Lidocaine is an anesthetic agent, usually injected to produce numbness in a small area of skin. Lidocaine 4% aqueous solution can be applied intranasally for the treatment of headaches such as migraine and cluster headaches. It is available only by prescription. When it is used in cluster headaches, a pre-dosing spray of neo-synephrine 0.5% may be needed to alleviate some of the nasal congestion which may accompany cluster headaches.
There are several methods of application which have been used. The most effective method is to use long, cotton pledgetts inserted into the nostril for delivery of the medication. This technique is not well suited for self administration. For self administration, it is usually best applied as nasal drops. Some, however, recommend having the solution placed into a nasal spray device.
The supposed mechanism by which lidocaine works in clusters and migraines is by numbing the portion of the trigeminal nerve known as the sphenopalatine ganglion. The onset of pain relief is rapid and may occur within minutes after administration. The duration of the pain relief is brief, often recurring within the hour; however, this is not usually a problem for patients with cluster headaches since the attacks are often brief.
In migraines, where attacks can last a day or more, this can be problematic. Repeated dosing with lidocaine may produce not only side effects with periodic use but can lead to abnormalities of the heart rhythm and mental confusion due to toxic effects.
The most effective use of lidocaine is for the patient who has severe migraines and where the more specific abortive medications take an hour or more to produce resolution of the migraines. In these situations, it is administered intravenously.