Anti-Emetics Flashcards
Metoclopramide
Metoclopramide (Reglan)
Class: substitued benzamine, pro-kinetic agent
MOA: Dopamine antagonist centrally, acetylcholine and serotonin agonist in GI tract.
Blocks the action of dopamine at CRTZ, and also acts at acetylcholine and serotonin receptors to increase cAMP and increase peristalsis in GI smooth muscle.
uses:
tx PONV, anti-emetic
increase GI peristalsis, decrease gastric volume
tx of gastro-paresis
symptomatic tx of GERD
Pk:
onset: 1-3 minutes
DOA: 1-2 hours
E1/2T: 2-4 hours
PB: 40%
vd: 2-4 L/kg
Metabolized by liver, excreted 40% unchanged in urine.
Dose:
10-20 mg IV over 3-5 minutes, 15-30 minutes before induction.
peds: 0.15 mg/kg post T&A for PONV
SE:
Increase HR, decrease BP
Arrhthymia,
can lead to AV block if admin with zofran
rapid admin = abdominal cramping
akathesia/restless/agitation
EPS / oculogyric crisis
abnormal menstraution / lactation
C/I:
small bowel obstruction
parkinson’s dx
pheochromacytoma
may inhibit plasma cholinesteraes and prolong the actions of drugs like miva/succs
avoid concurrent admin with other dopamine antagonists like butyrphenones/phenothiazines
Ondansetron
Ondansetron (Zofran)
Serotonin receptor antagonist, anti-emetic.
blocks the action of serotonin centrally at the CRTZ and peripherally at vagal nerve terminals.
used for anti-emetic, PONV, not effective with motion sickness n/V or PONV r/t vestiublar motion sickness.
Pk:
Onset: 30 minutes
DOA: 4-8 hours
E1/2t: 3-4 hours
PB: 70%
metabloized by liver, has perfusion dependent metabolism.
Dose:
4-8 mg IV over 2 minutes
0.05 to 0.15 mg/kg for peds post op T&A
SE:
Headache with rapid admin
constipation / diarrhea
Prolongation of QT (worse in kids)
can lower seizure thresshold in kids
Sedation
AV block with co-administration of reglan
C/I:
Avoid with drugs that do increase QT: Butyrphenones, phenothiazines, amiodarine, quindine, erythromycin)
avoid with reglan.
Avoid with MAO-Is and SSRIs
Droperidol
Droperidol
2nd generation typical anti-pyschotic, butyrphenone.
MOA:
- Dopamine antagonist
- H1 antagonist
- Ach antagonist
- alpha adrenergic antagonist
Blocks the action of dopamine at CRTZ leadnig to anti-emetic effects.
Uses:
anti-emetic in surgery, also sedation, anti-pruritus and is an anti-psychotic.
Pk:
Onset: 30 minutes
DOA: 12 hours
e1/2T: 2 hours
PB: High
Vd: Large
Metabolism by liver, metabolism is perfusion dependent.
Dose:
0.6 to 2.5 mg IV for anti-emetic
up to 10 mg IV for sedation
SE:
Decrease HR
QT prolongation - black box warning
torsade’s du pont
protects aginst epi induced dysrthmias
vasodilation/ hypotension
drowsiness / sedation
EPS
neuromalignant syndrome
hallucinations / dystonia / dysphoria
C/I
drugs that can prolong QT - amiodarone, erythromycin, quinidine, metoclopramide
avoid with parkinson’s dx r/t dopamine antagonism
will potentiate the effects of anesthesia
Dexamethasone
Dexamethasone
Corticosteroid with only glucocorticoid action.
MOA:
Enters the cell and binds to glucocorticoid receptors in the cytoplasm forming a steroid-receptor complex that then enters the nucleus and alters DNA transcription. Leads to an increase in nutrient availability by increases blood glucose, amino acids, and triglycerides.
Inhibits the inflammatory response by inhibiting phospholipase A2 which decreases the formation of arachnidonic acid and subsequent inflammatory mediators such as cytokines, prostaglandins, and leukotrienes. Decreases capillary permability.
MOA for anti-emetic is unknown but is thought to be related to a decrease in prostaglandins.
Pk:
DOA: 24-36 hours, anti-emetic effect can last longer than 24 hours
E1/2T: 2-3 hours
Liver metabolism with 30% excreted unchanged in the urine.
Dose:
4-10 mg IV
SE:
Immunosuppression
sodium and water retention
hypokalemia
HTN
PERIANAL BURNING
Some HPA axis suppression, muscle and bone wasting, and fat redistribution with continued use.
Delayed woud healing
C/I:
caution in DM
Pts with untreated/active infection.
