Migraine Headache

Migraine pain has been called indescribable, yet 35 million Americans know it all too well. Migraine is the French derivation of the Greek word hemikrania, meaning “half a head,” referring to the typical pattern of migraine distress — pain only on one side of the head, most often at the temple (see Figure 5). The affected side can vary from one attack to the next or during a single episode.

Figure 5: Migraine Headache Pain   Migraine headache pain   Unlike tension and sinus headaches, which produce a dull, steady pain, the pain of migraine headache is throbbing or sharp. It usually occurs on one side of the head only, confined to the temple, eye, or back of the head.

The pain ranges from moderate to severe. Unlike tension headache, migraine headache can keep you from sleeping or rouse you from sound slumber. Most people describe the pain as pulsating or throbbing. It can also be sharp, almost as if a dagger is piercing your temple or eye.

Nausea and vomiting are common during a migraine headache. Likewise, tense head, neck, and shoulder muscles can accompany a migraine headache. In most cases, this is thought to be an involuntary response to the pain, rather than its cause (although tight muscles can trigger a migraine headache). Bright lights and loud noises worsen the pain and may push someone with a migraine headache to seek out quiet, dimly lit places. Similarly, smell may aggravate nausea and cause vomiting.

Anatomy of an Attack

To most people, “migraine” means a particular type of head pain. Actually, the term refers to a broader set of changes that may occur throughout the body, although not all of these symptoms are evident in every person who has migraine. Typically these early sensations might include a change in mood, appetite, or activity level. These symptoms, known as prodromal symptoms or the prodrome, warn that a migraine headache is on the way.

Some people also experience visual disturbances shortly before the headache begins. These might include seeing sparkling or flashing zigzag lines (scintillations) or white spots (scotoma). Less often, people will experience tingling on one side of the body, often in the hand, arm, and face. Such visual and sensory disturbances generally last anywhere from 10–30 minutes and are known as the aura. The presence or absence of aura determines whether an episode is a classic migraine (with aura) or common migraine (without aura). (For information on headaches that have some similarities to migraine, see “Migraine relatives.”)

What causes a migraine headache and — when it occurs — an aura? Experts aren’t sure. Two competing theories exist. For many years, scientists believed that a tightening of the cerebral arteries interfered with blood flow. The arteries would then dilate to compensate, not only in the brain but also outside in the skull, where the dilation causes inflammation. Although scientists still believe that this combination of blood vessel dilation and inflammation causes migraine headache, they no longer think that it underlies the aura.

Here’s why: Although researchers have confirmed that the aura coincides with a reduction in blood flow, this reduction isn’t consistent with vessel constriction or spasm because these conditions would have a more substantial effect. Instead, many experts now suspect that aura is produced by a neurological phenomenon known as spreading depression, which is a wave of decreased electrical activity (indicating lower brain cell functioning) and diminished blood flow that inexplicably washes across the cerebral cortex (see Figure 6). Bolstering this theory is the fact that a resting brain is more susceptible to spreading depression than an active one, which may explain why migraine attacks often strike as people unwind after a stressful period.

A migraine attack can also consist of an aura only, with no headache. This type of migraine is more common in older people and is sometimes confused with a transient ischemic attack (TIA), also called a “mini-stroke,” which often is the first sign of an impending stroke. TIAs occur when a blood clot temporarily interrupts blood flow through one of the smaller arteries in the brain. Symptoms may include weakness on one side of the body or blindness in one eye. If you’ve suffered from migraine throughout your life, remember these similarities, because you may be able to avoid expensive and sometimes risky tests for TIAs. But if in doubt, err on the side of caution.

