Nausea is the feeling of sickness and wanting to vomit, though nausea does not always lead to vomiting. Nausea and vomiting are not always harmful but are common signs or side effects of many health problems, treatments and medications.

Medical cannabis often contains several compounds with antiemetic (anti-nausea and anti-vomiting) properties. Cannabis has been found to be particularly useful for managing nausea associated with chemotherapy.

Nausea causes

Nausea is more often a symptom of another underlying health problem than a condition in and of itself, although a condition called cyclic vomiting syndrome, or CVS, does exist. Nausea does not always lead to vomiting, but the causes and treatments are often the same.

Headaches and migraines can cause nausea, as can various drugs and medications. Many treatments or health problems can cause nausea and vomiting, including:

• Chemotherapy and cancer
• Fainting and dizziness
• Exposure to heat
• Stomach infections such as norovirus or food poisoning
• GI problems such as gastroesophageal reflux disease (GERD) or gastroparesis
• Low blood sugar
• Diabetes
• Motion sickness or any loss of balance resulting from disturbance of the inner ear
• Depression
• Anxiety
• Alcohol use
• Pregnancy and hyperemesis gravidarum (HG)
• Seeing, smelling and/or tasting something particularly vile

There are many other triggers.

Dopamine (D2), serotonin (5HT3), neurokinin (NK1), antihistamine, acetylcholine, and TRPV1 (vanilloid) receptors all play a role in causing the sensation of nausea. The group of receptors responsible for nausea and vomiting are often referred to as the “chemoreceptor trigger zone.”

Nausea symptoms & health effects

Nausea is an unpleasant feeling that can reduce a person’s quality of life (QoL). Signs, symptoms, and effects of nausea include:

• Feeling like you are about to vomit
• Vomiting
• Lack of appetite
• Stomach ache
• Feeling like you are overheating
• Profuse sweating, including cold sweats
• Shivering
• Retching (rhythmic labored spasmodic movements of the diaphragm & abdominal muscles)
• Uneasy feeling in your chest, upper abdomen, or back of your throat

Nausea diagnosis

If you are feeling persistently nauseous, then your physician will typically perform a physical exam, inquire about your symptoms and medical history, and look for signs of dehydration. Your doctor may also order tests and refer you to a specialist in order to determine any underlying conditions that could be causing nausea and vomiting.

Nausea prognosis

In most instances, nausea will go away on its own. Persistent nausea, however, may be the sign of a more serious underlying condition, and can severely impact a person’s quality of life. On its own, nausea or vomiting will not necessarily reduce life expectancy, but the condition it is associated with may do so.

If you are feeling nauseous and vomiting for more than three days or due to a head injury (no matter how light), then it is wise to see your doctor.

Nausea treatments

Treatment depends on the cause of the nausea. Generally, medications like antacids and antiemetics may be prescribed for nausea and vomiting.

First-line treatments

Typical first line treatments and medications include:

• Eating bland foods such as bread, potatoes, and rice to prevent indigestion and heartburn
• Bismuth subsalicylate (Pepto-Bismol, BisBacter), which is an antacid elixir medication used to treat temporary discomforts of the stomach and gastrointestinal tract
• Antihistamines, e.g. cinnarizine, cyclizine, promethazine hydrochloride, promethazine teoclate)

Other treatments

Should first-line treatments not work, other medications may be prescribed. These include:

• 5-HT3 receptor antagonists that block serotonin receptors, e.g., dolasetron (Anzemet) and granisetron (Kytril, Sancuso): These are usually prescribed for post-operative and cytotoxic drug nausea and vomiting.
• Dopamine antagonists, which block dopamine receptors on the brain stem, e.g., domperidone (Motilium) and olanzapine (Zyprexa). These are usually prescribed for nausea and vomiting associated with chemotherapy, radiation sickness, opioids, cytotoxic drugs, and general anesthetics.
• NK1 receptor antagonists such as aprepitant (Emend) and rolapitant (Varubi).
• The antidepressant mirtazapine (Remeron), which is also an antihistamine.
• Synthetic cannabinoids like dronabinol, levonantradol, and nabilone, which are structurally similar to delta-9-THC (but more potent), may be prescribed for managing nausea and vomiting associated with chemotherapy.

Adjunctive therapy & alternative treatments

Non-medical interventions for less chronic or severe nausea and vomiting include fresh air, sipping on cold drinks, and healthy, well-planned meals at fixed times of the day. Those who have food intolerances may need a change in diet.

