Keeping medical cannabis out of the hands of children is basically following the same steps that parents already utilize for keeping harmful chemicals and other prescription drugs away from children.
First thing is to make sure that your children know that these products are medicine. If you are using edibles that look like cookies, make sure that they are well marked and make sure that your children understand that something with this symbol means that they don't eat it.
You know that you have taught your children this already, unless your children eat a lot of bleach, but hopefully, they have heard your warnings and said that pharmaceuticals and chemicals are not for them.
With cannabis, especially if you have teenagers in the house, they may not get into it on accident, they may be looking for it, and so again, I would be very up front with your children, that it's in your home, explain to them that it's for medical use, and that your medical history and concerns are a private matter in the family. This is not something that you want your children telling other kids at school about, or other items, in the same way that you wouldn't want them talking about any other medications that you're on.
You should also, if you have teenagers in the house, put your cannabis in a locked box, hide it out of sight, and be conscious of where you use it. But again, keeping cannabis out of the hands of children is the same as keeping prescription drugs or other harmful chemicals, and it's definitely the possibility of children getting into these substances isn't a reason to keep it illegal for everyone. Now, we hear of a lot of cases of children bringing cannabis to school or going to the emergency room for eating too much of it, and so, as a parent, you do need to be conscious about where you put it.
If your child does ingest cannabis, they are going to feel the same side effects that you would as an adult, and again, they are not going to die, but they are probably going to be very uncomfortable for the next couple of hours, so just be a conscientious user and make sure that your children don't get into any of your medicines or harsh chemicals.