Medical cannabis for nausea: the short answer
Two cannabinoid drugs are FDA approved for nausea and vomiting caused by chemotherapy. Both contain THC or a THC analog. They are dronabinol (Marinol, Syndros) and nabilone (Cesamet). The FDA approved both in 1985.
Smoked or vaped cannabis flower is not FDA approved for any condition. Federal law lists it as Schedule I. Clinical trials on whole-plant cannabis for nausea are small and few. Most of the evidence covers the two prescription drugs.
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What the FDA approved drugs do
- Dronabinol. Synthetic THC. Capsules of 2.5 mg, 5 mg, and 10 mg, plus an oral solution. Schedule III.
- Nabilone. Synthetic THC analog. Capsules of 1 mg. Schedule II.
Both carry labels for nausea and vomiting from cancer chemotherapy when other antiemetics fail. Dronabinol also carries a label for AIDS-related anorexia.
Evidence base
The 2017 National Academies report reviewed more than 10,000 abstracts. It found substantial evidence that oral cannabinoids prevent and treat chemotherapy-induced nausea and vomiting. For smoked cannabis, the same report found limited evidence.
The National Cancer Institute PDQ summary lists dronabinol and nabilone as approved antiemetics. It notes that evidence for plant cannabis is weaker. The ASCO antiemetics guideline lists a cannabinoid as an add-on to standard drugs for cases that do not respond to other treatment. The guideline also flags side effects in older adults.
THC and CBD are not the same for nausea
The antiemetic effect tracks THC. CBD has less data and less consistent results. Epidiolex, the FDA approved CBD drug, is labeled for seizures, not nausea. Hemp-derived CBD sold online has no FDA approval for nausea and no standard dose.
THC causes side effects. These include dizziness, dry mouth, drowsiness, and falls in older adults. High doses can cause paranoia and a fast heart rate.
Forms and timing
Oral capsules take 30 to 90 minutes to act. Inhaled cannabis takes 1 to 10 minutes. Oral THC absorption is variable, with bioavailability near 10 to 20 percent after first-pass liver metabolism. Inhaled bioavailability runs about 10 to 25 percent.
A clinician sets the dose. Dronabinol doses in chemotherapy trials ranged from 2.5 mg to 10 mg.
Legal status in the US
Cannabis is Schedule I under federal law. More than 35 states and the District of Columbia run medical cannabis programs. Each state sets its own qualifying conditions. Nausea is not a qualifying condition in every state. Check your state program before you buy or possess.
What to ask a clinician
- Which antiemetic drugs have you already tried?
- Is a cannabinoid an option with my current prescriptions?
- What dose and form?
- What side effects should I watch for?