Antiemetics Flashcards Preview

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Flashcards in Antiemetics Deck (20):
0

Antihistamine - as a group side effects seen

CNS: confusion, dizziness, tinnitus, incoordination, tremors

Anti-muscarinic effects from antihistamines : sedation, urinary retention, blurred vision, exacerbation of narrow angle glaucoma.

1

Location of histamine receptors with respect to antihistamines working as an antiemetic

Inner ear (motion) -> Cerebellum(H1) -> medulla ( emetic center)

Pharynx (gagging)->glossopharyngeal and trigem afferents -> solitary tract nucleus(H1) -> medulla

3

Scopolamine

Anticholinergic- block at the cerebellum . Info from inner ear and also solitary tract nucleus


Used for motion sickness , post op n/v , no role in chemo induced nausea

Side effects: dry mouth, urinary retention, blurred vision, exacerbation narrow angle glaucoma

4

Promethazine

Antihistamine with wek anti-d2 activity ( motion)
maybe be more effective than cyclizine and Meclizine

6

5-HT3 receptor antagonists blocks what peripherally and centrally

Peripheral - 5-HT released for enterochromaffin of the sm intestine in response to chemo agents that stim vagal efferents

Central : 5-ht receptors in the solitary tract nucleus and area postrema

8

Prochloroperazine

Dopamine receptor antagonist. D2 reports in the chemo receptor trigger zone (area postrema)

Also has some antihistamine and anticholinergic properties

9

Glucocorticoid and ant inflammatory agents

Used in treatment of nausea in pts with wide spread cancer
- may suppress peritumoral inflammation and prostaglandin production

11

Meclizine

Antihistamine

Used exclusively for motion sickness

12

Dopamine receptor antagonist side effects

Sedation, dystonia, orthostatic hypotension , extrapyramidal symptoms, impaired thermoregulation

13

Benzodiazepines

Not effect alone
Cause : sedation, amnesic and anti anxiety properties. Av reduce anticipatory nausea and vomititng

14

Ondansetron

5-HT3 receptor antagonist
- drug persits even aft serum levels have decreased ( take once a day)
- metabolized in the liver by p450 ( decrease dose with liver probs)
-

SE: constipation, diarrhea, headache, minor electrocardiographic changes

Use: chemo,upper abdominal irradiation, hyperemesis in pregnancy

15

Aprepitant

Substance P receptor antagonist

- tachykinin family
- present in vagal afferents inner acting the solitary tract nucleus
- p450

16

Migraine use

Metoclopramide or procholorperazine ( dopamine antagonist )
If nausea alone use adjunct 5-ht antagonist

17

Vestibular use

Antihistamines or anticholinergics

18

Pregnancy use

Nausea : Ginger, vit b6
Hyperemesis: promethazine , 5-HT antagonist , methylprednisolone

19

Gastroenteritis use

First line: da antagonist ( cheaper)
Second lien: 5-HT antagonist

20

Metoclopramide

Dopamine receptor antagonist - area postrema

Pro kinetic agent - coordinated contractions of GI tract that enhance transit
- blocks 5-HT3 receptors centrally and on vagus
-sensitizes muscarinic receptors
- agonist at 5-HT4

**greatest utility is it's ability to ameliorate the no nausea and vomiting accompany GI dysmotility syndromes

21

Dronabinol

Cannabinoid
- stim CB1 type cannabinoid receptor

CNS effects: sympathomimetic activity, marijuana high, paranoid rxn.

Use : cancer chemo, stimulates appetite

22

Cyclizine

Antihistamine ( H1) and some anti-muscarinic activity

Used exclusively for motion sickness

23

Diphenhydramine

Antihistamine ( motion)
maybe be more effective than cyclizine and Meclizine