My Epileptologist keeps a report on how I react with the medication. Starts me on a certain dosage. Next visit the Dr. will have me do blood work to check my levels . Figure out whether or not my meds need to be increased.

Once I’ve been on my maxed amount of medication and they still aren’t working , the Dr. will put me on a different medication brand.

The only way that I can think of this happening is if they need to make a change in the dosage or when you start a new med. If you were having seizures after being on a med for a while they wouldn't class it as a side effect.

ok, storytime.... long ago (kid age) the other meds did nothing (no good but no bad). i switched to dilanten and depakote. immetediately i had clusters of seizures and had to get off of um asap. had to switch to a different med. but yet agian, dr will get me on the keto diet and that really helps controls my seizures. that and weed.
i get your consern. drs will guess what is wrong with you. but the good thing is,drs have knowledge. thay know all the meds and treat minimize the side effects. 9-10 times it works. even me, a med resistant guy... drs found a way to control the seizures by alternitive meds.

Worry not bout sides as Randy said Dr moniter body's reactions. More important is how they they help the seizures. Funny when see TV ads even for OTC meds the sides sound scary.

Maybe the dosage needs to be adjusted. If you have been taking the drug for about 6 weeks and you are still experiencing seizures, then it could be conflict with another medication you are taking. Or your vitamin supplements. Also diet. Keep a diary on what day and when your seizures are happening so you can discuss it with your neurologist.