Migraine
Migraine Highlights
Migraines are very prevalent and affect more than 30 million Americans. Migraine headache is characterized by a throbbing pain of mild to severe intensity that typically lasts between 4 and 72 hours. In addition, migraine headache is commonly accompanied by other symptoms such as nausea, vomiting, and sensitivity to light (photophobia) and sound (phonophobia.)
Migraine is very prevalent. The 2005 American Migraine Prevalence and Prevention (AMPP) study, sponsored by the National Headache Foundation, estimated that there are approximately 30 million people who suffer from migraines in the United States, with fewer than half that number seeking treatment. Approximately 25% of migraine sufferers, frequently referred to as migraineurs, endure at least one attack per week. In terms of severity, approximately 75% of migraineurs report mild to moderate headaches with the remaining 25% classified as severe. Since 1992 when Imitrex®, the first triptan and market leader, was introduced, a number of new products have entered the $2 billion U.S. market for prescription medicines for migraine. However, there has been no drug with a new mechanism of action introduced in the migraine market in over a decade. The AMPP study also confirmed that, despite the number of drugs available to treat migraines, large numbers of migraine sufferers are not getting adequate treatment or the relief they need.
Current Treatments
Despite being such a common disorder, the biological cause of migraine is not completely understood. The treatment used by migraineurs depends on the frequency, duration and severity of the attacks. If the patient suffers from a mild migraine, or is initially unaware that their headache is a migraine, they generally treat themselves with an over-the-counter analgesic such as aspirin or ibuprofen. For patients that experience more moderate or severe pain, over-the-counter medications have limited effectiveness and they are treated with a prescription medication. To date, all prescription medications for migraine act by constricting blood vessels in the brain. One such class of prescription medications is the triptans.
Triptans are the most commonly prescribed drugs for the treatment of moderate to severe migraine. There are seven triptans approved for use and Imitrex®, marketed by GlaxoSmithKline, dominates the market. Other triptans are: Zomig®, Maxalt®, Amerge®, Frova™, Axert®, and Relpax®. Patients who suffer from a mild migraine, or are unaware that their headache is a migraine, generally treat themselves with an over-the-counter analgesic such as aspirin or ibuprofen. Patients who present to emergency rooms are treated with triptans and other potent drugs, such as ergotamine tartrate derivatives and opioids. While triptans are the gold standard therapy for stopping a migraine attack, they are effective in only 60-65% of patients and should not be prescribed to patients with hypertension or cardiovascular disease. While not specifically approved for migraine, opioid analgesics are effective but are known to have troublesome side effects including constipation, nausea, dizziness, sedation, respiratory depression, urinary retention and addictive properties.