required to stimulate acid secretion from parietal cells

Question 14

What are 4 therapeutic indications for 1st generation H1 antihistamines

Answer 14

Treatment of allergic responses, anti emetic, anti nauseant, sedatives

Question 15

What 3 allergic responses do 1st generation H1 antihistamines treat

Answer 15

Dermatoses - urticaria (itching from insect stings and bites)
Allergic rhinitis
Allergic conjunctivitis - decreases congestion and sneezing

Question 16

1st generation H1 blocker mechanism

Answer 16

Can act on peripheral and central H1 receptors

Question 17

Why can 1st generation H1 blockers enter CNS

Answer 17

They are nonionized

Question 18

Name 6 1st generation H1 blockers

Answer 18

Diphenhydramine
Clesmastine
Chlorpheniramine
Hydroxyzine
Promethazine
Tripelennamine

Question 19

Diphenhydramine

Answer 19

Sedative and motion sickness

Question 20

Clemestine

Answer 20

Primarily for motion sickness

Question 21

Chlorpheniramine

Answer 21

Not a sedative

Question 22

Hydrozyzine

Answer 22

Sedative and anti itch

Question 23

Promethazine

Answer 23

Strong sedative and anti emetic

Question 24

Tripelennamine

Answer 24

Sedative with local anesthetic effects

Question 25

2nd generation H1 blocker effects

Answer 25

Fewer CNS effects - ionized in blood | Don't cause drowsiness

Question 26

Is therapeutic index for H1 blockers high or low

Answer 26

High

Question 27

Toxicity of H1 blockers

Answer 27

Interact with other CNS depressants

Question 28

Toxicity of all H1 blockers

Answer 28

Antimuscarinic effects: dry mouth, blurred vision, constipatoin

Question 29

Why can't H2 blockers get in CNS

Answer 29

Can't cross blood brain barrier

Question 30

4 H2 blockers

Answer 30

Cimetidine, ranitidine, famotidine, nizatidine

Question 31

Cimetidine effect

Answer 31

Anti androgen effect

Question 32

What is 5HT synthesized from

Answer 32

Tryptophan

Question 33

Where is 5HT found

Answer 33

Enterchromaffin cells of the gut

Question 34

5HT mechanism

Answer 34

7 different 5HT receptors

Question 35

Physiological effects of 5HT

Answer 35

Smooth muscle constriction Itching, pain Central neurotransmission Causes nausea

Question 36

What is carcinoid syndrome

Answer 36

Tumor of enterchromaffin cells leads to too much 5HT

Question 37

Symptoms of carcinoid syndrome

Answer 37

Diarrhea Bronchospasm Skin flushing Fibrosis of heart valves

Question 38

Why does carcinoid syndrome have no CNS effects

Answer 38

Enterchromaffin cells are produced peripherally

Question 39

Cause of migraine

Answer 39

Hemicrania over time

Question 40

What happens to blood vessels during migraine

Answer 40

Strong dilation of blood vessels in dura and pia mater

Question 41

Side effects of migraine

Answer 41

Inflammation, swelling and throbbing pain

Question 42

What happens to 5HT when taking drugs for migraine

Answer 42

5HT is inferred by effect of the drugs

Question 43

What kind of migraine agents alter 5HT system

Answer 43

Agonists or partial agonists of 5HT receptor

Question 44

What can migraine agents cause

Answer 44

Vasoconstriction

Question 45

Group of agents that act on 5HT receptors

Answer 45

"TRIPTANs"

Question 46

Sumatriptan mechanism of action

Answer 46

5HT receptor agonist

Question 47

Sumatriptan mode of administration

Answer 47

Orally, nasal spray or injection

Question 48

What shouldn't you use when taking sumatriptan

Answer 48

MAO inhibitors have synergistic effect leads to 5HT syndrome - hyperthermia and muscle twitching