Any migraine sufferer dreads the onset of another bout -- the intense pain, nausea, vertigo and other symptoms that can knock you out of action for days.
Now doctors are encouraged by a new class of drugs that can prevent a migraine from even starting. They are the first drugs specifically designed to prevent migraines, and tests show they can help a significant number of sufferers.
They're being featured at a meeting of the American Headache Society that starts this week in Washington, D.C.
"I think that these are truly designer drugs for migraine," said Dr. Richard Lipton, director of the Montefiore Headache Center at the Albert Einstein College of Medicine in New York.
More than 36 million Americans suffer from migraine attacks, according to the American Headache Society. Of these, about 4 million have chronic migraine and suffer headaches for 10 to 14 days a month.
Migraines are not ordinary headaches and while some people are helped by over-the-counter drugs such as ibuprofen, others turn to stronger prescription drugs such as sumatriptan and ergotamine drugs, which constrict the blood vessels in the brain and can cause dizziness or nausea.
Botox can also prevent migraines for some people, but a large percentage of sufferers are not helped by anything. And there's a nerve-stimulating headband on the market to prevent migraines as well.
"For people with migraine this new class of compounds is extremely effective and has surprisingly few side effects," Lipton told NBC News.
The drugs are aimed at a compound called calcitonin gene-related peptide or CGRP. Four different companies are testing drugs that affect CGRP: Alder Pharmaceuticals, Amgen, Eli Lilly and Company, and Teva Pharmaceuticals.
CGRP is a neurotransmitter -- a message-carrying chemical.
"We've known for a long time that CGRP was involved in the mechanism of migraines, so during migraine attacks you can measure elevation of CGRP in the blood of the person having the migraine," Lipton said. "If you treat it, CGRP blood levels fall."
The new drugs interfere with CGRP. Some are monoclonal antibodies -- lab-engineered immune system proteins that are designed to attack a specific target. In this case, it's CGRP.
The downside of monoclonal antibodies are they usually must be injected or infused. And they are pricey - current monoclonals used to treat cancer, for instance, cost upwards of $10,000 a month.
But it's not certain that's what these new drugs would cost and the benefits to migraine sufferers could outweigh any cost, especially if they only have to be given every few months.
"The potential of these new compounds is enormous and gives us real hope that effective specific treatments for migraine may be on the near horizon," said Dr. Peter Goadsby of the University of California, San Francisco, who's been testing some of the drugs. "The development of CGRP antibodies offers the simple, yet elegant and long awaited option for migraine patients to finally be treated with migraine preventives; it's a truly landmark development."
It can be tricky to test a drug to prevent migraine. The companies have made the goal cutting the number of attacks in half. Some of the drugs appear to have done that, although they are still in the testing stage - stage II trials, which are intermediate trials in between testing a drug for safety alone and testing to see just how well it works, and at what doses, in larger numbers of people.
The companies reported data on several hundred patients who tried their drugs out at various doses. A few people saw their migraines virtually disappear, although it is not clear for how long.
"It's good news for many patients and it's absolutely spectacular for patients whose headaches stopped altogether," Goadsby said. "It's just great news to have a new class of medicines for a common condition."