Anti-emetics Flashcards
What are the 5 things that stimulate vomiting?
- Sight/smell/pain/emotion that directly stimulates the limbic system
- Motion stimulating CN 8
- Taste stimulating CN 7, 9, 10
- Vagal/visceral afferents from GI to CTZ (chemoreceptor trigger zone) and VC (vomiting center) directly
- Blood concentration of emetics/CSF stimulate CTZ
All of the stimuli for vomiting stimulate it where?
Vomiting center in the area postrema of the medulla
What drug makes you vomit? (not on CDL)
Tincture of ipecac (remember the Family guy?)
What are the 5 classes of drugs used to treat emesis?
- Anticholinergics
- Antihistamines
- Anti-dopaminergics
- Serotonin antagonists
- Misc. anti-emetics
How do the anti-histamines work?
H1 antagonists; older antihistamines that are also anticholinergics. Vestibular & vagal blockers (as opposed to anticholinergics which only block vagal stimulation)
Which anti-emesis drug is OTC for motion sickness?
Cyclizine
MOA & clinical use of Meclizine?
H1 antagonist; depresses hyperstimulation of labyrinth; used for vestibular disturbance (Vertigo & Menier’s dz)
What anti-dopaminergics are on the CDL?
- Chlorpromazine
- Droperidol
- Metoclopramide
Chlorpromazine MOA?
Centrally acting anticholinergic & anti-dopaminergic. Used for N/V and intractable hiccough
Droperidol MOA?
Blocks D2 in CTZ. Used for post-operative N/V
Metoclopramide MOA?
Used to prevent chemo induced N/V and post-op N/V. Stimulates gastric emptying
What are the serotonin antagonists on the CDL?
- Granisetron
2. Dolasetron
Serotonin antagonists MOA in general?
block 5-HT3 in stomach and SI. these organs stimulate CTZ/VC thru Vagus & nucleus tractus solitarius. They also block 5-HT3 in the CTZ. MOST EFFECTIVE ANTI-EMETICS! Effective alone but can be used w/ steroids & benzodiazapines
What stands out about Granisetron?
Very potent
What stands out about Dolasetron?
Longer half life than other 5-HT3 blockers.
Dolasetron lasts and lasts
What is the corticosteroid that can be given for anti-emesis?
Methyl prednisolone
Why is methyl prednisolone useful?
It increases the anti-emetic effect of other drugs and decreases the side effects of the other drugs (I guess b/c u can lower the dose of the other drug with the addition of the steroid).
Methyl prednisolone also has its own anti-emetic effect. Describe it
Decreases PG’s from chemo/radiation
MOA of Aprepitant?
Substance P/neurokinin 1 receptor antagonist.
Aprepitant is used for?
Given adjunct with chemo to prevent N/V
Unique things about Aprepitant? (3)
- Crosses BBB so acts centrally
- CYP3A4 metabolized
- Tmax= 4 hours. Half life = 10hrs
What benzodiazepine is on the CDL? MOA?
Lorazepam. Given adjunct with other anti-emetics prior to chemo (causes somnolence & amnesia that lasts hours).
**Lorazepam makes you too Lazy to vomit
What is the anticholinergic that treats vomiting? Specifically what type of vomiting does it treat?
Scopolamine- prophylaxis for motion sickness. Its the patch you put behind your ear
MOA of Scopolamine?
Vagal blocker; specifically blocks M1 activation and stimulation of CN VIII (which fires cholinergic stimulation to vomiting center in medulla)
AEs of Scopolamine?
Sedation, dry mouth, drowsiness
What anti-emesis drugs treat motion sickness?
Scopolamine, Cyclizine, Meclizine**
**Meclizine treats vestibular disturbance (Vertigo & Menier’s dz which cause a perceived motion sickness)
What is the treatment regimen for the anticipatory N/V that comes with chemo tx?
Give a serotonin antagonist + another drug (like methyl prednisolone, Lorazepam, Aprepitant, or D2 antagonist)
