Drug is used to induce general anaesthesia but also provides powerful pain control for patients with painful conditions in lower doses.
Washington: Ketamine - a medication commonly used for pain relief and depression - may help alleviate migraine pain in patients who have not been helped by other treatments, a study has found.
The study of 61 patients found that almost 75 per cent experienced an improvement in their migraine intensity after a three- to seven-day course of inpatient treatment with ketamine.
The drug is used to induce general anaesthesia but also provides powerful pain control for patients with many painful conditions in lower doses than its anaesthetic use.
"Ketamine may hold promise as a treatment for migraine headaches in patients who have failed other treatments," said Eric Schwenk, director of orthopaedic anaesthesia at Thomas Jefferson University Hospital in the US.
"Our study focused only on short-term relief, but it is encouraging that this treatment might have the potential to help patients long-term. Our work provides the basis for future, prospective studies that involve larger numbers of patients," said Schwenk.
An estimated 12 per cent of the US population suffers from migraines - recurring attacks of throbbing or pulsing moderate to severe pain.
A subset of these patients, along with those who suffer from other types of headaches, do not respond to treatment.
During a migraine, people are often very sensitive to light, sound and may become nauseated or vomit. Migraines are three times more common in women than in men.
The researchers reviewed data for patients who received ketamine infusions for intractable migraine headaches - migraines that have failed all other therapies.
On a scale of 0-10, the average migraine headache pain rating at admission was 7.5, compared with 3.4 on discharge.
The average length of infusion was 5.1 days, and the day of lowest pain ratings was day 4. Adverse effects were generally mild, researchers said.
"Due to the retrospective nature of the study, we cannot definitively say that ketamine is entirely responsible for the pain relief, but we have provided a basis for additional larger studies to be undertaken," Schwenk said.