week 2 antiemetics gi motility- 4 of 4 Flashcards
T/F
pushing rapid IV raglan less than 3 minutes will cause abdominal cramping
true!
this is a side effect of rapid administration of IV reglan
this side effect of reglan hammon talked about in class- his patients in the er would just jump up and leave
akathisia (feeling of unease an restlessness in lower extremities) This may result in canceling surgery or may manifest in PACU
what are the cardiac side effects seen with reglan
hypotension, tachycardia, bradycardia, cardiac arrythmias
these side effects of reglan are rarely seen after a single dose
sedation dysphoria agitation dry mouth glossal or periorbital edema hirsutism urticarial maculopapular rash
patients with breast cancer should not be treated chronically with what medication
reglan
reglan rapidly crosses the placenta - do we see adverse fetal effects with single dose
no- not observed
for a patient on chronic therapy of reglan that develops peripheral edema what should we assess?
sodium retention and hypokalemia.
*This is due to that fact reglan inhibits dopamine-
dopamine normally inhibits aldosterone-
BUT reglan inhibits dopamine=elevated aldosterone=hypokalemia and sodium retention
reglan
May increase sedative actions of CNS depressants and the incidence of extrapyramidal reactions cause by certain drugs: Should avoid administering in combination with
Phenothiazine (prochlorperazine, promethazine, chlorpromazine)
Butyrophenone drugs (Doperidol and haldol)
Patients with preexisting extrapyramidal symptoms
Seizure disorders
these two medication classes should be avoided in patients taking reglan
MOAI or Tricyclic antidepressants
reglan decreases bioavailability of orally administered cimetidine by what percent
25-50%
what type of gastric issues do we avoid giving reglan to
suspected or known mechanical obstruction to gastric emptying
what GI surgery do we avoid administering reglan to?
why do we avoid reglan in these patients
pyloroplasty or intestinal anastomosis - it stimulates gastric motility and may delay healing
what are the effects of reglan on ester LA
metabolism of ester LA could be slowed by reglan induced decreases in plasma cholinesterase activity.
reglan inhibits plasma cholinesterase activity- which may prolong what two drugs
may cause prolonged responses to succinylcholine and mivacurium
who is at an especially increased risk for developing this prolonged responses of inhibiting effect of plasma cholinesterase activity when administering reglan
Parturients may be at increased risk for developing this response, considering the already decreased plasma cholinesterase activity associated with pregnancy.
BENZODIAZEPINES- ponv
May decrease PONV by decreasing synthesis and release of dopamine within the CRTZ.
If using a benzo for PONV therapy like versed when do you administered it
toward the end of the surgical procedure
if the patient is going to be ventilated in the ICU how can you administer the Versed for PONV
administer by continuous infusion
Droperidol prophylactic dose
0.625-1.25mg IV PONV
what was the primary reason droperidol was listed for a black box warning
the doses were MUCH higher than that necessary to treat PONV
what is the dose of haloperidol that does not cause sedation but has antiemetic properties
0.5-2mg IV
all meds that involve dopamine receptor blockade in the brain have a risk of “These” symptoms
extrapyramidal symptoms
due to the extrapyramidal symptoms caused from dopamine receptor blockade in the brain- caution should be used for what 3 disease types
parkinsons disease
RLS
Disease R/T dopaminergic activity
what type of drug is dexamethasone
corticosteroids
what is the mechanism of action for the use of dexamethasone as an antiemetic
unclear MOA
what has been proposed as the moa for dexamethasone for the use as an antiemetic
centrally inhibit prostaglandin synthesis and control endorphin release
one time use of dexamethasone will produce ... -minimal? -moderate? -maximum? side effects
minimal side effects
these two patient populations are at risk for perioperative hyperglycemia when they receive a single dose of dexamethasone
Diabetics (brittle/labile) and Obese
antagonism of 5-HT3 receptors=
antiemetic effect
which antiemetic receptor is an Excitatory ligand-gated nonselective cation.
