Antiemetic

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An antiemetic is a drug that is effective against vomiting and nausea. Antiemetics are typically used to treat motion sickness and the side effects of opioid analgesics, general anaesthetics, and chemotherapy directed against cancer.

Anti-emetics are also used for morning sickness, but there is little information about the effect on the fetus, and doctors prefer not to use them unless it is strictly necessary.^[1]

Types of antiemetics [edit]

Antiemetics include:

• 5-HT₃ receptor antagonists – these block serotonin receptors in the central nervous system and gastrointestinal tract. As such, they can be used to treat post-operative and cytotoxic drug nausea & vomiting. However, they can also cause constipation or diarrhea, dry mouth, and fatigue. ^[2]
  • Dolasetron (Anzemet) - can be administered in tablet form or in an injection.
  • Granisetron (Kytril, Sancuso) - can be administered in tablet (Kytril), oral solution (Kytril), injection D(Kytril), or in a single transdermal patch to the upper arm (SANCUSO).
  • Ondansetron (Zofran) - administered in an oral tablet form, oral dissolving tablet form, or in an injection.
  • Tropisetron (Navoban) - can be administered in oral capsules or in injection form.
  • Palonosetron (Aloxi) - can be administered in an injection or in oral capsules.
  • Mirtazapine (Remeron), an antidepressant that also has antiemetic effects. ^[3] Is also a potent histamine H1 antagonist, K_i=5.1nM. ^[4]
• Dopamine antagonists act in the brain and are used to treat nausea and vomiting associated with neoplastic disease, radiation sickness, opioids, cytotoxic drugs and general anaesthetics. Side effects include muscle spasms and restlessness. ^[2]
  • Domperidone
  • Olanzapine
  • Droperidol, haloperidol, chlorpromazine, promethazine, prochlorperazine. Some of these drugs are limited in their usefulness by their extra-pyramidal and sedative side-effects.
  • Alizapride
  • Prochlorperazine (Compazine, Stemzine, Buccastem, Stemetil, Phenotil)
  • Metoclopramide (Reglan) also acts on the GI tract as a pro-kinetic, and is thus useful in gastrointestinal disease; however, it is poor in cytotoxic or post-op vomiting. also a 5-HT₃ receptor antagonists
• NK1 receptor antagonist
  • Aprepitant (Emend) Commercially available NK1 Receptor antagonist
  • Casopitant Investigational NK1 receptor antagonist
• Antihistamines (H₁ histamine receptor antagonists), effective in many conditions, including motion sickness, morning sickness in pregnancy, and to combat opioid nausea.
  • Cyclizine
  • Diphenhydramine (Benadryl)
  • Dimenhydrinate (Gravol, Dramamine)
  • Doxylamine
  • Meclozine (Bonine, Antivert)
  • Promethazine (Pentazine, Phenergan, Promacot) Promethazine can be administered via a rectal suppository for adults and children over 2 years of age.
  • Hydroxyzine
• Cannabinoids are used in patients with cachexia, cytotoxic nausea, and vomiting, or who are unresponsive to other agents. These may cause changes in perception, dizziness, and loss of coordination. ^[2]
  • Cannabis - Medical marijuana, in the U.S., it is a Schedule I drug.^{[citation needed]}
  • Dronabinol (Marinol) - a Schedule III drug in the U.S.^{[citation needed]}
  • Some synthetic cannabinoids such as Nabilone (Cesamet) or the JWH series.
  • Sativex is an oral spray containing THC and CBD. It is currently legal in Canada and a few countries in Europe but not legal in the U.S.^{[citation needed]}
• Benzodiazepines
  • Midazolam given at the onset of anesthesia has been shown in recent trials to be as effective as ondansetron.^{[citation needed]}
  • Lorazepam is said to be very good as an adjunct treatment for nausea along with first line medications such as Compazine or Zofran.^{[citation needed]}
• Anticholinergics
  • Hyoscine (also known as scopolamine)
• Steroids
  • Dexamethasone (Decadron) given in low dose at the onset of a general anaesthetic is an effective anti-emetic. The specific mechanism of action is not fully understood.^{[citation needed]}
• Other
  • Trimethobenzamide; thought to work on the CTZ
  • Ginger - contains 5HT3 antagonists gingerols and shogaols. ^[5]
  • Emetrol also claimed to be an effective antiemetic.
  • Propofol given intravenously. It has been used in an acute care setting in hospital as a rescue therapy for emesis.^{[citation needed]}
  • Peppermint claimed to help nausea or stomach pain when added into a tea or peppermint candies.
  • Muscimol purported as such. ^[6]
  • Ajwain purported to be antiemetic. It is a popular spice in India, Ethiopia and Eritrea.^{[citation needed]}

References [edit]

See also [edit]

• Emetic
• Hyperemesis gravidarum
• Chemotherapy