Which medications in the drug class Antiemetics are used in the treatment of Acetaminophen Toxicity?

Updated: Jan 17, 2020
  • Author: Susan E Farrell, MD; Chief Editor: Michael A Miller, MD  more...
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Emesis is frequently associated with APAP toxicity and is a common adverse effect of both AC and oral NAC administration. For these reasons, antiemetic therapy is often necessary to facilitate the successful administration of oral NAC. Persistent nausea or vomiting precludes oral NAC administration; in this situation, NAC should be administered intravenously.

Antiemetics that do not decrease gastric motility or significantly alter mental status are the drugs of choice; anticholinergic drugs such as prochlorperazine are not considered beneficial, in part because of their propensity to cause both of these adverse effects. Phenothiazines may also contribute to the potential toxicity associated with other anticholinergic drugs, if they are co-ingested with APAP-containing formulations.

Metoclopramide (Reglan, Metozolv)

Metoclopramide functions as an antiemetic by blocking dopamine receptors in the chemoreceptor trigger zone of the central nervous system. It also enhances gastrointestinal motility and accelerates gastric emptying time. This agent is of low cost and is generally considered an initial drug of choice for the treatment of nausea.

Ondansetron (Zofran, Zuplenz)

Ondansetron is a selective 5-hydroxytryptamine (5HT3) receptor antagonist. This drug blocks serotonin by acting on the vagus nerve peripherally and at the chemoreceptor trigger zone of the central nervous system (CNS). Ondansetron is considered more effective than metoclopramide, with fewer adverse effects, but it is more costly than metoclopramide.

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