Do you titrate anti-seizure medication doses in the setting of high or low serum drug levels if patients remain seizure free?

The short answer is "no", especially in the setting of high levels, if there are no side effects reported, and other appropriate surveillance labs look good (such as CBC and LFTs for VPA). The only case where I might increase the dose slightly would be for a below-therapeutic range level in a seizure-free patient where I recently switched to the new drug for another reason. For example, if I saw a patient on CBZ for years who had newly discovered osteopenia and I switched them to lamotrigine, but their level was below the lower limit of the therapeutic range after the switch, I might increase that dose a bit to get them into that lower level of therapeutic. However, I always tell patients that these ranges are all relative and we never know...

I fully agree with the above answers that we treat patients and not their numbers, and to be honest, I never check levels on the "newer" medications anyway, unless I am suspecting the patient is not taking the medication (it really has not happened). I have not increased lamotrigine even during pregnancy in a lady who is on a minimum of 400 mg a day, and I never had a problem with that (thank God). Now, I know many will disagree with this. I am certainly NOT recommending that; it is just what I do as I take each case individually, especially when it comes to ladies during fertile years.