Antiemetic drugs are types of chemicals that help ease symptoms of nausea or vomiting. Antiemetic drugs may also be used to treat nausea and vomiting caused by other medications, frequent motion sickness, infections, or stomach flu.
Antiemetic drugs help to block specific neurotransmitters in the body. These neurotransmitters trigger impulses such as nausea and vomiting, so blocking the impulses will help shut them down.
Feeling nauseated might seem like a simple reaction in the body, but it is a complex process. Because of this, there is a range of antiemetic drugs, each of which is designed to work in different situations.
There are many different causes of nausea, and certain classes of antiemetic drugs are designed to treat each cause. Below are the most common antiemetic drugs, grouped by the kind of nausea they can treat:
Antiemetic drugs for motion sickness
Some antihistamine medications may help prevent nausea and vomiting caused by motion sickness. A few of these medications are available as over-the-counter drugs.
These medications desensitize the inner ear to the motion of the head. The inner ear plays a significant role in a person’s balance, which can be affected by sitting in a moving car or being on a boat.
Antiemetics for motion sickness include:
- dimenhydrinate (Dramamine, Gravol)
- diphenhydramine (Benadryl)
- meclizine (Bonine)
- promethazine (Phenergan)
Each of these medications may cause side effects, which a person should discuss with a doctor or pharmacist if they have not used a drug before.
Antiemetic drugs for surgery
People who require anesthesia to undergo surgery frequently complain of nausea and vomiting following the surgery. A few different types of drugs can help with this, such as serotonin receptor blockers, dopamine receptor blockers, and some corticosteroids.
Antiemetic drugs doctors may prescribe after surgery include:
- dexamethasone (Decadron)
- droperidol (Inapsine)
- metoclopramide (Reglan)
- ondansetron (Zofran)
Antiemetic drugs for cancer patients and chemotherapy
Chemotherapy treatment will often cause nausea and vomiting. Doctors may prescribe different antiemetic drugs both before and after chemotherapy treatment to help prevent symptoms and allow the person to experience a higher quality of life.
Different types of drugs may help with this, including serotonin and dopamine receptor blockers, NK1 receptor blockers, and corticosteroids.
Some antiemetic drugs for chemotherapy include:
- aprepitant (Emend)
- dexamethasone (DexPak)
- dolasetron (Anzemet)
- granisetron (Kytril)
- ondansetron (Zofran)
- palonosetron (Aloxi)
- prochlorperazine (Compazine)
- rolapitant (Varubi)
Cannabinoids from medical marijuana or prescription drugs such as dronabinol (Marinol) also show promise in reducing symptoms of nausea and vomiting in people who respond negatively to other drugs. These drugs still have a risk of side effects, however.
Antiemetics for stomach flu
While vomiting can help get rid of stomach irritants, excessive vomiting can damage the digestive tract. Nausea may also prevent a person with the stomach flu from eating, even though their body needs nutrients.
Over-the-counter medications such as sodium citrate/dextrose/fructose (Nauzene), phosphoric acid (Emitrol), or bismuth subsalicylate (Pepto-Bismol) can help soothe an upset stomach as the body fights off the infection.
Antiemetics during pregnancy
Pregnant women with morning sickness may use antiemetic drugs to reduce their symptoms. They are usually only prescribed in severe situations, such as if a woman has hyperemesis gravidarum or where nausea and vomiting interfere with everyday life.
A few different medications may work as antiemetics during pregnancy. Doctors will want to discuss any possible side effects of each drug on the mother and baby.
Some antiemetics for morning sickness include:
- dimenhydrinate (Dramamine)
- prochlorperazine (Compazine)
- promethazine (Pentazine)
- vitamin B-6
Doctors may also prescribe metoclopramide (Reglan) for women who do not respond well to other treatments. Using cannabis or marijuana during pregnancy is not safe, as it may affect the developing fetus.
Each antiemetic drug may have a specific list of side effects, so a person should be sure to read the information that comes with their particular medication, or ask the pharmacist to go over the side effects with them.
Understanding which side effects a person is most sensitive to may help doctors choose the best prescription to treat their symptoms.
Common side effects of each drug type include:
- Antihistamines: sleepiness, dry mouth, and dry nasal passages
- Bismuth-subsalicylate: dark, blackish stools and changes in tongue color
- Cannabinoids: altered state of perception and dizziness
- Corticosteroids: additional symptoms of indigestion, increased appetite or thirst, and acne
- Dopamine receptor blockers: fatigue, constipation, ringing in the ears, dry mouth, restlessness, and muscle spasms
- NK1 receptor blockers: dry mouth, reduced urine volume, and heartburn
- Serotonin receptor blockers: fatigue, dry mouth, and constipation
Each specific medication may have additional side effects as well.
While antiemetic drugs can help people to live without the bothersome symptoms of nausea and vomiting, some complications can occur.
Symptoms that should be addressed by a doctor include:
- muscle weakness, spasms, or convulsions
- changes in heartbeat, such as palpitations or rapid heartbeat
- hearing loss
- worsening of nausea or vomiting, even while taking medications
- slurred speech
- psychological problems, such as hallucinations or confusion
- drowsiness that interferes with daily life
It is best to discuss medications with a doctor before starting any new prescription, especially if a person is taking other drugs.
For instance, people who take sleeping pills or muscle relaxants will need to talk to their doctor before taking over-the-counter antihistamines for nausea and vomiting.
Other medications have side effects similar to those caused by antiemetics. Taking more than one of these drugs at the same time may make the side effects worse.
Medications with similar side effects include:
Some natural antiemetic options exist for people who want to avoid chemical drugs.
Ginger root is the best known natural antiemetic that is used to combat symptoms such as nausea and upset stomach. Ginger root is now available in candies, drinks, and teas.
As research has noted, ginger significantly reduces symptoms of nausea and vomiting in many people. More in-depth studies are needed to support these claims, but the initial evidence is positive.
The essential oils from some herbs may also help with nausea and vomiting. Peppermint, spearmint, lemon, and ginger essential oil may help with symptoms in many people and can be used by adding them to a diffuser or wafting a bottle under the nose.
Whether a person chooses a natural antiemetic or a chemical drug, it is always best to discuss any new treatments with a doctor. With a doctor’s help, many people can find the right medicine to relieve symptoms of nausea and vomiting and avoid any other complications.