Figure 6: How the aura may occur   How the aura may occur   A phenomenon known as cortical spreading depression is probably responsible for the aura that sometimes precedes migraine headache. This occurs when neuronal activity initially increases and then rapidly decreases in portions of the brain. As neuronal communication is suppressed, cerebral blood flow diminishes. The areas of lowered activity gradually spread, as if washing across the brain, causing symptoms of aura. Altered cerebral blood flow and electrical activity occur first in the primary visual cortex, which may help explain why visual disturbances often accompany the aura. Symptoms affecting the extremities, such as numbness and tingling, may occur when the spreading depression reaches the primary sensorimotor cortex. The spreading depression usually stops about halfway across the brain. At that point, a parallel process, involving a combination of vasodilation and inflammation, may be causing headache pain.

Timing of Attacks

Many migraine attacks occur in the evening or at night and, ironically, may be the result of the body’s attempt to relax after the day’s stresses. Blood vessels tighten in response to stress and widen during relaxation, and dilated blood vessels in the head are a chief trigger for migraine pain. What’s more, relaxation lowers an individual’s pain threshold. Thus, an evening or nighttime migraine usually occurs after a particularly intense day or a period of prolonged stress.

Both the frequency and the duration of migraine headaches vary from person to person. Migraine headaches usually last at least 6 hours, and usually no longer than 24 hours. On occasion, however, they can persist for days, especially in women who have these headaches before or during menstruation.

Who’s at Risk?

During childhood, migraine affects boys and girls equally. But after puberty, the situation shifts, with women more likely to experience migraine headaches. About 9% of men and 16% of women suffer from migraine. The tendency for migraine runs in families. There also seems to be a connection with motion sickness: Many adult migraine sufferers recall bouts of carsickness as children.

Estrogen has long been linked to headaches. Women are more likely to experience migraine and other kinds of headaches during menstruation and, to a lesser extent, ovulation. Migraine headaches that occur in the days before menstruation tend to be particularly severe and incapacitating.

Menstrual migraine headache can be treated like any other migraine headache. For milder cases, try aspirin or an NSAID, such as ibuprofen, daily during the week of your period. Birth control pills may increase the frequency or intensity of attacks, although low-estrogen birth control pills may prevent menstrual migraine headaches in some cases. At menopause, menstrual migraine headaches should improve as long as you don’t take hormone therapy — which may actually increase the frequency and intensity of the attacks.

Migraine Triggers

Many factors that cause tension headache — such as stress, lack of sleep, or missing a meal — can also trigger migraine headaches. But for some migraine sufferers, alcohol or a particular food may prompt an attack (see “Migraine menu”). The list is long, but foods known to cause migraine headaches include chocolate and aged cheeses, as well as additives like nitrates, found in most cured meats, and monosodium glutamate (MSG), an ingredient in some canned, processed, and Chinese foods. Of course, if you can identify such a trigger, your prevention strategy is simple: Avoid it.

Most people have dozens of triggers, and it’s often impossible to avoid all of them. What’s more, the effect of a given trigger on your headache can be unpredictable. And triggers often interact. For example, stress may not cause an attack without fatigue. In such a case, you may be able to use your list of triggers to manage a headache, if not prevent it. If a woman knows she’s more vulnerable to migraine during menstruation, she may want to avoid alcohol during this time. Migraine headaches are also most common on weekends, perhaps because people are more likely to drink alcohol, postpone sleep, or experience caffeine withdrawal (some people drink less coffee on weekends or have their first cup later than usual). When migraine headaches are frequent, they can cause muscle tightness, which can, in turn, trigger more headaches.

How does a trigger spur a migraine headache? Experts don’t know for sure whether it first causes dilation or inflammation of blood vessels. There are staunch partisans of both views. Indeed, different triggers may work through different mechanisms. The two processes also seem interconnected, and their interaction may foster a migraine headache once it’s started. For instance, widening of a blood vessel causes inflammation, and inflammation causes a vessel to expand. To further complicate matters, researchers believe that different triggers affect this relationship in different ways.

