I am not breathing.

I am lying on a procedure table in my doctor's office, passed out, but can still hear what is going on around me.

I am lying there, passed out and not breathing, because of the pain.

Migraine. This one was triggered by the requirements that I neither eat nor drink before a routine, midafternoon medical test. The predictable headache came early and burst sometime before the procedure, growing until the intensity finally shut my body down.

For a few seconds, I feel finally free of the terrible ordeal of breathing.

Suddenly someone slaps an oxygen mask over my face. I am jerked back. I also feel a needle in my arm pumping in the slow warmth of narcotic painkiller.

"It's temporary," the doctor tells my husband. "But it will get you home."

For 30 years, migraines like this have been a way of life. What started as an occasional headache during my first pregnancy has become an unstoppable headache that routinely courses into viselike pain, vomiting, and blackouts. I have been hospitalized, medicated, and trained to eat nothing desirable and exercise relentlessly. But the headaches still come.

And that has compelled me to try an experimental solution. Botox. Not for cosmetics. Botox for migraine. It is a treatment not yet approved by the Food and Drug Administration but well into the process. A major study on the drug will be released this week in Philadelphia. I hope Botox will help people like me for whom nothing else works.

Why Botox? Because of the way it works. Famously known as the vanity drug for aging baby boomers, Botox can temporarily paralyze muscles and nerves, not only diminishing those nasty frown lines, but also, doctors report, helping to diminish chronic migraines.

Researchers are finding that injecting Botox directly into the nerve can interrupt pain signals between the skin nerves and the nerves around the brain. But they warn it's not a cure and doesn't work for most migraine sufferers.

Originally FDA-approved for uncontrolled eye blinking and crossed eyes, Botox found its calling as a cosmetic drug. And that's where the migraine story begins, because cosmetic patients with migraines who got Botox found their headaches virtually disappeared, said Diamond Headache Clinic associate director Frederick Freitag in Chicago.

This was big news. Occasional low-level migraines attack about 30 million Americans. Chronic and high-frequency migraines affect an additional six million Americans. And other migraines affect a half million more, making the total about 37 million. There are no biologic markers or cures. The drugs that exist are partial solutions. Americans spend about $3 billion a year on migraine treatments, and companies lose about $13 billion in lost wages and worker sick time.

But Botox?

Botox is a refined biological product containing a minute amount of botulinum toxin, a protein made by the bacterium Clostridium botulinum. These are not the botulinum spores that occur naturally and cause botulism poisoning. Rather, Botox comes from a rigorous manufacturing process that distills the active ingredient.

Skeptics abounded.

"I didn't believe it," said Stephen Silberstein, director of the Thomas Jefferson University Hospital Headache Center.

But Allergan, the largest maker of Botox products, was tantalized. It contacted the National Headache Foundation, inviting doctors to talk about Botox's potential as a migraine treatment.

Freitag was one of those who answered. What he discovered was that Botox's greatest potential might be for the so-called chronic and high-frequency migraine - the six million or so people who have a migraine almost all the time. He did not see the same potential in the episodic migraines suffered by 30 million people.

"The folks at Allergan said, 'Thank you very much, Dr. Freitag,' and sent me packing," he said. "They were looking for me to say, 'Oh, this is going to be the next end-all and cure-all for migraine headache,' and they were looking at 30 million people. The cash and dollar signs were just ticking. So I was a big letdown."

But both Freitag and Silberstein persisted, joining the arduous trials of Botox to see if it might help more than a few cosmetic patients. Silberstein, who receives an honorarium from Allergan and is on its advisory board, wrote the lead paper in the first clinical trials.

"Many of the things we do in our day-to-day practice do not result in relief for our patients," Silberstein said. "Basically, we're still hitting 50 to 60 percent in most of our treatments."

Several studies resulted. By far the biggest will be announced Saturday at the International Headache Congress in Philadelphia. They are the results of Allergan's two Phase III studies involving more than 3,000 patients. These have been submitted for publication to the Lancet, a British journal, and to the FDA for Botox's approval as a migraine medicine.

