Short Story: Start with what is available. Start with a small dose. Observe the results. Make changes slowly. Start low, go slow is the favorite motto from parents who came before me. This is so hard when your child is having a lot of seizures. You just want them to stop! But you want to find the best dose. This may mean accepting there will be seizures, but hopefully less intense and shorter. This is the case with my daughter. If you go over the best dose this can also make the seizures worse, especially if you are still on other medications. Observe, monitor, and adjust. In my experience, most people do not need much.
Update: There are many companies selling high CBD hemp (<.3% THC) oil nationally and internationally, this may be a good place to start but realize many kids (with and without seizures) benefit from some percentage of THC. Try to choose an oil made from the whole plant and not just a lab extraction of CBD.
Long Story: I know how important it is to have an exact dose. After 5 failed medications, titrating up and down with small increments for years ingrained the importance of dosing in my brain. Calculating mg/kg and figuring out how much medicine was in a ml or oz was constantly making me question the dosage of any medication. The same was true when we started Medical Cannabis in Oregon. All of the oils had different info on the labels. Some were in percentages, others in mg/ml, and some in mg/bottle. So I did a bunch of headache math to figure out what I was giving my kid. And then I realized it didn’t matter.
Calculating a dose down to 1mg is possible, just not as pinpoint accurate as you want it to be. And it doesn’t matter. Dosing by observation, in my experience, is a much better measure than a number that may be skewed by the standard deviation of lab results. (Even state sanctioned labs results can vary significantly). It is useful to get a ballpark figure if you can. So when you switch medications, you can find a similar product if you wish or find one with more or less of a certain cannabinoid. It also helps you determine if a product is worth the money you are paying. One bottle may have 10mg/ml while another has 40mg/ml. The bottle with 10mg/ml should cost less, all other factors equal. See Calculating a Dose.
What to look for in a cannabis product: outdoor, organic, local, method of extraction, cannabinoid fingerprint with your preferred amounts of CBD and THC. If you can get all of these you hit a home run.
If you can’t confirm any of this, work with what you have.
Sometimes a tolerance seems to build. You may have read that some parents of children with seizures give their child a “break” after a few weeks to avoid having to constantly titrate up. This is why we use a very small dose and avoid the titration altogether. Of course there are exceptions, cancer, being one. If you are trying to stop and reverse cancer there is a certain amount of increase suggested by consultants in this field.
For most people, even adults, using a small amount is enough. A friend who is suffering from degenerative nerve disease uses 2 drops of the exact medicine my daughter, age 7, uses. Starting low and going slow when medicating is the key to not overdosing. You may not get the anticipated results but may get some very nice side effects like helping behavior, reducing anxiety, and helping in cognitive gains. See Endocannabinoid Systemfor more info.
If you are in a state or country where cannabis is still illegal, research the rest of this website and read forums such as Pediatric Cannabis Therapy on Facebook. Education helps everyone involved in the process.