A good friend of mine had a serious seizure. How well does medication prevent further seizures?

It depends on the underlying problem.

For most people medication makes a huge improvement. I knew a young man who had frequent seizures, and on medication they stopped completely.
I knew an elderly man who suffered seizures his whole life. He had one nearly every day. He was on the strongest medication attainable.
It can be a dream come true, but it is not always. Nobody can be certain until it is tried. Some people have to go through a number of med changes before they find what will work best for them.

A sudden seizure can be from a variety of reasons. She needs a x-ray of her head, and possibly a cat scan, before anything else. An intracranial mass needs to be ruled out…

Phenobarbital can be very effective, but takes some time to work itself into the system. Often times, the dosage will need to be changed. A patient needs enough to stop the epilepsy, but not so much it negatively effects the liver…

I hope it was just an anomaly.

Because each person is different, this is a trial and error process. It takes time to find the correct dosage.

She had two CT scans in one week, I guess to look for a tumor, but none were found. She did not say she had been given any kind of medication but rather was told to stop all medications! Including her Losartan for blood pressure and her sleeping pill. I told her she could not stop her sleeping pill suddenly; that it was dangerous to do so. Then she said she had been taking two per night, could not sleep so she took one and was up then down all night long with nightmares. I think it was Lorazepam. Ten milligrams I believe. After losing her drivers license for three months over this her husband told her, “Walmart is just a five minute drive; you can continue to go there and back.” I actually believe many spouses would take this attitude due to their close proximity to the store. Imagine shopping a day after coming home from the hospital after having a seizure. Not me!