Experts say they will most likely show what Freitag first told Allergan 13 years ago: Botox works best for one group - those with chronic and high-frequency migraines.

He estimates that about half that group could benefit from Botox, and at least a million would be both eligible and interested in using Botox.

In that group, Silberstein has found an 80 percent improvement. That means if you have a headache 30 days a month, Botox can cut that to six days.

Not all are convinced.

Adam Shuhendler, a Ph.D. candidate in pharmaceutical sciences at the University of Toronto, published an analysis of studies involving 1,601 patients treated with Botox for episodic migraine.

He says its effectiveness is unproven for chronic migraines. And since Botox seems to affect some groups dramatically while doing little for others, he wonders if the results can be duplicated in doctors' offices.

Other questions remain: Is Botox safe and cost-effective?

While its approved uses in the United States are narrow, Botox has 21 usages in 80 countries. And, it has been the subject of more than 50 studies. In this country, it has "off-label" uses, meaning it can be used for nonapproved treatments like migraine and juvenile cerebral palsy. Doctors can prescribe drugs off label at their discretion.

But Botox-related products are refined toxins. Serious problems - from difficulty breathing to aspiration pneumonia to death - can result if the toxin escapes the injection site and settles in the swallowing or breathing area. This is most likely to occur in the very frail - either sick children or the elderly, whose conditions require huge doses.

If it were strictly used for FDA-approved treatments, says Sidney Wolfe, director of Public Citizen's Health Research Group, "you wouldn't have many adverse effects." But Botox off-label use is huge, he said.

Allergan has admitted it received a federal subpoena last year focused on how it had promoted Botox. Drug firms are not allowed to promote off-label uses. The company says it is cooperating.

After Wolfe's group filed a petition in early 2008, the FDA last month ordered Botox products to carry a "black box" label clearly explaining the risks. In its announcement, the FDA noted that no serious adverse effects were found in approved cosmetic uses.

Side effects have also been mild in studies of migraine patients. "It's very safe," said Freitag, who said he had treated 1,000 patients with Botox.

But cost can be an issue. Allergan charges $525 per 100-unit vial, and four such vials are needed each year.

My insurer covered most of the $2,100 cost, not including doctor visits, but other insurers don't since it is still off label for migraine.

By contrast, new migraine drugs can cost a lot more.

My insurance pays about $5,000 a year for my migraine drugs while I cover about $1,000 out of pocket.

So, will Botox work for me?

I arrive at the Jefferson University Hospital Headache Center with a headache. I've had it for months. Today it's manageable, meaning that I've taken enough medicine to function.

As I take off my jacket and prepare for the injections, I am mindful of what the studies show - the results take time, fewer headaches occur, and those you get are less severe. It's not a cure.

And I am thinking about all the lost days, the missed graduation, the frantic hospital trips, and all the drugs I have taken over the years - the antidepressants, anticonvulsants, beta blockers, herbs, anti-inflammatories, painkillers, and those gold-plated meds, Zomig and Amerge, which cost a small fortune and that insurers always fight.

Silberstein, who's giving me the treatment, takes out the long needles and asks if he is probing a painful spot. "Yes," I say, and he quickly injects me around my neck and above my eyes.

It's over. I get up to leave. "How do you feel?" he asks.

I'm surprised by the question. It all happened so quickly. But I notice something different. Something is missing.

The headache is gone. There is no slow warmth, no confusion, none of the side effects of other drugs.

I know there can be an "acupuncture" effect, which is the release of pain because of the needle in the nerve, and that may well be what is happening. But I do not care. As I drive home, I am a little breathless and giddy with relief.

The next day, I notice my left eyebrow droops a bit. The injection sites are swollen and a small bruise lies between my eyes. But my frown lines have vanished. Still, I feel exhausted, listless, as if I were getting the flu.

By the next day, I am fine. And the eyebrow corrects itself.

It's been more than five weeks since that day and I have had some headaches, but they haven't been as bad or as frequent as before. And I had two "almost" migraines, and one that broke through. But none was as bad as what I had been getting. Not even close.

For now it's working.

Contact Elizabeth Duff at kstark@phillynews.com.