5-HT3 Receptor Antagonists
5ht3 receptors are extensively distributed on enteric neurons in what two places
Gi and brain
what stimulates the vagal Afferents through 5-HT3 receptor and initiates the vomiting reflex
serotonin which is release from the enterochromaffin cells of the small intestines
T/F
5-HT3 receptor antagonist are highly specific and have minimal side effects
True
this drug class has been proven to be effective in prevention and treatment of PONV
5HT3 receptor antagonist
in addition to 5HT3 receptor antagonist being proven to be effective in prevention and treatment of PONV- what other types of N/V situation are they useful for as prophylaxis.
prophylaxis and treatment of chemotherapy and radiation therapy induced N/V
% protein bound - 5HT3 receptor antagonist
moderate
60-70%
metabolism of 5HT-3 receptor antagonist
different subtypes of the cytochrome P450
metabolites of 5HT3 receptor antagonist are excreted by what organ
primarly renal excretion
5HT3 receptor antagonist are readily absorbed - do they cross the BBB
yes they readily cross the BBB
IV administration=max brain concentration quickly
ondansetron 4mg
dexamethasone 4mg
droperidol 1.2mg
these drugs administered prophylactically before induction of general anesthesia are equally effective in decreasing PONV by what percent
26%
ondansetron - name the two most common side effect
headache
diarrhea
ondansetron therapeutic blood concentrations are achieved in how many minutes
30-60 minutes
how is ondansetron metabolized ?
what is the elimination half time
metabolized by liver
elimination half time is 3-4 hours
ondansetron is derived from _______ and structurally related to ________
carbazalone
serotonin
ondansetron possess specific 5-HT3 subtype receptor antagonist properties without altering what 4 receptor activity
dopamine, histamine, adrenergic or cholinergic receptor activity
what cardiac issues have been reported after IV zofran and reglan
cardiac arrhythmia and conduction disturbances (Atrioventricular block)
T/F
ondansetron can cause QT interval prolongation but not to the extent as droperidol
true
for every 100 patients receiving ondansetron for prevention of PONV 20 will not vomit who would have vomited without treatment- what will 3 of those 100 patients develop who would not have this adverse effect without the drug
3 - headache?
why do we have to know this?
ondansetron significant feature
free of side effects
zofran 4-8mg IV over 2-5 minutes immediately before the induction of anesthesia is highly effective in decreasing the incidence of ponv in susceptible pt population such as..
ambulatory gyno surgery, middle ear surgery
oral zofran for pre adolescent children dose
- 15mg/kg-PO
0. 05-0.15mg/kg- IV
what surgeries do we want to especially pre medicate children for
tonsillectomy and strabismus surgery ambulatory surgery
Name the drug that is almost as effective as ondansetron in preventing PONV 19-26%
propofol
dimenhydrinate (dramamine) dose for adult
decreases vomiting after
20mg IV
outpatient surgery
dimenhydrinate (dramamine) dose for children
decreases incidence of vomiting after?
0.5mg/kg IV
strabismus surgery
name the 4 medications Nonspecific antihistamines likely acting on H1 receptors include:
Diphenhydramine
Dimenhydrinate
Cyclizine
promethazine
what are the 3 subtypes of histamine
H1-H2-H3
Histamine acting through H1 receptors and inositol phospholipid hydrolysis evokes
smooth muscle contraction in GI tract
compared to ondansetron- what is the benefit of tropisetron
tropisetron has the benefit of a longer elimination half time- 7.3hr vs. 3.5hr
what disease process is tropisetron effective in treating symptoms of
carcinoid syndrome
what additional properties does tropisetron treat
gastrokinetic properties
compared to ondansetron: tell me about granisetron
it is more selective than ondansetron
what can be administered with granisetron to siginificantly improve the acute antiemetic efficacy
dexamethasone
name the 5ht3 antagonist that increases appetite
dolasetron
which 5ht3 antagonist medication is highly potent
dolasetron
explain the antiemetic effect of dolasetron
dolasetron is rapidly metabolized to hydrodolasetron- which is responsible for the antiemetic effect
