New York, Oct 23 (IANS): Researchers have found that Ketamine -- a medication commonly used for pain relief and increasingly used for depression -- may help alleviate migraine pain in patients who have not been helped by other treatments.

"Ketamine may hold promise as a treatment for migraine headaches in patients who have failed other treatments," said Eric Schwenk, director of orthopaedic anesthesia at Thomas Jefferson University Hospital in Philadelphia.

"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," Schwenk said.

The study being presented at the ANESTHESIOLOGY 2017 annual meeting found that almost 75 per cent of the patients 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 anesthesia but also provides powerful pain control for patients with many painful conditions in lower doses than its anesthetic use.

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.

The researcher said while his hospital uses ketamine to treat intractable migraines, the treatment is not yet widely available.

"We hope to expand its use to both more patients and more conditions in the future," Schwenk 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 added.