FDA Approves Nasal Spray Version of Imitrex to Treat Migraines

WASHINGTON — The U.S. Food and Drug Administration has approved a new nasal spray for treating migraines, maker Glaxo Wellcome said Friday.

London-based Glaxo said it would start marketing the spray version of Imitrex in October.

Imitrex, also known as Imigran, is the first of a new class of drugs known as triptans. Imigran chalked up sales of $500 million in the first half of 1996.

Imitrex is estimated to hold more than 70% of the $1.1-billion migraine drug market, but several companies are racing to get their versions of triptans onto the market.

Glaxo rival Zeneca Group, which makes another drug in the same class known as zolmitriptan, says it expects the worldwide migraine market to reach $2.4 million by 2000.

The new triptan drugs are based on the neurotransmitter, or message-carrying chemical, serotonin. They home in on cell receptors known as 5HT-1--chemical doorways that serotonin uses to enter the cells and do its work.

“The way it works is during a migraine the blood vessels in the head become swollen and leaky, and what Imitrex does is restore them to their normal size, which relieves the pain,” said Ramona Jones, a spokeswoman for Glaxo’s U.S. subsidiary in Research Triangle Park, N.C.

The drug is already available in pill form and home-injection kits, but Jones said the nasal spray is quicker and easier to use.

“It goes into the nose and it is absorbed and gets to the vessels in the brain,” she said. After the injection, which offers relief from the debilitating pain of a migraine in 10 minutes, the spray is the quickest method of delivery.

Pills were not always appropriate, either.

“Migraine is sometimes accompanied by nausea and vomiting, so sometimes a tablet is not always the best route of administration,” Jones said.

The drug is available only by prescription and must not be used by people with certain kinds of heart disease, including uncontrolled high blood pressure. People using the older class of drugs known as ergotamines must also not use it.

Migraine is the world’s most common neurological disease, affecting 585 million people.