Antiemetic Agents
Nausea and Vomiting
Most common and most uncomfortable complaints.
Vomiting is a complex reflex reaction to various stimuli.
Managing Nausea and Vomiting
Emetics
Cause vomiting
No longer recommended for at-home poison control
Antiemetics
Decrease or prevent nausea and vomiting
Centrally acting or locally acting
Varying degrees of effectiveness
Groups of Centrally Acting Antiemetics
Phenothiazines
Nonphenothiazines
Anticholinergics/Antihistamines
Serotonin (5-HT3) Receptor Blockers
Substance P/Neurokinin 1 Receptor Antagonists
Miscellaneous Group
Phenothiazines
Actions
Depresses various areas of the central nervous system (CNS)
Indications
Treatment of nausea and vomiting
Adverse Effects
Drowsiness
Nonphenothiazines
Actions
Acts to reduce the responsiveness of the nerve cells in the CTZ to circulating chemicals that induce vomiting
Indications
Prevention of nausea and vomiting
Adverse Effects
Drowsiness
Fatigue
Restlessness
Anticholinergics/Antihistamines
Actions
Anticholinergics that act as antihistamines and block the transmission of impulses to the CTZ
Indications
Prevention and treatment of nausea and vomiting
Adverse Effects
Drowsiness
Confusion
Dry mouth
Serotonin (5-HT3) Receptor Blockers
Actions
Block those receptors associated with nausea and vomiting in the CTZ and locally
Indications
Control of nausea and vomiting
Pharmacokinetics
Rapidly absorbed, metabolized in the liver, and excreted in urine and feces
Caution
Pregnancy and lactation
Substance P/Neurokinin 1 Receptor Antagonists
Actions
Act directly in the CNS to block receptors associated with nausea and vomiting
Indications
In combination with other agents to prevent nausea and vomiting
Pharmacokinetics
Given orally, metabolized in the liver, and excreted in urine and feces
Miscellaneous Antiemetics
Actions
Varies with agent
Indications
Treatment and prevention of nausea and vomiting
Pharmacokinetics
Varies according to agent
Prototype Phenothiazines
Prochlorperazine
Prototype Nonphenothiazines
Metoclopramide
Prototype Anticholinergics/
Antihistamines
Meclizine
Prototype Serotonin (5-HT3) Receptor Blockers
Ondansetron
Prototype Substance P/Neurokinin 1 Receptor Antagonists
Aprepitant