Antiemetics Flashcards

1
Q

Where is the vomiting center that consists of the nucleus of tractus solitarius and parts of the reticular formation?***

A

Emesis controlled by vomiting center which lies in the (medulla oblongata)*** which consists of the nucleus of the tractus solitarius and parts of the reticular formation.

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2
Q

What detects noxious chemicals in the blood stream that is cephalad to the vomiting center?***

A

Cephalad to vomiting center is the CRTZ (Chemoreceptor trigger zone)*** which detects noxious chemicals in blood stream

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3
Q

Which cranial nerves sends signals through the vagal parasympathetic fibers upon activation of the vomiting centers?**

A

Activation of the vomiting center sends signals via (cranial nerves V, VII, IX, X, and XII)*** through vagal parasympathetic fibers and the sympathetic chain to the skeletal muscle through alpha motor neurons

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4
Q

What six receptors will stimulate efferent signals via cranial nerves to the vomiting center? ***

A
Dopamine
Serotonin
Substance P
Acetylcholine
GABA
Cannabinoids
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5
Q

Where is the exact location of the Chemoreceptor trigger zone (CTZ)?**

A

At the base of Fourth ventricle in area of Postrema*****

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6
Q

What is makes the Chemoreceptor trigger zone (CTZ) unique? ***

A

Very vascular and lacks blood brain barrier.**
Because its location and exposure it can be directly stimulated by toxins, metabolites, and drugs that circulate in the blood and cerebrospinal fluid.

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7
Q

How does scopolamine work? What receptors?***

A

Competitive antagonist of AcH at (muscarinic receptors) and the MOST effective single agent for prevention of motion

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8
Q

What class of drug is scopolamine?

A

Anti cholinergics

Acetylcholine involved in integrating sensory stimuli in the vestibular nuclei and transmitting expected sensory information to the cerebellum.

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9
Q

Does atropine cross the BBB?**

A

Yes

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10
Q

What is the exact MOA of Scopolamine??***

A

MOA- blocks transmission to the medulla due to overstimulation of vestibular apparatus of the inner ear

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11
Q

Where does Metocolpraminde directly effect? **

A

CTZ

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12
Q

Does Metoclopramide (Reglan) cross the BBB?

A

Yes

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13
Q

What other effects does Metoclopramide (Reglan) have?

A

Other than effecting the CTZ it also has antidopaminergic effects

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14
Q

How does Midazolam work on the CTZ?***

A

May decrease synthesis and release of dopamine within the CRTZ*

GABA Agonist

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15
Q

What is the MOA of Midazolam??

A

GABA receptor mediated reduction of dopamine and 5HT3 receptor activity in the CTZ

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16
Q

What is the black box warning for Droperidol?

A

black box warning prolonged QT syndrome*

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17
Q

What class of drug is Droperidol?

A

Dopamine Antagonists

Butyrophenones

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18
Q

Which drug is considered an efficient rescue drug for PONV? Droperidol or Haloperidol?

A

Droperidol

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19
Q

Which drug is an antiemetic when used in low doses and used in Psych with high doses?

A

Haloperidol (Haldol)

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20
Q

What is the adult dose for Droperidol (inapsine)?**

A

Adults 0.625-1.25 mg

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21
Q

What is the peds dose for Droperidol (Inapsine)?***

A

Peds 50-75 mcg/kg

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22
Q

How does Droperidol (Inapsine) work?***

A

Binds to D2 receptors/antagonizes; also alpha-blocker

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23
Q

Why should you be cautious with giving Metoclopramide (Reglan) with patients that receive Succinylcholine?

A

Inhibits plasma cholinesterase, so action of succinylcholine may be prolonged*

24
Q

If someone is taking an MAOI’s or TCA, which antiemetic should you not give to this person?

A

Metoclopramide (Reglan)

25
Q

What is the proposed MOA for Dexamethasone?**

A

Proposed to inhibit prostaglandin synthesis and control endorphin release

26
Q

Which receptor does Dexamethasone work on?

A

20 to 30 times binding affinity for cortisol receptors

27
Q

What is the dose for Dexamethasone (Decadron)?***

A

Dose 4-10 mg for adults. Minimum 5 mg effective prophylactic dose needed*****

28
Q

What class is Odansetron (Zofran)?

