II. Mechanism

  1. Nausea and Vomiting is mediated via the physiologic Vomiting center in the Medulla
    1. D2 Dopamine Stimulation of ChemoreceptorTrigger Zone (CTZ) in Medulla
    2. Many Antiemetics are dopamine Antagonists (e.g. Phenothiazines, Antipsychotic Medications)
    3. Serotonin Antagonists (5-HT3) are among the most commonly used Antiemetics
    4. Some Antihistamines (e.g. Diphenhydramine) and Anticholinergic Medications have Antiemetic properties (unclear mechanism)
  2. Stimulation of Vomiting center via three pathways
    1. Vestibular fibers (e.g. Vertigo)
    2. Afferent visceral fibers (e.g. gastrointestinal)
    3. Fourth Ventricle (ChemoreceptorTrigger Zone)

III. Preparations: 5-HT3 Receptor Antagonist

  1. Indications
    1. Preferred first-line Antiemetic in U.S. in most cases
    2. Severe Nausea and Vomiting
    3. Postoperative Nausea and Vomiting
    4. Chemotherapy-Induced Vomiting (See Nausea in Cancer)
  2. Agents
    1. Ondansetron (Zofran)
    2. Granisetron (Kytril)
    3. Dolasetron (Anzemet)
    4. Palonosetron (Aloxi)
  3. Adverse effects
    1. Asthenia
    2. Dizziness
    3. Constipation
    4. QT Prolongation (see Ondansetron)
    5. Serotonin Syndrome
    6. Use in pregnancy may be associated with increased risk of Congenital Heart Defect and Cleft Palate
      1. (2014) Presc Lett 21(1): 5

IV. Preparations: Dopamine Antagonists - Phenothiazines

V. Preparations: Dopamine Antagonists - Substituted Benzamides

VI. Preparations: Dopamine Antagonists - Butyrophenones

  1. Agents
    1. Droperidol (Inapsine)
    2. Haloperidol (Haldol)
  2. Indications
    1. Chemotherapy-Induced (See Nausea in Cancer)
    2. Postoperative Nausea (See Nausea After Surgery)
  3. Adverse Effects
    1. Sedation
    2. Agitation or restlessness

VII. Preparations: Sedating Antihistamines (H1 Blockers)

VIII. Preparations: Neurokinin-1 Receptor Antagonist (NK1 Receptor Antagonist, Substance P Inhibitor)

  1. Agents
    1. Aprepitant (Emend, Cinvanti, Fosaprepitant)
    2. Rolapitant (Varubi)
    3. Netupitant (Akynzeo)
  2. Indications
    1. Prevention of Nausea, Vomiting with highly emetogenic Chemotherapy
      1. Typically used in combination with 5-HT3 Antagonists and Dexamethasone 20 mg daily
  3. Adverse Effects
    1. Asthenia or Fatigue
    2. Hiccups

IX. Preparations: Adjunctive and Atypical Antiemetics

  1. Dexamethasone
    1. Chemotherapy-Induced (See Nausea in Cancer)
  2. Cannabinoids (Dronabinol)
    1. Chemotherapy-Induced (See Nausea in Cancer)
  3. Benzodiazepines (Lorazepam, Diazepam, Clonazepam)
    1. Chemotherapy-Induced (See Nausea in Cancer)
    2. Not generally recommended
  4. Isopropyl Alcohol 70% Wipes
    1. Fold Alcohol wipe in half and hold within a half centimeter of the nares
    2. Take 3 deep inhalations every 5 to 15 minutes as needed (may be repeated up to 3 times)
    3. May reduce the need of medications in Postoperative Nausea and Vomiting
    4. Pellegrini (2009) AANA J 77(4): 293-9 [PubMed]
    5. Cotton (2007) AANA J 75(1): 21-6 [PubMed]

X. Preparations: Brief list of Antiemetics for Adults

  1. Ondansetron (Zofran)
    1. Dose: 4 mg (0.15mg/kg) IV (or PO) over 15 min every 4 hours as needed
  2. Metoclopramide (Reglan)
    1. Dose: 5 to 10 mg PO/IM/IV every 6 hours as needed or 1 hour before meals and at bedtime
  3. Prochlorperazine (Compazine)
    1. PO/IM/IV: 5-10 mg every 6-8 hours as needed
    2. Rectal: 25 mg PR g12h
  4. Promethazine (Phenergan)
    1. Dose: 12.5 mg IV or 25 mg PO/IM/PR every 4 to 6 hours

