My guess is that strains/ products with more CBD and less THC and CBN would probably be better. Zonegran and Vimpat are both anti-Seizure medications and for these class of meds, dizziness /sleepiness/ & or loss of balance can be issues for some patients. From a safety standpoint I would probably take med cann (regardless of cannabinoid profile) at a different time than these two medications to decrease risk of fall and accident. As for the chemo-therapy agent Lomustine, I would probably make sure with your oncologist that cannabis isn’t effecting liver enzymes that effect lomustine’s overall metabolism. If you are fighting cancer, I would say avoid smoking/ combustion of cannabis as potentially carcinogenic compounds are formed. I hope these tips help!