Three controlled trials demonstrated that oral THC has variable effects on appetite stimulation and weight loss in patients with advanced malignancies and human immunodeficiency virus (HIV) infection.[32] One study evaluated the efficacy of dronabinol alone or with megestrol acetate compared with that of megestrol acetate alone for managing cancer-associated anorexia.[40] In this randomized, double-blind study of 469 adults with advanced cancer and weight loss, patients received 2.5 mg of oral THC twice daily, 800 mg of oral megestrol daily, or both. Appetite increased by 75% in the megestrol group and weight increased by 11%, compared with a 49% increase in appetite and a 3% increase in weight in the oral THC group after 8 to 11 weeks of treatment. These two differences were statistically significant. Furthermore, the combined therapy did not offer additional benefits beyond those provided by megestrol acetate alone. The authors concluded that dronabinol did little to promote appetite or weight gain in advanced cancer patients compared with megestrol acetate. However, a smaller, placebo-controlled trial of dronabinol in cancer patients demonstrated improved and enhanced chemosensory perception in the cannabinoid group—food tasted better, appetite increased, and the proportion of calories consumed as protein was greater than in the placebo recipients.[41]

Did you get an answer for this? I have the exact same scenario. I'm treating my TN with Tegretol, and recently tried CBD. I think I took too much and there are some weird drug interactions with Tegretol and I felt quite stoned....was alone and talking to myself in my head thinking I was Einstein. It freaked me out a bit but I think I took too much. I'm trying lower doses again as recently my TN seems to be resisting the meds, although I have had a lot of emotional stress, which seems to be a trigger. Thanks!! Anna