Doctors, what are the long term side effects of taking phenobarbital for decades?

Dependence: The biggest problem with taking phenobarbital for decades is that you develop dependence and would need to be tapered off of it. It is a barbiturate used as a sedative but in the past was commonly used to treat seizures. I have had patients that have been on this for decades with controlled seizures with no long term side effects. If someone has been on it, it may be safer to keep them on it.