What are the effects of Phenobarbital on babies?

My 7 month old baby boy, Benji, was recently diagnosed with epilepsy (simple partial seizures, occipital lobe, manifesting as a turn of the eyes and head to the left, sometimes with a smile or vocalization, daily and very frequent). We had been told before that the eye movements were nystagmus until a long EEG revealed that they were seizures.

Benji started Phenobarbital several weeks ago and the seizures have not stopped but are a bit less frequent. The dosage has been increased several times and he is now taking 60mg daily. I've noticed that he's a bit less responsive and more lethargic, and the only information about side effects from his doctorsrefer to sleepiness that eventually subsides.

My question is this: What effect will the medication have on his brain activity? Will it take longer to learn or develop? It may sound crazy, but I've noticed that his head feels cooler and sometimes clammy (his head is often resting in my arms while he nurses). Is this normal? And if brain activity is suppressed, how do I know if it is better for him to be on the medication?

Thanks for taking the time to read my post.

~ Benji's Mom