Cannabis and Cannabinoids

Patient Guide

Publication Date: March 12, 2024

Last Updated: March 13, 2024

Objective

This patient guideline summarizes key takeaways from the Cannabis and Cannabinoids in Adults with Cancer: American Society of Clinical Oncology (ASCO) Guideline.
The purpose of this guideline is to provide evidence-based recommendations on the medical use of cannabis and/ or cannabinoids for adults with cancer and their caregivers.

Overview

Cannabis is a plant (hemp) that is commonly known as marijuana or weed. It contains many chemical compounds known as cannabinoids.
The main cannabinoids present in cannabis are tetrahydrocannabinol (THC) and cannabidiol (CBD)
- THC can make you feel "high”. It also has medical uses.
- CBD does not make you “high”. It also has medical uses.
Other forms of cannabinoids include:
- Endogenous cannabinoids which are made in the human body.
- Synthetic cannabinoids (for example, dronabinol and nabilone), which are made in a lab.
Medical cannabis products are non-prescription plant-based products containing cannabinoids and used for health purposes.
Many adults with cancer use medical cannabis for the purpose of symptom management. They may get their information from non-medical sources. Therefore, this document provides scientific information about the clinical use of cannabis and cannabinoids and provides guidance for adults with cancer and their caregivers.

Clinical Communication and Education

You and your healthcare team should work together to share clear and unbiased information about cannabis and cannabinoids. This will help communication, decision-making, and planning for care.
Since many people with cancer use cannabis and/or cannabinoids, your healthcare team may regularly ask about your cannabis use or if you are thinking about using it. Based on your answers, your healthcare team will guide your care or direct you to helpful resources.
If you are using cannabis and/or cannabinoids in ways not recommended by your healthcare team, they will talk to you about your reasons, provide information, and help minimize any potential harm.

Cancer Treatment

It is recommended to avoid the use of cannabis and/or cannabinoids to replace your main cancer care. It is recommended to avoid the use of cannabis and/or cannabinoids to treat cancer itself, except in clinical trials (research studies).
Using cannabis and/or cannabinoids can cause the following problems (and there is not enough high-quality evidence to show clear benefits in treating cancer):
- Fatigue
- Confusion
- Feeling “high”
- Financial difficulties.

Cancer Treatment-related Toxicity, Symptoms, and Quality of Life (QOL)

Nausea and vomiting

The prescription medicines dronabinol and nabilone, or a quality-controlled oral cannabis products with equal amounts of THC and CBD can help adults with cancer who:
- receive chemotherapy which causes moderate or severe nausea and vomiting AND
- get medications beforehand to help prevent these symptoms AND
- still have nausea or vomiting.
There are also non-cannabis/ cannabinoid medications that can help with persistent nausea and vomiting.

Pain and other symptoms

The effects of cannabis and cannabinoids on cancer pain and other symptoms remain uncertain and warrant additional research.

Q&A

QUESTION 1: Should I discuss cannabis and/or cannabinoids with my healthcare team?

Yes.

At the present time, about 20% to over 40% of adults with cancer consume cannabis products. Therefore, discussing their use with your healthcare team is totally understandable and encouraged. They can guide you or your caregiver to appropriate resources.
If you mention that you are using cannabis and/or cannabinoids, your healthcare team may ask about the amount and types of cannabis products taken, including the THC:CBD ratio, the mode(s) of taking them (e.g., smoked or edible), and the perceived effectiveness and side effects.

QUESTION 2: Does the use of cannabis or cannabinoids carry any risks?

Yes.

Common side effects of THC-based products include dizziness, mild confusion, dry mouth, and fatigue.
More serious side effects include tachycardia (rapid heartbeat), orthostatic hypotension (low blood pressure when standing), severe confusion, and paranoia (excessive fear or suspicion.)
To minimize adverse effects from THC-based products, particularly in older adults and in those naïve (new) to cannabis and/or cannabinoids, such products should be started at a low dose and titrated (increased) slowly.

QUESTION 3: Does the onset of cannabis (how long for it to take effect) and duration of action (how long the effect lasts) differ according to how you take it?

Yes.

Smoking or vaping THC-predominant products: quick onset in seconds to minutes. Short duration lasting 2 to 3 hours.
Edible THC-predominant products: it takes from 30 minutes to 2 hours to start working, and effects may last from 5 to 8 hours.
Therefore, if you are an adult with cancer and new to oral cannabis and/or cannabinoid products, you should know that the onset of action may be more than one hour.
Be cautious to avoid stacking doses (taking multiple doses together or closely timed), which could lead to side effects as mentioned above.

QUESTION 4: Do cannabis or cannabinoids interact with standard cancer treatment?

Yes.

Interactions between drugs and cannabis may occur in the cancer setting.
Some examples are:
- Opioids
- Warfarin
- Buprenorphine
- Tacrolimus
Also, reversible liver enzyme elevations may occur at doses of 300 mg per day or higher with CBD-predominant products.

QUESTION 5: Should cannabis be used with the intent to treat cancer?

No.

The clinical evidence to support the use of cancer-directed therapy in humans is lacking.
You should not substitute cannabis and/or cannabinoids for standard cancer-directed treatment (the main treatments to fight cancer.)

QUESTION 6: Can cannabis and/or cannabinoids improve cancer side effects or symptoms?

Yes.

For example, they help with refractory chemotherapy-induced nausea and vomiting when standard approaches are ineffective.

QUESTION 7: Are there general safety measures?

Yes.

Store cannabis separate from other foods and drinks, in a locked location, and out of sight and reach of children and pets.
Avoid driving while under the influence of cannabis, which can more than double one's risk of a motor vehicle accident.
Substance use disorder history may predispose to problem cannabis use in the cancer setting.
Concurrent opioid use can increase risk for drug-drug interactions.
Cannabis use may worsen psychotic disorders.
Do not take edible cannabinoids with high-fat meals. Taking edible cannabinoids with high-fat meals significantly increases their absorption.

Source Citation

Braun IM, Bohlke K, Abrams DI, et al. Cannabis and Cannabinoids in Adults with Cancer: ASCO Guideline. J Clin Oncol. 2023 March 13. doi:10.1200/JCO.23.02596