Drug Profiles:
Relpax® (eletriptan)

Introduction

During a migraine headache attack, brain activity changes induce inflammation of cerebral blood vessels and nerves. Attacks may be triggered by alcohol, certain foods, too much or too little sleep, menstruation, emotional stress, or environmental factors. Sumatriptan was the first serotonin agonist to be approved for treating migraine, but a new faster, more effective antimigraine drug is close to being approved for marketing: Relpax (eletriptan). Manufactured by Pfizer Inc., Relpax is also a serotonin agonist but its affinity for these receptors is different from that of sumatriptan.

How It Works

The triptan antimigraine drugs are derived from the serotonin molecule. They act on 5-hydroxytryptamine (HT) 1B/1D receptors on blood vessels, trigeminal neurons, and the trigeminal nucleus caudalis, causing constriction of extracerebral intracranial vessels, abolition of dural extravasation and neurogenic inflammation, and inhibition of trigeminal neuronal discharge. Relpax has more than a 6-fold higher affinity than sumatriptan at the 5-HT1D receptor and more than a 3-fold greater affinity at the 5-HT1B receptor. Relpax also binds potently to the 5-HT1F receptor.

PFIZER RECEIVES APPROVAL FOR ANTI-MIGRAINE MEDICINE RELPAX

NEW YORK, December 27 -- Pfizer Inc said today that it has received approval from the U.S. Food and Drug Administration to market Relpax (eletriptan hydrobromide) for the acute treatment of migraine.

Relpax is the newest product in the class of anti-migraine medicines known as triptans. In clinical trials involving more than 9,000 patients and more than 70,000 migraine attacks, Relpax was shown to relieve migraine pain and associated symptoms including nausea and sensitivity to light and sound. This relief can help patients return to their daily activities.

An estimated 28 million Americans—one in five women and one in 15 men—experience migraines. Most migraine sufferers are between the ages of 30 and 50, the most productive years of life. For many, migraine is a chronic and debilitating condition that affects the ability to function both at work and at home. Migraine costs American employers about $13 billion annually because of missed workdays and lost productivity due to impaired work function.

"With its effectiveness in treating pain and other symptoms of migraine, Relpax is an important new treatment option for patients that can help them get back to their lives," said Dr. Joseph Feczko, Pfizer's executive vice president of Global Research and Development and president of Worldwide Development.

Discovered and developed by Pfizer, Relpax is a selective 5-hydroxytryptamine 1B/1D (5-HT1B/1D) receptor agonist that acts at serotonin 5HT1B receptors on intracranial blood vessels and 5HT1D receptors on sensory nerve endings to relieve the pain and associated symptoms of a migraine attack.

Relpax was shown to be effective at doses of 20 mg, 40 mg and 80 mg. The maximum recommended single dose of Relpax is 40 mg.

The most common side effects reported in clinical trials included fatigue, somnolence, nausea, and dizziness. The common adverse events seen with Relpax are similar to adverse events reported with triptans as a class.

Relpax should not be used by patients with severe hepatic impairment, or those older than 65 years or younger than 18. Relpax tablets should not be used within at least 72 hours with potent CYP3A4 inhibitors.

Eletriptan (Relpax) has been approved for use in the acute treatment of migraine in 51 countries and has been introduced in 17 countries including Mexico, Italy, France and Japan.

Pfizer Neuroscience is committed to pioneering innovative therapies for neurological and psychiatric disorders. Pfizer's experience in the areas of depression, anxiety, schizophrenia, Alzheimer's disease and epilepsy has helped bring leading medicines to market for the treatment of these disorders.

Neurologic and psychiatric disorders represent an important priority in Pfizer's $5.2 billion development effort, with more than 20 percent of the research and development budget allocated to the development of more effective neuroscience medicines for disorders such as mood and anxiety disorders, migraine, neuropathic pain, fibromyalgia, epilepsy and smoking cessation.

Pfizer Inc discovers, develops, manufactures and markets leading prescription medicines, for humans and animals, and many of the world's best-known consumer products.
 

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