Answer first
No single dose of medical cannabis treats nausea in every person. Dose depends on product, route, THC and CBD content, body weight, and prior cannabis use. Clinical guidance for oral THC starts at 2.5 mg to 5 mg. Inhaled doses start smaller, often 1 puff of flower with about 10% THC. Wait at least 15 minutes before a second inhaled dose. Wait at least 2 hours before a second oral dose.
cannabis for chemotherapy nausea symptoms
The FDA has approved two synthetic cannabinoid drugs for chemotherapy-induced nausea and vomiting: dronabinol and nabilone. The FDA has not approved plant cannabis for nausea.
cannabis for chemotherapy nausea symptoms
What the evidence covers
Most evidence on cannabinoids for nausea comes from chemotherapy-induced nausea and vomiting. Trials use dronabinol, nabilone, or oral THC. Data on smoked cannabis and CBD for nausea are thinner. Reviews report few high-quality trials for plant cannabis.
Medical Cannabis for Appetite Nausea Syndrome: A Practical Guide
- Dronabinol: oral capsule. Trials use 5 mg/m2 before chemotherapy, then 5 mg/m2 every 2 to 4 hours after chemotherapy, up to 6 doses per day. This is a prescription dose, not a dispensary dose.
- Nabilone: oral capsule. Trials use 1 mg to 2 mg twice daily. This is a prescription dose.
- Plant cannabis: no standard dose. Start low. Go slow.
Dosing by route
Route changes onset and duration. Inhaled cannabis reaches peak effect in 15 to 30 minutes. Oral cannabis reaches peak effect in 2 to 4 hours. Edibles can last 6 to 8 hours.
- Inhaled: start with 1 puff. Wait 15 minutes. Increase by 1 puff if nausea persists.
- Oral: start with 2.5 mg THC. Wait 2 hours. Increase by 2.5 mg if nausea persists.
- Sublingual tincture: start with 1 mg to 2.5 mg THC. Hold under the tongue. Wait 30 to 60 minutes.
- Topical: not a nausea treatment. Topicals do not produce systemic THC levels that treat nausea.
THC and CBD
THC has the most evidence for nausea relief. CBD has less evidence for nausea. CBD may reduce THC anxiety, but it can also change THC effects. A 1:1 THC:CBD product may suit some patients. A high-THC product may cause anxiety, dizziness, fast heartbeat, and nausea in new users. Start with a low-THC product.
Product labels
US legal cannabis labels list THC and CBD per serving and per package. Check the serving size. One mint may contain 2.5 mg THC. One chocolate square may contain 10 mg THC. One tincture drop may contain 0.5 mg THC. Do not assume one piece equals one dose.
Safety
Do not drive or use machines after cannabis. Avoid cannabis in pregnancy and breastfeeding. Avoid cannabis with a history of psychosis or heart disease. CBD can raise blood levels of clobazam, warfarin, and other drugs through CYP450 enzymes. Talk to a pharmacist about interactions.
When to seek care
Seek care if vomiting prevents fluids, nausea lasts more than 24 hours, or you have severe abdominal pain. Daily high-dose THC use can cause cannabinoid hyperemesis syndrome. Signs include repeated vomiting, abdominal pain, and relief from hot showers.