Antiemetics Flashcards
Ondansetron: Class
5-HT3 receptor antagonist
Ondansetron: use
PONV
Chemotherapy related N/V
Carcinoid Syndrome
Ondansetron: Mechanism of Action
Inhibits serotonin both peripherally on vagus nerve terminals and centrally in the medulla’s Chemoreceptor trigger zone (CRTZ)
Ondansetron: Dose
4 - 8 mg
Ondansetron: Pharmacokinetics
Absorption: IV, PO
Onset: 10 minutes
Duration of Action: 4 hours
Metabolism: Hepatic
Elimination: Renal
Ondansetron: Contraindications
Prolonged QT interval
Hypersensitivity
Ondansetron: Considerations
Can cause Headache
prolongs QT interval
Dexamethasone: Class
Synthetic glucocorticoid steriod
Dexamethasone: Use
Decrease PONV risk
Reduce edema
Reduce postoperative pain
Dexamethason: Mechanism of Action
↓ inflammation by inhibiting prostaglandin synthesis (from Vargo)
Dexamethasone’s mechanism of antiemetic activity is not entirely known, however:
↓ prostaglandin synthesis = ↓ N+V
decreases inflammation by suppression of migration of polymorphonuclear leukocytes and reversal of increased capillary permeability
inhibits phospholipase that is necessary for the conversion of phospholipids to arachidonic acid, which leads to the inflammatory chain reaction along both the cyclooxygenase and lipoxygenase pathways =↓ painq
Dexamethasone: Dose
4 - 12 mg
Dexamethasone: Pharmacokinetics
Absorption: IV, PO
Onset: 30 minutes
Duration of action: 36 hours
Metabolism: Hepatic
Elimination: Renal
Dexamethasone: Contraindications
Systemic fungal infections
Live virus vaccines
Allergy/hypersensitivity
Dexamethasone: Considerations
Delayed wound healing
HPA axis surpression
Hyperglycemia
Perianal itching (why it’s given after induction)