Millions of people who suffer from severe migraines could be helped with ketamine, a new study suggests.
The horse tranquiliser, used illegally as a party drug, may be an effective treatment for those who fail to respond to other medications.
Ketamine made the debilitating headaches less painful for nearly three quarters, the researchers at Thomas Jefferson University Hospital, Philadelphia, found.
It offers hope of an effective remedy, with many desperate sufferers using alternative treatments as a last resort for their pain, including acupuncture and lavender oil.
The horse tranquiliser, used illegally as a party drug, may be an effective treatment for those who fail to respond to other medications
Lead author Dr Eric Schwenk said: ‘Ketamine may hold promise as a treatment for migraine headaches in patients who have failed other treatments.
‘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.’
Migraine is the third most common disease in the world, according to estimates. It affects around 37 million in the US and six million in the UK.
How was the study carried out?
The study, presented at the ANESTHESIOLOGY annual meeting in Boston, revolved around 61 male migraine sufferers.
The patients, who were all in their 40s and had been admitted to hospital, suffered intractable migraines – which have beaten all other therapies.
Researchers found their pain rating, recorded on a scale of zero to 10, had more than halved, in patients given ketamine during their hospital stay.
They were treated with regular infusions of ketamine after being fitted up with a drip for either three or seven days.
What did they find?
When they were admitted, their migraine pain was 7.5 on average. This dropped to 3.4 by the time they were discharged.
The average length of infusion was 5.1 days, with the fourth day recording the lowest pain ratings.
Adverse effects, which included hallucinations and vivid dreams among some of the patients, were generally mild.
Dr Schwenk said while his hospital uses ketamine to treat intractable migraines, it is not yet widely available.
Thomas Jefferson University Hospital will be opening a new infusion centre this autumn that will treat more patients with headaches using ketamine.
Migraines: The facts
The World Health Organisation recognises migraine as one of the most disabling lifetime conditions, yet awareness and understanding is low.
Some patients do not respond to regular painkillers such as aspirin or ibuprofen for the recurring attacks of throbbing or pulsing moderate to severe pain.
During a migraine, people are often very sensitive to light, sound and may become nauseated or vomit. Attacks can last for more than a day.
They are often preceded by visual disturbances such as flashing lights, shimmering lines and blind spots, caused by a wave of electrical activity in brain cells.
Stress is strongly connected. Other possible causes are caffeine, dehydration, skipping meals or eating high sugary foods. A genetic link is also suspected.