From what I've read on a couple studies about it, it appears higher doses of naltrexone (100mg) actually enhance the effects of thc. While lower doses (25mg) blunt the effects a bit.
Naltrexone is an opioid antagonist. It blocks mu receptors in brain. Cannabis does not effect mu receptors. So the answer is you can take your naltrexone and cannabis together without any trouble. I’ve been on Revia (naltrexone) 50 mg for the whole year and smoked pot every day.