CBD is neurological and can tell your brain cells that are triggering anxiety to 'calm down'. This is also why it's a great anti-inflammatory. CBD won't be a dangerous addition to pharmaceutical medications.
Tinks to be on the safe side, talk to GP. But the link i provided is to 'better quality' CBD products. You can talk to hemp botanics about any products and they'll be happy to help. Another company (where you can get free samples) is CBDbrothers. These are cool guys who care about the medicinal affects CBD can have on people.
Cancer and chemo patience are recommended to take CBD or other cannabinoids to help pain, anxiety, stress and depression also appetite and fatigue. They're usually on a mad variety of drugs and there is (almost) never a reaction between CBD and the pharmaceuticals. But talk to your doc if you want to be sure. Better safe than potentially sorry.