Treating Migraine Headache

When migraine headaches are not particularly intense, you may want to try some home remedies before seeing a doctor. For some folks, strong, caffeinated black coffee is a simple and safe solution. Caffeine acts as a vasoconstrictor, meaning it causes blood vessels to narrow (see Figure 7). A migraine headache may also respond to an OTC analgesic (see “Over-the-counter medications”), if it’s taken when the pain is still mild. The prescription medication isometheptene (Midrin), which is a mild vasoconstrictor, may also be helpful. Even then, this treatment is likely to only lessen, not eliminate, the pain.

Figure 7: Caffeine as a home remedy   Caffeine as a home remedy   Some people find that simply drinking a caffeinated beverage can ease their migraine headache. This is because caffeine causes blood vessels to narrow and the pain of a migraine headache is caused by the expansion of blood vessels. Therefore, caffeine offers relief by counteracting the vasodilation.

Most people with migraine headaches turn to their doctors for prescription medications, and the sooner the better. A crucial principle in treating migraine headache is that it’s much easier to nip it in the bud than to end an entrenched attack. It takes a quick-acting medication to squelch migraine pain. Most physicians start by prescribing a class of drugs called selective serotonin agonists, or triptans. If this initial strategy doesn’t work, other options are available.

Triptans

These medications offer most migraine sufferers significant relief with relatively few side effects (see Table 4). Triptans work by constricting blood vessels in the head and possibly by inhibiting inflammation.

In pill form, almotriptan (Axert), eletriptan (Relpax), rizatriptan (Maxalt), sumatriptan (Imitrex), or zolmitriptan (Zomig) can stop the headache within two hours, provided the drug is taken when the headache is still mild. Although naratriptan (Amerge) and frovatriptan (Frova) can take nearly twice as long to work, they have fewer side effects and are more effective in preventing the headache’s return within 24 hours. Sumatriptan and zolmitriptan come in nasal sprays that cut the medication’s absorption time to an hour, making them a good choice for more intense migraine headaches. An injectable form of sumatriptan can provide relief in as little as 15 minutes. It’s available in an automatic injector, allowing individuals to self-administer the drug, although many are hesitant to do so. The injections also tend to cause muscle tightness, which can worsen the headache or cause chest pressure.

If one triptan doesn’t work, another often will (although you may have to wait 24 hours before taking a different type). If your headache still isn’t completely relieved, taking aspirin or an NSAID — such as ibuprofen, naproxen sodium, or ketoprofen (see “Over-the-counter medications”) — along with the triptan may help.

When taking triptans, you may experience some mild side effects. The oral medications can cause a tingling in your fingers or tightness in your throat, while the nasal spray can leave a bad taste in your mouth. The injectable form of sumatriptan tends to cause more intense side effects. On the other hand, triptans don’t cause the nausea and vomiting common to the ergots, an older class of migraine medications.

The triptans are expensive, and 30%–40% of the time, the headache returns within 24 hours. Depending on the dose, you may be able to take the same triptan again during a given 24-hour period, but you can’t take a different form of triptan or a similarly working ergot. Because triptans and ergots narrow blood vessels, taking them at the same time could lead to a heart attack. Not surprisingly, people with heart disease or uncontrolled high blood pressure shouldn’t take these medications at all.

Ergots

Ergots, originally derived from a rye fungus, can be useful in treating migraine headache (see Table 5). Ergots, which have been available by prescription since the 1920s, constrict blood vessels. The triptans affect blood vessels only in the head, but the ergots affect blood vessels throughout the body, which means that they carry more risks. They also cause more side effects and take longer to work than triptans. However, the beneficial effects of ergots last longer, so that you will be less likely to suffer a headache recurrence.

Nasal dihydroergotamine (Migranal) is most effective when taken at the first hint of a migraine headache. Ergotamine suppository (Cafergot) or injectable dihydroergotamine (DHE 45) may be useful for severe headaches because they’re absorbed faster than ergots in traditional pill form. However, one thing to keep in mind is that ergotamine suppository, the most widely prescribed agent, tends to cause nausea and vomiting. Apart from being unpleasant, an upset stomach hinders the absorption of medications.

