 |
| More than twice
as many women as men suffer from migraine because
of the involvement of hormonal factors. |
Ask questions ?
Share views !
Share difficulties with your conditions !
Meet people with a similar condition !
Your not alone !
International
UK
USA
Click logo for forums
|
|
|
|
Migraines strike unexpectedly, disrupting lives. Many
long-planned family celebrations
have been ruined when one of the main
participants ends up spending the whole day in
a darkened room with a throbbing headache and nausea.
In fact, about 25 million working days
are lost to migraine every year.
Many people never visit their doctors for help
with migraines, preferring to use over-the-counter painkillers and anti-inflammatory
medicines such as aspirin and ibuprofen. For those who do consult a doctor,
the first suggestion might be to make some lifestyle changes. This is
because migraine attacks can be sparked off by stress, caffeine, exercise,
or changes in eating or sleeping patterns. Recognising personal triggers
and avoiding them wherever possible is a good start to dealing with migraine.
People who still have one or two migraines a
month will generally turn to medication. In addition
to painkillers and anti-inflammatory medicines, doctors can prescribe
products specifically
designed to deal with migraine – primarily the ergots and triptans.
For people who have more frequent or particularly
severe migraine attacks, there are also preventive treatments. Many of
these, such as beta blockers
(used to treat high blood pressure), antidepressants
and anti-epilepsy drugs, were developed for completely different uses.
Causes of migraine
Migraine is one of the oldest disorders known
to man. The Babylonians described migraine in 3000
BC; in 150 AD the Roman physician Galen coined the
term hemicrania to describe the one-sided nature of migraine. Over the
following centuries the word “hemicrania” gradually evolved into “migraine”.
Despite recognising the condition for so long, we have only recently
begun to understand what causes migraine and to use
this information to develop specific
treatments.
 |
| Migraines can be
triggered by foods such as chocolate, wine, coffee
and cheese, amongst others. |
Trigeminovascular theory
The most popular explanation for migraine, which has been developed
over many years by studying animal models of migraine, is called the
trigeminovascular theory. This theory blames environmental triggers such
as bright lighting for sparking off a sequence of events in the brain
stem - the bit that joins the spine to the rest of the brain. Some of
these events are responsible for the aura, sensitivity to light and sound,
and the feelings of nausea. The headache itself is the result of the
large trigeminal nerve being activated to send out chemical messengers
that cause blood vessels in the brain to expand. This expansion stretches
and squeezes nearby pain receptors, parts of cells that send pain messages
to the brain.
Migraine
- Treatment & needs
People have been trying to treat migraine since medical records began.
The Egyptians recommended tying a clay crocodile with herbs in its mouth
to the patient's head. Other early remedies included blood-letting and
drilling a hole in the skull to release evil spirits.
| Ergot, extracted
from a fungus, is just one of many naturally-occurring
compounds that have given rise to modern medicines |
Migraine treatment
became more scientific in the 19th century when
physicians began to use ergot. Ergot, which is extracted
from a fungus, contains a mixture of
chemicals. Some cause blood vessels to constrict
and consequently turn off pain-producing nerves in
the head. These properties gained ergot
recognition as a useful treatment for migraine,
albeit one with serious flaws. Its effects were unpredictable
owing to the many biologically
active compounds it contains: ergot, as well
as treating migraine, can cause convulsions, gangrene,
hallucinations and even death. Luckily,
in the 1920s, chemists identified and isolated
the chemical ergotamine from ergot. Ergotamine has
the useful properties of ergot but fewer side
effects. Since then several ergotamine variants
have become available for the acute treatment of
migraine and are still prescribed today.
In 1972, UK scientist Pat Humphrey initiated
a migraine drug discovery project at Ware in Hertfordshire for the British
pharmaceutical company Glaxo. His starting point was the observation
that methysergide, an anti-migraine agent related to ergotamine, had
the ability (amongst several others) to narrow only the blood vessels
around the brain. It was selective, with little effect on other blood
vessels.
In addition, it was already known that injections
of serotonin could relieve migraines. Perhaps methysergide was acting
on the same target proteins (receptors as they are known) in the blood
vessels involved in migraine as did serotonin. The hunt was on to find
these hitherto unknown receptors for serotonin. If they did, indeed,
exist, it might then be possible to develop better anti-migraine drugs
with fewer side-effects than the ergot-based compounds. These new drugs
would be based on serotonin, not ergot. Serotonin itself will never make
a good medicine, it plays too many roles in the body.
