Pharm 16 Histamine, Serotonin & Ergot Alkaloids

Front 1

MOA of H1 receptor?

Back 1

IP3 and DAG-mediated smooth muscle effects, esp IgE induced. Bronchoconstriction and vasodilation (release of NO), increases vascular permeability

Front 2

MOA of H2 receptor?

Back 2

activates adenylyl cyclase to increase cAMP to mediate gastric acid secretion by parietal cells in stomach, stimulate heart, and reduce histamine release from mast cells

Front 3

highly sedating H1 blocker w/ significant autonomic receptor-blocking effects

Back 3

diphenhydramine

Front 4

newer 1st gen H1 blockers with less sedation and autonomic effects

Back 4

chlorpheniramine, cyclizine

Front 5

H1 blockers that are lipid insoluble and have less sedation and autonomic effects than 1st gens

Back 5

fexofenadine, loratadine, cetirizine

Front 6

H1 receptor blockers are more effective if given when?

Back 6

before histamine release occurs (do not affect histamine release from storage sites)

Front 7

in addition to blocking histamine effects, many 1st gen H1 blockers have what other effects?

Back 7

act as antimuscarinics/alpha blockers
some block serotonin receptors
most are sedating
some have anti-motion sickness effects

Front 8

major clinical use of H1 blockers?

Back 8

immediate-type allergic hypersensitivity reactions

Front 9

H1 blockers used as anti-motion sickness drugs (5)

Back 9

diphenhydramine, dimenhydrinate, cyclizine, meclizine, promethazine

Front 10

alpha blocking action of promethazine may cause what?

Back 10

orthostatic hypotension

Front 11

toxic effects of 1st gen H1 blockers?

Back 11

sedation, antimuscarinic effects (dry mouth, blurred vision)

Front 12

H1 blocker interaction with what other drugs can cause dangerously high plasma drug concentrations, precipitating lethal arrhythmias?

Back 12

CYP3A4 inhibitors, like azole antifungals

Front 13

antihistamines used to treat acid-peptic disease, gastric ulcer (4)

Back 13

cimetidine, ranitidine, famotidine, nizatidine

Front 14

major toxic effects of cimetidine?

Back 14

P450 inhibitor, reduces hepatic blood flow, antiandrogen effects (high dose)

Front 15

most serotonin agonists act at what receptor?

Back 15

5HT1d

Front 16

5HT1 receptors mediate inhibitory effects in the brain via _____?

Back 16

increased potassium conductance

Front 17

MOA of 5HT2 receptors?

Back 17

synaptic excitation in CNS and smooth muscle contraction via increased IP3, decreased potassium conductance, and decreased cAMP

Front 18

where are 5HT3 receptors found?

Back 18

in CNS, esp in chemoreceptive area/vomiting center, and in peripheral sensory and enteric nerves

Front 19

5HT1D agonists used in tx of acute migraine and cluster headaches

Back 19

sumatriptan, naratriptan

Front 20

5HT4 partial agonist used for tx of chronic constipation but has cardiovascular toxicity?

Back 20

Tegaserod

Front 21

irreversible 5HT2 receptor antagonist used in tx of carcinoid tumor?

Back 21

phenoxybenzamine

Front 22

competitive 5HT2 receptor antagonists used in tx of carcinoid tumor?

Back 22

Ketanserin, cyproheptadine

Front 23

serotonin antagonist used in tx of women w/ IBS w/ diarrhea?

Back 23

Alosetron (5HT3)

Front 24

serotonin antagonists used as antiemetics after cancer chemotherapy?

Back 24

Ondansetron, granisetron, dolasetron (5HT3)

Front 25

poorly selective serotonin antagonists with alpha blocking and/or H1 blocking effects?

Back 25

ketanserin, phenoxybenzamine, cyproheptadine

Front 26

toxic effects of selective 5HT3 antagonists?

Back 26

diarrhea, headache

Front 27

this serotonin blocker is associated with QRS and QTc prolongation

Back 27

Dolasetron

Front 28

Serious toxic effect of Alosetron?

Back 28

significant constipation

Front 29

ergot alkaloids have effects on what receptors?

Back 29

alpha adrenoceptors and 5HT receptors, some are also agonists at dopamine receptor

Front 30

overdose of these drugs can cause ischemia and gangrene of the limbs

Back 30

ergot alkaloids, esp ergotamine

Front 31

used to produce uterine contraction after delivery of the placenta to stop bleeding

Back 31

ergot alkaloids, esp ergonovine

Front 32

ergot alkaloids used as dopamine D2 receptor agonists to stop prolactin secretion

Back 32

Bromocriptine, Pergolide

Front 33

primary clinical use of ergotamine?

Back 33

migraine

Front 34

ergot alkaloids used in tx of parkinson's dz?

Back 34

bromocriptine, pergolide

Front 35

antidote for severe prolonged vasoconstriction d/t ergot overdose?

Back 35

nitroprusside

Front 36

fibroplasia leading to hydronephrosis or cardiac valvular and conduction system malfxn is d/t prolonged use of what?

Back 36

ergot alkaloids