Something else to consider: If it’s used as infrequently as once a week, ergotamine can increase the frequency of migraine headaches by causing rebound headaches. To help prevent rebound headaches, carefully follow your physician’s instructions. This will also help protect you from serious side effects, including gangrene, which is rare but can result from large overdoses of the drug.

Dihydroergotamine is less likely than ergotamine to lead to nausea and vomiting. It used to be available only by injection, which made it a less popular alternative to ergotamine. Now it’s available as a nasal spray. The spray, however, tends to be less effective than the injection or the ergotamine suppositories.

Prescription Analgesics

Prescription painkillers are more powerful than their OTC equivalents, yet they rarely relieve severe migraine pain. In many cases, prescription analgesics just provide higher doses of standard nonprescription products, such as ibuprofen or naproxen sodium. Some prescription analgesics contain barbiturates or opioids. Opioids, such as codeine and morphine, are sometimes indispensable medications, but they have a limited role in the treatment of headache. People who use opioids regularly run the risk of developing a tolerance to them and becoming addicted. This means they need higher and higher doses to relieve the pain, and they develop withdrawal symptoms when they stop taking the medication.

Other Drugs

Occasionally, a migraine headache is exceptionally stubborn: Despite treatment, it may persist for days or weeks. When this happens, a several-day course of a steroid, such as prednisone, may provide relief.

Migraine attacks often activate the sympathetic nervous system, which is probably best known for its role in the “fight or flight” response. Activating the sympathetic nervous system affects the stomach and intestines, as well as other parts of the body. As a result, nausea and vomiting often accompany migraine headaches, which prevent you from keeping down your medications. Even when vomiting does not occur, the stomach takes longer to empty into the intestines once the sympathetic nervous system is activated — which can impair the absorption of oral medications.

To prevent vomiting, your doctor may recommend that you take a prescription antinausea medication. Several options exist. The phenothiazines suppress nausea and — because they have sedative effects — also help you sleep. The antinausea medication metoclopramide (Reglan) helps empty the stomach, thereby improving the absorption of oral headache medications. Many people find it particularly effective to take metoclopramide at the first hint of a migraine headache and then, about 15 minutes later, take the first dose of headache medication. Virtually all the antinausea drugs are available in several forms. If you can’t take them by mouth, you can try rectal suppositories and, in extreme cases, injections.

Preventing Migraine Headache

When migraine headache attacks are particularly severe, do not respond to treatment, or occur more than three to four times a month, it’s wise to investigate preventive strategies. Generally, preventive therapy involves taking a course of medication daily, gradually tapering the dose, and, ideally, eventually discontinuing it altogether.

Beta blockers, used to treat high blood pressure and angina, and tricyclic antidepressants can reduce the frequency of migraine headaches by 50%–60%. They can also reduce the intensity and duration of the headaches. Calcium-channel blockers, also used to treat high blood pressure and angina, don’t have the track record of the beta blockers, but they show promise. Anticonvulsant medications may also help (see Table 6).

Beta Blockers

Doctors have prescribed these medications for years to treat high blood pressure, abnormal heart rhythms, and angina. Beta blockers may relieve migraine headaches by hampering blood vessel expansion.

Six beta blockers have been found effective in preventing migraine headaches (see Table 6). The most effective medication varies from person to person, so if the first one doesn’t work, it’s worth trying another.

Side effects can include fatigue, dizziness, cold hands and feet, exercise intolerance, insomnia, shortness of breath, depression, and impotence. People with respiratory problems, including asthma and other chronic lung disorders, should not use beta blockers. In some people, they also worsen congestive heart failure.

Tricyclic Antidepressants

These medications are prescribed to treat various types of pain, including headache. Amitriptyline (Elavil, Endep) is the best studied for pain relief and the most often prescribed for migraine prevention: It’s about 60% effective in thwarting such headaches. Other tricyclics used in migraine prevention include desipramine (Norpramin), imipramine (Norfranil, Tipramine, Tofranil), and nortriptyline (Aventyl, Pamelor). It is not clear how the tricyclics work, but it is possible that they relieve pain by increasing the availability of the neurotransmitters serotonin and norepinephrine, which not only affect mood but also act to reduce pain signals.