The researchers made thousands of serotonin look-alike molecules and
tried them to see if they would bind to the newly discovered targets.
One, known as sumatriptan, hit the target, which was a good start but
this alone did not mean it would have the desired effect on human migraine.
Other research was carried out to confirm that sumatriptan not only bound
to the new receptors but that it really did lead to constriction of brain
blood vessels without affecting circulation in other parts of the body.
 |
| This small molecule
has greatly improved the quality of life for many
people who suffer from migraine attacks. |
Preclinical studies
then established that sumatriptan was
safe
to be used in clinical trials Subsequent
clinical trials showed it was very effective
in treating
migraine, and sumatriptan was launched
as a specific treatment for acute migraine
in 1991.
It has since been joined by other triptan
drugs and life has been greatly improved
for many
migraine sufferers.
The development of triptans was a great
leap forward in migraine therapy. But not all
migraine sufferers respond to them. Also, even
though these treatments are pretty specific
for the brain blood vessels that cause migraine,
they cannot be safely used in people who have
heart disease or high blood pressure. The drugs
used to prevent migraine are also only moderately
effective. Thus, there is a need for further
research, to find more effective drugs for
treatment and prevention of migraine in all
sufferers.
To identify other brain areas involved in migraine that could provide additional drug targets, non-invasive imaging studies can be done of people while they are having a migraine.
For acute migraine therapy, BIBN 4096 BS, a molecule that blocks the activity of a neuropeptide called CGRP is looking very hopeful. Experiments have shown that CGRP is one of the chemical messengers released by the trigeminal nerve when it is stimulated that causes brain blood vessels to expand. Triptans work, at least in part, by preventing CGRP release from nerve endings but, triptans have some unwanted effects on blood vessels outside the brain, which can be dangerous for people with heart disease So if the effects of CGRP could be prevented in some other way, the result might be a migraine treatment with fewer side effects. BIBN 4096 BS blocks CGRP activity in the brain blood vessels of animals and has recently been successfully tested in migraine patients.
The study of migraine genetics is providing other potential leads for new treatments. There is a rare form of migraine (familial hemiplegic migraine) in which two genes are mutated. The proteins encoded by these genes are involved in the transmission of messages between nerves It is not known whether similar mutations are involved in the common forms of migraine but if they are, these proteins might be targets for new anti-migraine drugs.
For migraine prevention, there are also some hopeful leads, in particular the anti-epileptic drugs. Patients taking the new anti-epileptic topiramate noticed improvements in their headaches. Clinical trials have subsequently shown that topiramate reduces migraine frequency and it is now licensed for prevention of migraines. No additional animal experimentation was needed to extend topiramate's licence, because its safety had already been evaluated. Nevertheless, researchers are now trying to find out how topiramate achieves its effects . The results of these experiments might make it possible to design completely new drugs that will be even better at preventing migraine than topiramate.
 |
| Feverfew contains a molecule that may lead to a new treatment for migraine. |
Feverfew, an alternative remedy for migraine, is also being investigated as a preventive in clinical trials. Herbal potions can be problematic because they often contain several active compounds -some harmful and some beneficial - and the ratio of these varies from batch to batch. However, experiments in animals are beginning to provide clues about how parthenolide, the active constituent of feverfew, has its effects and at the same time they are revealing additional potential drug targets.
Finally, the toxin from a bacterium called Clostridium botulinum is attracting some attention as a possible way to prevent migraines. People receiving injections of "botox" for cosmetic facial surgery have reported a reduction of headaches and consequently clinical trials of botox injections have been started. However, the jury is still out on whether this approach will be useful in migraine or whether it is safe to use in this disorder.
|
|
This information has been generously supplied to the BioTrax Volunteer Support Group by the :
Coalition for Medical Progress
Medical research studies may be conducted and are carefully designed to answer specific medical questions while protecting participants´ safety. Well conducted medical trials are the fastest and safest way to find improved treatments and preventions for diseases. Clinical trials or interventional trials determine whether experimental preventions, treatments, or new ways of using known therapies are safe and effective under controlled conditions. Observational or natural history studies examine health issues and disease development in groups of people or populations. For more information on current medical trials or to register on the BioTrax database, view the study section at www.biotrax.com .
Why not E-Mail this Health Zone News Letter to a friend who may benefit or print copies to give to your support groups or friends ? Click on the buttons below .
