Autacoids - Histamine

Question 1

Most important amine autacoids

Answer 1

Histamine & serotonin

Question 2

Ergot alkaloids have effects on _____ and _____

Answer 2

Serotonin receptors, smooth muscles

Question 3

Ergot alkaloids act on which organs.

Answer 3

CNS, pituitary, uterus, blood vessels

Question 4

Histamine is stored in which cell types?

Answer 4

Mast cells, enterochromaffin cells, gut, neurons

Question 5

How can histamine be detected in the body?

Answer 5

Level of Imidazole acetic acid in the urine

Question 6

Pathophysiologic role of Histamine

Answer 6

Seasonal rhinitis (hay fever), Urticaria, Angioneurotic edema, control of stomach acid secretion

Question 7

Modulates smooth muscle contraction, neurotransmitters and for vasodilation

Answer 7

H1

Question 8

Give H1 and H2’s signal transduction unit.

Answer 8

Gq/G11, Gq/G11, Gs (respectively)

Question 9

These histamine receptors act on Gi/Go subunits.

Answer 9

H3, H4

Question 10

All Histamine receptors except _____ can be found at the brain.

Answer 10

H4

Question 11

Give locations of each Histamine receptor.

Answer 11

H1: Heart, brain, mast cells
H2: Heart, brain, neutrophil, parietal cell
H3: Brain, PNS
H4: Blood cells (mast, eosino, monocyte)

Question 12

Give the physiological function of each Histamine receptor.

Answer 12

H1: smooth ms contraction, modulates neurotransmitters, vasodilate
H2: (+) gastric acid, leukocyte function
H3: CNS activity
H4: allergic reaction

Question 13

This H1 receptor antagonist has strong sedative effects and can pass BBB.

Answer 13

1st generation agents

Question 14

Give the characteristics of Second generation H1 receptor antagonists.

Answer 14

Metabolized by CYP3A4, less lipid soluble, less sedative (less CNS distribution)

Question 15

H1 receptor antagonists reach peak blood concentration in ___ hours and has a duration of action of ___ hours.

Answer 15

1-2, 4-6

Question 16

Which H1 receptor antagonist drug acts as an exception by having a longer duration of action?

Answer 16

Meclizine (Bonamine) (12-24 hours)

Question 17

H1 antagonist: ______ moiety; H2 antagonist: _________ ring

Answer 17

ethylamine, imidazole

Question 18

H1 receptor pharmacodynamics: _____ antagonism; mast cell stabilization at ____ doses

Answer 18

reversible competitive, low

Question 19

H1 receptor blockers effects on HR, blood vessels, blood pressure

Answer 19

increase (tachycardia), inhibits vasodilator effects (vasoconstrict)

Question 20

H1 receptor blockers affect the cortex (excites and depresses), chemoreceptor trigger zone and vomiting center (T/F).

Answer 20

TRUE

Question 21

H1 receptor blockers have an anesthetic-like action and is antipruritic to ______ (CNS/PNS).

Answer 21

PNS

Question 22

H1 receptor blockers are broncho______.

Answer 22

Bronchodilators

Question 23

Second generation H1 antagonists are used for _____ and ______.

Answer 23

Allergic rhinitis, chronic urticaria

Question 24

Which drug/s are best used for motion sickness and vestibular disturbances?

Answer 24

Scopolamine, certain 1st Generation H1 antagonists

Question 25

Which drug/s has/have the best effectiveness in treating motion sickness and induces sedation?

Answer 25

Diphenhydramine, Promethazine

Question 26

Which drug can treat motion sickness but is less sedating than diphenhydramine?

Answer 26

Piperazines (Meclizine)

Question 27

2nd Generation H1 Antagonists are more sedating and are more lipid soluble than 1st Generation.

Answer 27

FALSE

Question 28

Side effects of H1 receptor antagonists are anticholinergic in nature. (T/F)

Answer 28

FALSE (Antimuscarinic: dry mouth, blurred vision)

Question 29

2nd Generation H1 Antagonists are contraindicated with what 2 KINDS of drugs?

Answer 29

Antifungal (ketoconazole, itraconazole), macrolide antibiotics (erythromycin, azithromycin, clarithromycin)

Question 30

H1 antagonists when combined with drugs that depress the CNS produce additive effects. (T/F)

Answer 30

TRUE

Question 31

Ethanolamine used for allergies, produces marked sedation.

Answer 31

Hydroxyzine (Atarax) 15-100 mg

Question 32

Piperazine derivative ised as anti-motion sickness and produces slight sedation.

Answer 32

Cyclizine (Marezine) and Meclizine (Bonamine) 25-250 mg

Question 33

Alkylamines commonly used for "cold" medications. Produces slight sedation.

Answer 33

Chlorpheniarmine (Chlor-Trimeton) 4-8mg

Question 34

Phenothiazine derivative used as antiemetic, a-block, and produces marked sedation.

Answer 34

Promethazine (Phernergan) 10-25 mg

Question 35

Fexofenadine (Allegra) is a 2nd generation antihistamine which is given at what usual dose?

Answer 35

60mg

Question 36

Loratadine (Claritin) & Desloratadine (Clarinex) are longer acting antihistamines. (T/F)

Answer 36

TRUE

Question 37

H2 receptor antagonists are rapidly absorbed in the _____.

Answer 37

Intestine

Question 38

Cimetidine, ranitidine and famotidine undergoes first-pass hepatic metabolism, giving a 50% bioavailability. (T/F)

Answer 38

TRUE

Question 39

H2 antagonists exhibit what kind of inhibition?

Answer 39

Competitive

Question 40

H2 antagonists are (highly/not highly) selective and (do/do not) affect H1 or H3 receptors.

Answer 40

highly, do not

Question 41

H2 antagonists reduce bicarbonate secretion by histamine, gastrin and cholinomimetic agents. (T/F)

Answer 41

TRUE

Question 42

Give 2 diseases inhibited by H2 blockers.

Answer 42

GERD, gastric erosions and hemorrhage

Question 43

Diarrhea, headache, fatigue, myalgias, mental status changes, and constipation are common adverse effects of which blockers?

Answer 43

H2 blockers

Question 44

Which specific H2 blocker interferes with CYP450 metabolism pathways (CYP1A2, 2C9, 2D6, 3A4)?

Answer 44

Cimetidine

Question 45

Give 4 H2 blockers (Drugs) which can prevent GERD and stress ulcers.

Answer 45

Cimetidine, famotidine, ranitidine, nizatidine

Question 46

H3 blockers help correct sleep disorders, narcolepsy, obesity and cognitive and psychiatric disorders, and gastric hemorrhage. (T/F)

Answer 46

FALSE (No gastric hemorrhage)

Question 47

Tiprolisant is an ___ blocker that can reduce sleep cycles with narcolepsy.

Answer 47

H3