December 26, 2018
3 min read

Can medical marijuana replace opioids to relieve cancer pain?

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

We were unable to process your request. Please try again later. If you continue to have this issue please contact

Click here to read the Cover Story, “Knowledge of benefits, harms of medical marijuana for cancer ‘far from complete’”


In some scenarios.

I can conceive of some clinical scenarios in which marijuana is used as a replacement for high-dose opioids. For instance, it might make sense for medical marijuana to be used in patients already on opioids and at increased risk for opioid-related harm.

Anna Lembke, PhD
Anna Lembke

This does not mean that I believe marijuana is the solution to the opioid epidemic. Far from it. Nor do I recommend marijuana for the treatment of chronic pain. Nonetheless, for patients with cancer pain already on high-dose opioids who are at imminent risk for adverse consequences related to those opioids — such as patients with increased pain due to opioids, also known as opioid-induced hyperalgesia; patients at increased risk for accidental overdose, including patients being co-prescribed benzodiazepines; patients with obstructive sleep apnea; patients with prior history of opioid overdose; or patients with past or current opioid addiction — marijuana represents a possible harm-reduction strategy.

Replacing opioids with marijuana in this limited clinical setting might reduce the risk for death as it is difficult, if not impossible, to overdose on marijuana. I have had patients under my care on dangerously high doses of opioids for pain who have successfully transitioned off of opioids by switching to marijuana, and who are doing better as a result. I have also had patients who attempted the same, and ended up on both opioids and marijuana with no clinical benefit. Some patients are clearly worse off after adding marijuana in an attempt to taper off of opioids, either because they become psychotic on marijuana, or because they became addicted to marijuana.

I might also add that medical marijuana in place of opioids is a potential harm-reduction strategy for prescribers, who are increasingly medicolegally liable for continuing patients on high-dose opioids.

Anna Lembke, PhD, is associate professor in the department of psychiatry and behavioral sciences at Stanford University School of Medicine and program director of Stanford University Addiction Medicine Fellowship. She can be reached at Stanford University School of Medicine, 401 Quarry Road, Room 2208, Stanford, CA 94305-5723; email: Disclosure: Lembke reports no relevant financial disclosures.




Medical marijuana cannot replace opioids to relieve cancer pain; however, it may be considered as an adjuvant pain-relief method to reduce excessive opioid use — opioid sparing — in states where legal.

Jai N. Patel, PharmD, BCOP
Jai N. Patel

Different compounds in marijuana have different actions in the human body. Delta-9-tetrahydrocannabinol (THC) appears to cause the “high” reported by users, but also can help relieve pain and nausea, reduce inflammation and increase appetite. The number and size of studies that have evaluated the effects of marijuana on cancer-related pain is small, thus the evidence is limited to support its routine use in clinical practice, minus the regulatory barriers. Nonetheless, some data suggest use of marijuana in combination with opioids can help reduce opioid requirements. Practitioners are aware some patients utilize various forms of marijuana and swear by its positive effects on pain, nausea, appetite, anxiety and other cancer-related symptoms. It is important to realize there are differences in response based on route of administration, dose and ingredients. Thus, increased education for providers on marijuana’s effects, both positive and negative, is critical.

Opioids are the mainstay treatment for cancer-related pain and will be for the foreseeable future, despite the opioid epidemic. Although regulations are in place to limit opioid use broadly, these have generally excluded patients with cancer. Nonetheless, this has impacted them. Although the proportion of patients with cancer taking an opioid prescription (43%) has not changed from 2016 to 2018, there has been a substantial increase (16% to 41%) in those unable to obtain their opioid medication at the pharmacy. Doctors have indicated their treatment options were limited by laws, guidelines or insurance coverage. Patients with a legitimate medical need must be able to access opioid medications for management of their pain, and providers should be able to educate patients on risk for opioid misuse.

Increased federal funding will help identify potentially new targets or nonopioid analgesics that are as effective as, or even better than, opioids. Some of this funding may even go to better understanding the effects of marijuana on cancer-related pain. However, until then, safe administration of opioids with close monitoring should remain the gold standard for treating moderate-to-severe cancer-related pain, as these are the only pharmacological options with sufficient level of evidence. Studies have now shown that opioid overdose and opioid-related death is very low in patients with cancer, further suggesting that opioid use is generally safe to treat cancer-related pain if appropriate management and monitoring strategies are in place.

There is a dire need for increased education on the use of marijuana for cancer-related pain, screening for opioid abuse/misuse, and nonpharmacologic methods of managing cancer-related pain, such as acupuncture, massage, physical rehabilitation, etc. Although opioids remain a primary treatment option, a multidisciplinary approach is mandatory for safe and effective management of cancer-related pain. Clinicians must be aware and educated on these various approaches.

Jai N. Patel, PharmD, BCOP, is chief of pharmacology research and associate professor in the division of hematology/oncology at Levine Cancer Institute at Atrium Health. He also is a HemOnc Today Editorial Board Member. He can be reached at Disclosure: Patel reports no relevant financial disclosures.