Ginger, cloves, peppermint, chamomile, meadowsweet, and Devil’s Claw are common herbal remedies.

Cannabis for nausea

Antiemetics are generally well-tolerated, but they can have side effects such as constipation or diarrhea, headache, fatigue, malaise, dizziness, light-headedness, blurred vision, dry mouth, or photosensitivity. Some people may find some classes of antiemetics to be intolerable or ineffective.

Medical cannabis could be helpful in reducing or replacing the need for antiemetic medications, or as an effective alternative in the case of treatment resistance. Many find plant-derived cannabinoids (phytocannabinoids), such as a mixture of tetrahydrocannabinol (THC) and cannabidiol (CBD), more tolerable compared to synthetic ones like dronabinol and nabilone.

Cannabis also contains several compounds that have antiemetic properties, including THC, CBD,, and cannabichromene (CBC). THC, CBD, and CBC exert their antiemetic properties via interaction with cannabinoid receptor 1 (CB1) and serotonin receptor 5-HT3. Serotonin receptors are a common target for many antiemetic drugs.

Moreover, as phytocannabinoids and terpenes affect multiple receptors and have a wide range of effects, cannabis can be utilized as an analgesic, anti-inflammatory, antidepressant, and anticonvulsant as well as an antiemetic. This can help reduce the intake of other medications that may contribute or cause nausea and vomiting. The multi-therapeutic effects of cannabis are of particular use for cancer patients, who often have to manage pain, anxiety, insomnia, and appetite loss alongside nausea and vomiting.

It should be noted that overconsumption of THC and cannabigerol (CBG) may induce nausea and vomiting in some. According to animal studies, moderate-to-high doses of CBG may oppose the antiemetic effects of THC and CBD.

Additional information for patients

For those experiencing severe nausea and vomiting due to pregnancy, there are the charities like HER Foundation and March of Dimes.

Nausea FAQs

How long is too long for nausea and vomiting?

If you have been feeling nauseous and vomiting for longer than three days, then you should speak to a doctor as soon as possible. Those experiencing on-and-off bouts of nausea and vomiting for a month or longer should also see a doctor.

Why am I feeling nauseous without vomiting?

Nausea does not always lead to vomiting. One of the main reasons for nausea without vomiting is a digestive issue, although headaches & migraines and indigestion can also have the same effect.

When should I be concerned about nausea?

You should be concerned about nausea if you:

• Have vomited and have seen blood in your vomit
• Recently suffered a head injury
• Experience persistent nausea for longer than 3 days
• Experience significant weight loss
• Experience severe chest or abdominal pain or cramping
• Experience blurred vision with or without head pain

Can medical cannabis be used for severe nausea/vomiting during pregnancy (hyperemesis gravidarum)?

Although there are studies reporting positive outcomes with cannabis use for those with hyperemesis gravidarum, it should be noted that we know little about the effects of cannabis use on fetal health and development. Although cannabis use during pregnancy has not been strongly linked to birth defects, it has been linked to low birth weight, reduced alertness, slower growth, and negative impacts on the developing brain during childhood and adolescence.

Resources

• Physiology, Chemoreceptor Trigger Zone: https://www.ncbi.nlm.nih.gov/books/NBK537133/
• Levonantradol: https://www.cancer.gov/publications/dictionaries/cancer-drug/def/levonantradol
• Comparison of the Effectiveness and Tolerability of Nabiximols (THC:CBD) Oromucosal Spray versus Oral Dronabinol (THC) as Add-on Treatment for Severe Neuropathic Pain in Real-World Clinical Practice: Retrospective Analysis of the German Pain e-Registry: https://pmc.ncbi.nlm.nih.gov/articles/PMC8819705/
• Cannabinoid Antiemetic Therapy: https://www.ncbi.nlm.nih.gov/books/NBK535430/
• Interaction between non-psychotropic cannabinoids in marihuana: effect of cannabigerol (CBG) on the anti-nausea or anti-emetic effects of cannabidiol (CBD) in rats and shrews: https://pubmed.ncbi.nlm.nih.gov/21243485/
• The use of cannabis for Hyperemesis Gravidarum (HG): https://jcannabisresearch.biomedcentral.com/articles/10.1186/s42238-020-0017-6
• Prenatal, Perinatal, and Neonatal Exposure to Cannabis: https://www.ncbi.nlm.nih.gov/books/NBK425751/
• Prenatal Cannabis Use and Maternal Pregnancy Outcomes: https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2821358

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