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Related Studies

Ontology: Antiemetics (C0003297)

Definition (MSH) Drugs used to prevent NAUSEA or VOMITING.
Definition (NCI_NCI-GLOSS) A drug that prevents or reduces nausea and vomiting.
Definition (NCI) Drugs used to prevent nausea or vomiting. Antiemetics act by a wide range of mechanisms. Some act on the medullary control centers (the vomiting center and the chemoreceptive trigger zone) while others affect the peripheral receptors. (MeSH)
Definition (CSP) drugs used to prevent nausea or vomiting; act by a wide range of mechanisms; some act on the medullary control centers while others effect the peripheral receptors.
Concepts Pharmacologic Substance (T121)
MSH D000932
SnomedCT 372764000, 52017007
English Antiemetic Drugs, Drugs, Antiemetic, Agents, Antiemetic, Antiemetic Agents, ANTIEMETICS, [GA605] ANTIEMETICS, Anti-emetic, Anti-emetic Agent, Anti-emetic Agent [TC], Antiemetic Agent, anti-emetic agents, antiemetic drugs, antiemetic agents, antiemetics, antiemetic drug, antiemetic, antinauseant drugs, Antiemetic, Antiemetic (product), Antiemetic (substance), Antiemetic, NOS, Anti emetics, Anti-emetics, Antinauseant Drugs, Antiemetics
French Agents antiémétiques, Anti-émétiques, Médicaments antiémétiques, Médicaments antivomitifs, Antiémétisants, Agents antivomitifs, Anti-vomitifs, Antiémétiques, Antivomitifs
Swedish Antiemetika
Czech antiemetika
Finnish Antiemeetit
Italian Sostanze antiemetiche, Farmaci antiemetici, Antiemetici
Russian PROTIVORVOTNYE SREDSTVA, ПРОТИВОРВОТНЫЕ СРЕДСТВА
Japanese 制吐剤, 制吐薬, 鎮吐剤, 鎮吐薬
Polish Leki przeciwwymiotne
Spanish Efecto Antiemético, Antiemético, antiemético (producto), antiemético (sustancia), antiemético, Antieméticos
Portuguese Efeito Antiemético, Antiemético, Antieméticos
German Antiemetika

Ontology: Phenothiazines (C0031436)

Definition (MSH) Compounds containing dibenzo-1,4-thiazine. Some of them are neuroactive.
Concepts Organic Chemical (T109) , Pharmacologic Substance (T121)
MSH D010640
LNC LP16248-4, MTHU042526
English Phenothiazines, phenothiazines (medication), phenothiazines, Phenothiazines [Chemical/Ingredient]
Swedish Fentiaziner
Czech fenothiaziny, piperacetazin
Finnish Fentiatsiinit
Russian PROPERITSIAZIN, PROPIOMAZIN, PIPOTIAZIN, TIOPROPERAZIN, BUTAPERAZIN, PERITSIAZIN, PIPERATSETAZIN, FENOTIAZINY, PROFENAMINA GIDROKHLORID, MAZHEPTIL, ETOPROPAZIN, NEULEPTIL, RANDOLEKTIL, БУТАПЕРАЗИН, МАЖЕПТИЛ, НЕУЛЕПТИЛ, ПЕРИЦИАЗИН, ПИПЕРАЦЕТАЗИН, ПИПОТИАЗИН, ПРОПЕРИЦИАЗИН, ПРОПИОМАЗИН, ПРОФЕНАМИНА ГИДРОХЛОРИД, РАНДОЛЕКТИЛ, ТИОПРОПЕРАЗИН, ФЕНОТИАЗИНЫ, ЭТОПРОПАЗИН
Croatian FENOTIAZINI
Polish Fenotiazyny pochodne
Japanese アパミンカリュウ, フェノチアジン, フェノチアジン誘導体, アパミンジョウ10MG, アパミンジョウ25MG, アパミンジョウ5MG, ブタペラジン, プロピオマジン
French Phénothiazines
German Phenothiazine
Italian Fenotiazine
Portuguese Fenotiazinas
Spanish Fenotiazinas