A

Selective serotonin receptor antagonists

29
Q

What is the adult dose for Odansertron (Zofran)?***

A

Dose 4-8 mg IV over 2-5 min

30
Q

What is the peds dose for Odansertron (Zofran)?**

A

Peds >2 yrs: 0.05-0.15 mg/kg (max 4 mg)****

31
Q

What is the adult dose for Dolasetron (Anzemet)?**

A

Dose 12.5 mg IV 15 min before end of anesthesia

32
Q

What is the peds dose for Dolasetron (Anzemet)?**

A

Peds: 0.35mg/kg IV**

33
Q

What receptor does Tropisetron work on?

A

Highly selective 5-HT3 receptor

34
Q

What receptor does Granisetron and Dolasertron work on?

A

Highly selective 5-HT3 receptor

35
Q

How does Palonosetron work?

A

Cross talks between 5- HT3 and NK1k receptor pathway

36
Q

Nonspecific antihistamines acting on H1 receptors include:

A

Diphenhydramine (Benadryl)
Dimenhyrinate (Dramamine)
Cyclazine
Prochlorperazine-Rescue drug

37
Q

How does Diphenhydramine (Benadryl) work?

A

H1 receptor & inositol phospholipid invokes smooth muscle contraction in the GI tract

38
Q

What class is Aprepitant?

A

First and only FDA approved NK1 Receptor Agonist

Has the greatest efficacy than any other intervention*

39
Q

Does Aprepitant cross the BBB?

A

Yes

40
Q

What are NK1 receptors?

A

NK1 receptors are G protein- coupled receptors found in both the central and peripheral nervous system.

41
Q

Where are NK1 receptors found?

A

NK1 receptors are found in the GI tract, and also in high concentrations in brainstem nuclei, nucleus tractus solitarius, and area postrema( regulation of vomiting reflex).

42
Q

What is the does of Aprepitant (Emend)?

A

Dose 40 mg PO 3 hr before induction**

43
Q

How does Apreitant (Emend) work?

A

Blocks substance P from attaching to neurokinin receptor

Substance P in GI tract & CNS areas involved in vomiting reflex

44
Q

How does Propofol work?

A

Potentiate GABA which is inhibitory

45
Q

What is the dose for ephedrine?**

A

5-10 mg IV q 5-10 min; q 3-4 hr max 150 mg in 24hr**

Peds: 3mg/kg over 24 hr*****

46
Q

What is the dose for Dronabinol (marinol)?**

A

Dose 2.5 mg BID***

47
Q

How do antacids work?

A

Antacids are drugs that neutralize (remove hydrogen ions) from gastric contents or decrease the secretion of hydrogen chloride into the stomach.

48
Q

How does Citric acid & Sodium citrate (Bicitra)

work?

A
  • -Mixes with gastric fluid
  • -Rapidly buffers gastric fluid
  • -Raises gastric pH
  • –Passes through the stomach into small intestine to be absorbed into bloodstream
  • -Metabolized to sodium bicarb which raises gastric pH
  • -Sodium bicarb eliminated in urine
49
Q

What is Milk Alkali syndrome??**

A

Increase urine and gastric volume pH causes the following

Milk alkali syndrome *****: increase Ca, BUN, Creatinine, systemic alkalosis due to large amounts of Ca carbonate and >1L of milk per day

50
Q

Do H1 Receptor Antagonists have Possible tachyphylaxis

A

YES

51
Q

What is the dose for Cimetidine (tagemet)?***

A

300 mg IV Q 6hr*****

52
Q

What is the dose for Famotidine (Pepcid)?**

A

Dose 20-40 mg****

53
Q

How does Famotidine (Pepcid) work?

A

Highly competitive H2 antagonist

54
Q

What is the dose for metoclopramide?**

A

10 to 20 mg IV

55
Q

How does Metoclopramide (Reglan) work???** (???)

A

Selective cholinergic stimulation of the GI tract
EPS
Stimulates Prolactin
Effect CTZ contributes to antiemetic effect (???)