Cannabis Use While Taking Naltrexone
Yes, a patient can smoke cannabis (seeds/marijuana) while taking naltrexone, as there are no absolute contraindications to this combination, though naltrexone may actually reduce cannabis use and its subjective effects.
Pharmacological Interaction and Safety Profile
Naltrexone does not create dangerous drug interactions with cannabis. The primary mechanism of naltrexone is mu-opioid receptor antagonism, which does not directly interfere with cannabis's action on cannabinoid receptors 1. There are no documented safety concerns regarding cardiovascular effects, seizure risk, or other serious adverse events from combining these substances.
Key Safety Considerations for Naltrexone Use
The actual contraindications for naltrexone therapy are distinct from cannabis use:
- Current opioid use is the absolute contraindication - naltrexone will precipitate severe withdrawal in opioid-dependent patients and block pain relief from opioid medications 1, 2, 3
- Liver function monitoring is required - baseline and every 3-6 months, as naltrexone has been associated with hepatic injury at supratherapeutic doses 1, 3
- Uncontrolled hypertension is a contraindication when naltrexone is combined with bupropion (as in naltrexone-bupropion ER formulations), but not for naltrexone monotherapy 2, 3
Potential Therapeutic Effect on Cannabis Use
Emerging evidence suggests naltrexone may actually reduce cannabis consumption rather than being contraindicated with it:
- A double-blind, placebo-controlled study demonstrated that naltrexone maintenance (50 mg daily) significantly reduced both active cannabis self-administration and positive subjective effects in daily cannabis smokers 4
- Participants receiving naltrexone had 7.6 times lower odds of self-administering active cannabis compared to placebo (95% CI: 1.1-51.8) 4
- This reduction in reinforcing effects extended to cannabis use in natural settings outside the laboratory 4
Clinical Implications
For patients with substance use disorder taking naltrexone who also use cannabis:
- Cannabis use does not require discontinuation of naltrexone therapy - there are no safety concerns that would mandate stopping the medication 4
- Naltrexone may provide an additional benefit by reducing cannabis consumption and craving, though this is not its primary indication 4
- Monitor for naltrexone's intrinsic side effects including decreased appetite, gastrointestinal upset, and headache, which are unrelated to cannabis use 4
Important Caveats
The critical distinction is between naltrexone monotherapy versus naltrexone-bupropion combination products:
- Naltrexone-bupropion ER has additional contraindications related to the bupropion component, including seizure disorders and abrupt benzodiazepine discontinuation 2, 3
- These bupropion-related contraindications do not apply to naltrexone monotherapy 1, 5
- Cannabis use itself does not interact with either formulation from a safety standpoint 4
Ensure the patient is not using opioids concurrently, as this remains the primary contraindication regardless of cannabis use 1, 2, 3.