Drugs used to treat or prevent vomiting or the feeling of sickness (nausea) are known as antiemetics.
Vomiting is a reflex action for getting rid of harmful substances, but it may also be a symptom of disease. Vomiting and nausea are often caused by a digestive tract infection, travel sickness, pregnancy, or vertigo (a balance disorder involving the inner ear). They can also occur as a side effect of some drugs, especially those used for cancer, radiation therapy, or general anaesthesia.
Commonly used antiemetics include metoclopramide, domperidone, cyclizine, haloperidol, ondansetron, granisetron, prochlorperazine, promethazine, and cinnarizine. The phenothiazine and butyrophenone drug groups are also used as antihistamines and to treat some types of mental illness .
Doctors usually diagnose the cause of vomiting before prescribing an antiemetic because vomiting may be due to an infection of the digestive tract or some other condition of the abdomen that might require treatment such as surgery.
Treating only the vomiting and nausea might delay diagnosis, correct treatment, and recovery. Antiemetics may be taken to prevent travel sickness (using one of the antihistamines), vomiting resulting from anticancer and other drug treatments (metoclopramide, haloperidol, domperidone, ondansetron, and prochlorperazine) to help the nausea in vertigo, and occasionally to relieve cases of severe vomiting during pregnancy. You should not take an antiemetic during pregnancy except on medical advice.
No antiemetic drug should be taken for longer than a couple of days without consulting your doctor.
Nausea and vomiting occur when the vomiting centre in the brain is stimulated by signals from three places in the body: the digestive tract, the part of the inner ear controlling balance, and the brain itself via thoughts and emotions and via its chemoreceptor trigger zone, which responds to harmful substances in the blood.
Antiemetic drugs may act at one or more of these places. Some help the stomach to empty its contents into the intestine. A combination may be used that works at different sites and has an additive effect.
As well as treating vomiting and nausea, many anti-emetic drugs may make you feel drowsy. However, for preventing travel sickness on long journeys, a sedating antihistamine may be an advantage.
Some antiemetics (in particular, the phenothiazines and antihistamines) can block the parasympathetic nervous system , causing dry mouth, blurred vision, or difficulty in passing urine.
The phenothiazines may also lower blood pressure, leading to dizziness or fainting.
| Gen name | Trade name |
| amisulpride | Barhemsys |
| doxylamine / pyridoxine | Bonjesta |
| doxylamine / pyridoxine | Diclegis |
| dronabinol | Marinol |
| dronabinol | Syndros |
| lorazepam | Ativan |
| lorazepam | Lorazepam Intensol |
| metoclopramide | Metozolv ODT |
| metoclopramide | Reglan |
| nabilone | Cesamet |
| netupitant / palonosetron | Akynzeo |
| phosphorated carbohydrate solution | Emetrol |
| phosphorated carbohydrate solution | Formula EM |