Anti-Emetics Drugs Flashcards
Examples of Serotonin Receptor Antagonist
Ondansetron
Palonsetron
Dolasetron
What kind of receptors are serotonin Receptor Antagonist
5HT3 receptors
Na/K gated channels found in CNS/PNS
What do serontonin receptor antagonist inhibit
central and peripheral stimulation of 5-HT3 receptors
Where are serontonin 5HT3 receptors located
CTZ
afferent fibers of vagus nerve in GI tract/CNS
+ of Serontonin Receptor Antagonist
effective do not cause sedation and well tolerated
when are Serotonin receptor antagonist administered
end of surgery
Side effects of serotonin receptor antagonist
headache, prolonged QT interval
PO Dose of Ondansetron
4 or 8mg
for PONV prophylaxis 16mg PO x1 hour prior to induction of anesthesia
IV Dose of Ondansetron
4mg single dose
0.1mg/kg if less the 40kg
Half life of Ondansetron
4 hours
Onset of Ondansetron
30 mins
Peak Plasma of Ondansetron
immediately
Bioavailability of Ondanestron
60%
How protein bound is Ondanestron
70-76%
Where is ondanestron metabolized?
liver by CYP3A4, CYP1A2, CYPD6
extensive metabolism in liver by hydroxylation and conjugation CYP450
less then 5% metabolized in kidneys (no renal dose adjustment)
Elimination 1/2 life of Ondansetron
3-7 hours
Excretion of Ondansetron
urine
feces
What will decrease clearance of Ondanestron
severe hepatic impairment due to increase in plasma 1/2 life
Side effects of Ondansetron
headache, dizziness, diarrhea, constipation, prolonged QTc
Palonosetron is
second generation serotonin antagonist
most selective- greater affinity for serontonin receptor
Palonosetron is one of the most effective treatments for
chemotherapy induced N/V and PONV
Half life of Palonosetron
40 hours (therapeutic effects for 72 hours)
Palonosetron dosing for PONV
0.75mg
Palonosetron dosing for chemo-induced N/V
0.25mg
Excretion of Palonosetron
more then 80% excreted in urine over 6 days and 1/2 amount unchanged
Special considerations for palonosetron
no doseage adjustments for elderly, renal or hepatic patients
no safety/efficacy data in patients <18 years of age
MOA of Dolasetron
reduce activity of vagus nerve to limit activation of the vomitting center in medulla oblongata
Dose of Dolasetron
12.6mg IV
DOA of Dolasetron
4-9 hours
Protein binding of Dolasetron
69-77%
Elimination 1/2 time of Dolasetron
8.1 hours
Where is dolasetron eliminated
liver (CYP450) kidneys
Onset of dolasetron
immediate
Peak Plasma of dolasetron
36 minutes
When is the best time to give dolasetron
15 minutes before the end of a case
Single dose of dolasteron
single oral dose 100mg 102 hours preop is effective
Adverse effects of dolasteron
headache, dizziness, constipation, potential for QT prolongation
How is dolasteron excreted
urine/feces
Dosing of Granisetron (kytril)
0.35-3 mg IV at end of surgery
Granisetron is common for
patients receiving chemotherapy and radiation
Half life of granisetron
3-14 hours
Bioavailbility of Graniestron
60%
Protein binding of graniestron
64%
Excretion of graniestron
renal and fecal
Adverse effects of granisetron
headache, dizziness, and constipation
Dopamine receptor antagonist
D2 receptors in GI tract sends signals to CNS to induce nausea and vomiting in vomiting center
Dopamine receptor antagonist are contraindicated in
parkinson’s disease
Side effects of dopamine receptor antagonist
extrapyramidal side effects
Dopamine Receptor antagonists are also known as
butyrophenone class
MOA of Droperidol
blocks dopamine receptors that contribute to development of PONV
Properties of Droperidol
anxiolytic, sedative, hypnotic and antiemetic properties
Dose of Droperidol
0.625-1.25mg IV (SLOW) or IM
Onset of Droperidol
3-10 minutes
Peak of Droperidol
30 minutes
DOA of droperidol
2-4 hours
Where is droperidol metabolized
lver
Excretion of droperidol
urine (unchanged) and feces
Unwanted side effect of Droperidol
qt prolongation
Dose of Droperidol effective at reducing vomiting
10-20mcg/kg
What dose of droperidol is superioir to metoclopramide PO in reducing PONV
20mcg/kg immediately after induction
20 mcg/kg of droperidol causes
prolonged sedation
High dose of droperidol (50-75mg/kg) causes
increased side effects: anxiety, dizziness, drowsiness, hypotension, extrapyramidal side effects
Droperidol requires
12 Lead EKG of patients 2-3 hours after administration
Prochlorperazine class
Phenothiazine
Anti-psychotic/antiemetic
MOA of prochlorperazine
affects multiple receptros
histaminergic, dopaminergic (D2 blockade), muscarinic
Prochlorperazine is used for
PONV prophylaxis
Dose of Prochlorperazine
5-10mg IM/IV before induction
DOA of Prochlorperazine
3-4 hours
Protein Binding of Prochlorperazine
91-99%
Peak onset Prochlorperazine
2-4 hours
Prochlorperazine is primarily metabolized by
liver (CYP2D6/CYP3A4)
Prochlorperazine elimination half life
6-10 hours (IV)
Excretion of Prochlorperazine
biliary inactive metabolites in urine
Side effects of Prochlorperazine
extrapyramidal and anticholinergic side effects
sedation, blurred vision, hypotension, dizziness, neuroleptic malignant, syndrome, restlessness and dystonia
