Infantile Spasms

My son Tommy was diagnosed with Infantile spasms at 5 months old. We noticed "twitches" that our pediatrician told us may be primal reflexes. After a few more days of seeing my son having "jack knife" seizures where his head would drop and his arms would fly up and his knees being pulled to his chest - I knew something was definitely wrong. My husband video taped the seizures and we brought the tape to our peditrician to view. He immediately suggested we go to see a neurologist and have a EEG done. We did. That same day our son was admitted to the hospital for one week for many tests. He had a spinal tap to rule out any type of in fection. Then he had a CAT Scan, an MRI, many blood tests as well as X-rays done. Everything came back normal. My son shows no sign of mental retardation and seems to be on track developmentally. He was put on ACTH for one month with no change to his spasms. He is also taking Kolonopin. He also has acid reflux and is taking Zantac for that. We are now on Topamax. It has been about 2 weeks and we see little improvement. Tommy has head bobs throughout the day, he has clusters of spasms when he wakes from naps and in the morning, he also jerks when he is drifting off to sleep. He is now being waken at night from the seizures. We feel helpless. We heard that the longer we take to stop the spasms the greater the chance that Tommy could stop developing or take steps backwards in his development. Our neurologist suggested tryung a drug from Canada called Vigabatrin or Sabril. We are from the US and it is not approved here yet. I have done some research on this drug and it seems dangerous for long term use. We just don't know what to do. Any advice anyone has will greatly be appreciated. Thank You!