Codeine is a prescription opioid used to treat moderate pain and, in some cases, cough. Like other opioids, it can carry serious risks, especially if not taken as directed.
Cannabis is also commonly used for pain management. Surveys reveal that some patients report using it for this reason under medical guidance.
Because both substances may affect pain, some might wonder if they can be used together. However, the way opioids and cannabis interact in the body is still being studied. Combining them may increase the risk of side effects. In this article, we explore what current research says and why it’s important to speak with your doctor before considering mixing the two.
What Is Codeine?
Codeine is an opioid medication that’s commonly prescribed to treat moderate pain, chronic coughing, restless leg syndrome, and sometimes diarrhea.
Opioids have been used for centuries to relieve pain. Historically, they were derived from the poppy flower. While some modern opioids are synthetic or partially synthetic, codeine is still derived from the sap of the opium poppy.
Codeine is a prodrug of morphine, meaning it’s chemically similar to morphine but inactive until the body’s metabolic process converts it to morphine within the body. Codeine is also regularly used in conjunction with other medications.
Opioids are a classification of drugs that bind to opioid receptors in the brain. When opioids bind to these receptors, they block pain signals. They also trigger the release of dopamine and endorphins, which manipulate the brain’s reward systems. This is why there’s such a high risk of addiction associated with these medications.1
Opioid abuse is an epidemic in the United States, responsible for thousands of overdose deaths yearly. In fact, in 2022, 81.8% of overdose deaths in the U.S. resulted from opioids. In addition to developing a physiological dependence on opioids, people can develop a physical tolerance, meaning they’ll need more and more of the substance to get the desired effects. These increasing amounts lead to higher risks of complications and overdose, making extended use or misuse of opioids a serious public health threat.
Combining Cannabis and Codeine: What the Latest Research Says
Using cannabis and codeine together may seem appealing to some people seeking pain relief, but combining the two substances carries real risks. Similarly, research on their interaction remains limited.
Codeine and cannabis affect the body differently and come with different safety concerns. Cannabis, especially in higher doses, may cause:
- Anxiety or paranoia
- Drowsiness
- Appetite changes
- Dry mouth
- Distorted sense of time
- Short-term memory issues
Codeine is a prescription opioid with much more serious side effects, including:
- Nausea, vomiting, and stomach pain
- Dizziness and confusion
- Breathing difficulties
- Irregular heartbeat
- Muscle stiffness or twitching
- Sexual or hormonal changes
- Rash or severe itching
- Seizures
More severe reactions may signal a dangerous interaction or overdose and should be addressed by a doctor immediately.
Early research shows that cannabis and opioids may influence each other. Animal studies suggest that cannabinoid and opioid receptors are located in the same areas of the brain and spinal cord. Some studies found that THC can increase natural opioid levels in the body, while others suggest that blocking opioid activity may reduce the effects of THC. However, findings are mixed, and most of this research hasn’t yet been confirmed in human trials.
One area of concern is serotonin syndrome, a potentially life-threatening condition linked to excess serotonin in the brain. While rare, combining substances that influence serotonin — like some opioids and THC — may increase the risk. Symptoms can include agitation, fever, muscle stiffness, seizures, and, in extreme cases, coma.
Is Cannabis a "Safer Option" Than Codeine?
Codeine has long been used to treat pain, but it also comes with high risks. It can be habit-forming and, like other opioids, contributes to overdose deaths in the U.S. every year.
Cannabis, on the other hand, tends to have milder side effects and a much lower potential for dependence. There are no confirmed cases of fatal cannabis overdose, and in some states, opioid use disorder is a qualifying condition for medical cannabis programs.
Some studies suggest cannabis may help reduce opioid use or act as an alternative for certain patients. For example, research has linked the presence of legal cannabis dispensaries to lower rates of opioid overdose. Still, more clinical trials are needed to confirm whether cannabis can safely replace or reduce opioid use.
Can Opioid Use Disqualify You from MMJ Card Eligibility?
Opioid use will not disqualify someone from medical cannabis. In fact, in many cases, it’s just the opposite.
Some states recognize cannabis as a potential alternative to opioids, and some even acknowledge it as a possible treatment for opioid use disorder. Both New York and New Jersey treat opioid use disorder as a qualifying medical condition for cannabis. Pennsylvania acknowledges opioid use disorder as a qualifying condition when conventional treatments have proven ineffective.
Are You Considering Using Cannabis and Codeine?
Combining cannabis with any substance or medication carries its own risks. Cannabis research is still in its earliest stages, and there is a lot that researchers still don't know. That leaves the door open for unexpected interactions with other substances. If you are considering combining cannabis with any other substance or medication, speak to your doctor for proper medical guidance.
Likewise, stopping the use of a prescribed medication can lead to unintended consequences. Many medications take time to build up in the body. Stopping suddenly can cause unpleasant and potentially serious or even fatal side effects. If you'd like to stop using or replace a medication, you need to follow the guidance of your medical provider to make any approved adjustments safely.
References
- Salio C, Fischer J, Franzoni MF, Mackie K, Kaneko T, Conrath M. CB1-cannabinoid and μ-opioid receptor co-localization on postsynaptic target in the rat dorsal horn. Neuroreport. 2001;12(17):3689-3692. doi:https://doi.org/10.1097/00001756-200112040-00017 ↩︎
The information in this article and any included images or charts are for educational purposes only. This information is neither a substitute for, nor does it replace, professional legal advice or medical advice, diagnosis, or treatment. If you have any concerns or questions about laws, regulations, or your health, you should always consult with an attorney, physician or other licensed professional.
