Short answer
No standard capsule dose exists for chemotherapy. Dose depends on cannabinoid, product, patient, and chemo regimen. Two FDA-approved capsule medicines have fixed labels: dronabinol (Marinol, generic) and nabilone (Cesamet). Unapproved cannabis capsules sold in state programs do not have FDA-approved chemo doses. A clinician sets the dose.
Medical Cannabis Capsule Dosage for Pain: A Practical Guide
FDA-approved capsule doses
Dronabinol is a synthetic delta-9-THC capsule. For chemotherapy-induced nausea and vomiting, the FDA label states 5 mg/m2 by mouth 1 to 3 hours before chemo. Then 5 mg/m2 every 2 to 4 hours after chemo. Maximum 4 to 6 doses per day. Some labels list 2.5 mg, 5 mg, and 10 mg capsules.
medical thc capsule dosage calculator
Nabilone is a synthetic THC analog capsule. The FDA label states 1 mg or 2 mg by mouth twice daily for chemo nausea. Maximum 6 mg per day. Give first dose 1 to 3 hours before chemo. Capsules come in 1 mg.
medicinal marijuana capsule dosing guideline
Unapproved cannabis capsules
State-legal cannabis capsules contain plant THC, CBD, or both. Label claims may be wrong. Tests in some states find THC content differs from the label by 10% to 30% or more. No federal standard dose exists. Clinical studies use oral THC doses from 2.5 mg to 20 mg per dose. CBD doses in studies range from 100 mg to 600 mg per day. These are research doses, not product instructions.
Start low, go slow
For a patient new to THC capsules, a common approach is 1 mg to 2.5 mg THC. Wait 2 to 4 hours. Note effects. Increase by 1 mg to 2.5 mg per dose if needed. Do not drive after THC. THC can cause dizziness, dry mouth, fast heart rate, and confusion. CBD can cause sleepiness, diarrhea, and liver enzyme changes. CBD can raise blood levels of some chemo drugs.
Talk to the oncology team
Cannabis capsules can interact with chemo. Tell the oncologist about all cannabis use. Ask about dronabinol or nabilone first. These have FDA labels and known doses. For state-legal capsules, ask for a certificate of analysis. Check THC mg and CBD mg per capsule. Record dose, time, and symptoms. Do not stop chemo or change anti-nausea drugs without the oncologist.
Unknowns
No large trial gives a cannabis capsule dose for each chemo drug. Evidence for plant cannabis in chemo nausea comes from small trials. Response varies. Age, liver function, weight, and prior cannabis use change dose. Some patients need 2.5 mg THC. Others need 10 mg or more. No single number fits all.