When taking a tricyclic, you probably won’t notice any benefit in the first week or two, and you may not feel its full effects for several weeks. However, some sedative effects are common early in treatment, which is a bonus for the many people with migraine who also have difficulty sleeping. Although a tricyclic could potentially improve mood, the doses prescribed for headache prevention are much lower than those used in treating depression. Side effects can include dry mouth, blurred vision, dizziness, constipation, and difficulty urinating. Tricyclics can also cause weight gain and heart rhythm disturbances, so people with heart disease should probably avoid them.

Calcium-Channel Blockers

Like beta blockers, calcium-channel blockers are often prescribed for people with high blood pressure or heart disease, as well as for migraine prevention. But these medications work in different ways. Calcium-channel blockers relax muscle cells in blood vessel walls and prevent blood vessel spasm, which is what first prompted scientists to investigate their value for migraine prevention. As it turns out, however, calcium-channel blockers are effective at preventing migraine not so much because they increase blood circulation, but because they act directly on brain cells and thwart inflammation.

Treatment usually begins with a low dose that’s increased gradually. Despite their name, calcium-channel blockers don’t interfere with the absorption of calcium, nor do they cause calcium loss in the bones. Instead, they prevent the transmission of electrical signals — including pain signals — in the brain by blocking the calcium ion channels that must open before such signals pass from one cell to another. Side effects include fatigue, dizziness, constipation, and swelling of the feet. Calcium-channel blockers may not be the best choice for people with congestive heart failure or heart rhythm abnormalities.

Anticonvulsants

The anticonvulsant, or antiseizure, medications topiramate (Topamax) and divalproex (Depakote) are among the few medications specifically approved for migraine prevention. Another anticonvulsant used for migraine prevention is gabapentin (Neurontin), even though it is not specifically FDA-approved for this use. Although the mechanisms are not entirely clear, anticonvulsants appear to work by reducing the transmission of pain signals in the brain.

Divalproex effectively prevents migraine headaches for about half of those who use it. However, beta blockers and tricyclics are generally more effective and better tolerated. Divalproex tends to be about as effective as calcium-channel blockers, although it’s not as well tolerated. Its side effects can include nausea, diarrhea, weakness, weight gain, and tremor. Very rarely, it can cause potentially fatal liver failure. Consequently, people with liver disease shouldn’t take this medication. Nor is it recommended for women who are pregnant or trying to become pregnant. Anyone who takes divalproex should have regular liver function tests.

Topiramate and gabapentin don’t impair liver function, but these medications have other side effects to consider (see Table 6). One risk to keep in mind: Topiramate may encourage the formation of kidney stones, so people taking it should drink plenty of fluids. Even so, topiramate and gabapentin offer an alternative for people who do not respond to divalproex. Studies conducted to obtain FDA approval showed that topiramate reduces the frequency of migraine headaches, and at least one study found that these effects last at least six months. Gabapentin has also been studied in randomized placebo-controlled studies.

Other Drugs

The Physicians’ Health Study has presented evidence that aspirin can provide short-term migraine prevention. The study, which involved 22,000 male physicians, primarily evaluated the effectiveness of low-dose aspirin in reducing risk of heart attack, but it also compared the rate of migraine headaches. The researchers found that men who took aspirin experienced roughly 20% fewer migraine headaches during the study than did those receiving a placebo.

Although low-dose aspirin was considerably less effective than the standard migraine headache preventive medications, it may be that it can improve migraine control when used in combination with a preventive medication. Further research is needed to confirm this hypothesis. It’s also important to keep in mind that aspirin has some potential risks, such as irritation of the stomach lining and internal bleeding, which can lead to anemia.

In addition, although investigators had hoped that small doses of botulinum toxin might prevent migraine headache, a number of clinical trials have now shown that this approach is not effective (see “The latest on botulinum toxin,” below).