Benzamide
Metoclopramide
MOA of Metoclopramide
centrally acting dopamine receptor antagonist in CTZ/vomiting center (peripherally acting as cholinomimetic in GI tract (facilitates Ach transmission at muscarinic receptors)
Metoclopramide will
increase LES tone, speeds gastric emptying time, lowers gastric fluid volume
Metoclopramide is effective for
gastroparesis, GERD, aspiration pneumonia prophylaxiss
Dose of Metoclopramide
10 mg IV (range 5-20mg) or 0.1-0.25mg/kg IV q6h
Metoclopramide must be administered
slowly over 1-2 minutes, if not abdominal cramping
studies show that Metoclopramide is
ineffective at lower doses, unless used in combination with other anti-emetics
Advantage of Metoclopramide
lack of sedative properties
Onset of Metoclopramide
3-4 minutes IV
Peak of Metoclopramide
1-2 hours
DOA of Metoclopramide
1-2 hours
Metabolism of Metoclopramide
liver
Elimination of Metoclopramide
renal excretion
elimination 1/2 life: 5-6 hours
adverse effects of Metoclopramide
extrapyramidal side effects
Metoclopramide C/A in
parkinson’s disease, seziure, GI obstruction and pheochromocytoma
Haloperidol belongs to what drug class
butyrophenone
Dose of Haloperidol
0.5-2mg
Is haloperidol approved by FDA for anti-emetic
no
When do you administer Haloperidol
beginning or end of surgery
Amisulpride is
a D2 adn D3 receptor antagonist
Dose of Amisulpride
5-10mg IV
Side effects of Amisulpride
mild increase in prolactin level
What drug is not associated with sedation, EP or QTc prolongation
amisulpride
Dose of perphenazine
5mg IV
What is perphenazine
atypical antipyschotic and dopamine receptor antagonist
Neurokinin 1 receptor antagonist
found in nucleus of solitary tract and regulate visceral function
provide antemetic activity by suppressing activity at NTS
Aprepitant (Emend)
neurokinin 1 receptor antagonist
MOA of aprepitant
inhibit substance P at central and peripheral receptors
Does aprepitant have sedative effects?
no
Long half life of aprepitant
9-13hours
Dose of aprepitant
40-80mg PO preop
Aprepitant is recommended for
high risk nonpregnant patients
Metabolism of aprepitant
liver
Bioavailability of Aprepitant
60-65%
Protein binding of aprepitant
> 95%
Excretion of aprepitant
feces and urine
adverse effects of aprepitant
fatigue, dizziness, hypoesthesia, disorientation, N/D, anorexia, constipation, diarrhea, dyspepsia, heartburn, ab pain, gastritis, perforating duodenal ulcer, hiccups
When administer dexamethasone + aprepitant
reduce dose by 1/2 to maintain dexamethasone plasma concentrations
Histamine-receptor Antagonist
dramamine dimenhydrinate
Promethazine
MOA of Dimenhydrinate
H1 antagonist competes with histamine at H1 receptor sites in GI tract, blood vessels and respiratory tract; blocks CTZ, depresses labyrinthine function and vestibular stimulation
Adverse effects of dimenhydrinate
drowsiness, urinary retention, dry mouth, blurred vision, extrapyramidal effects, commonly causes sedation
Dose of dimenhydrinate
50-100mg IV/IM q4h
Max dose of Dramamine
100mg 4hours
onset of dramamine
immediate
duration of dramamine
4-6 hours
metabolism of dramamine
liver
excretion of dramamine
metabolites excreted in urine
MOA of phenergan
Antihistamine (H1) antagonist and anticholinergic/ muscarinic blocking effects responsible for antiemetic properties
Dose of Promethazine
12.25mg q4-6h
DOA of promethazine
4-6 hours
Metabolism of Promethazine
hepatic (glucuronidation and sulfoxidation)
Elimination of Promethazine
kidney/biliary
Elimination 1/2 life of promethazine
10-19 hours
bioavailibility and protein binding of promethazine
88% and 93%
Common side effects of Promethazine
confusion, drowsiness, dry mouth, constipation (no for patient >65yrs)
significant sedation
MOA of scopolamine
muscarinic antagonist
inhibits action of ach at parasympathetic sites in smooth muscle, CNS and secretory glands
block communication between nerves of vestibule and vomit center in brainC
Scopolamine structure and solubility
tertiary amine
lipid soluble
Side effects of scopolamine
cerebral depression, sedation and amnesia
CNS side efffcts
Anticholinergic posioning
agitation delirium dry mouth tachycardia, impaired vision hallucinations unconciousness
Treatment for anticholinergic OD
physostigimine 0.01-0.03mg/kg IV repeat 15-30 mins
Scopolamine C/a in pateint
closed angle glaucoma
Dose of Scopolamine
1.5 mg topical patch behind ear
Onset of scopolamine
2-4 hours
DOA of scopolamine
72 hours
Metabolism of scopolamine
liver
elimination of scopolamine
4.5 hours
excretion of scopolamine
kidneys
Scopolamine should be avoided in
patients over 65 years of age
Adverse effects of scopolamine
dry mouth, increased thirst, dry skin, constipation, drowsiness, dizziness, blurred vision, dilated pupils, light sensitivity
Ephedrine Class
indirect-acting sympathomimetic agent
Dose of Ephedrine
10-25mg IV recommended for n/v associated with postual hypotension in PACU
MOA of Benzo
decreases dopamine’s emetic effect in the CTZ and decreases release of serontonin by binding to GABA receptor complex