NEW YORK, Apr 21 (Reuters Health) -- Injections of botulinum toxin ('Botox') into cranial muscles appear to relieve the pain of tension headache, researchers report.
Headaches "are less frequent and less intense" following Botox therapy, said study co-author Dr. Maja Relja of the University of Zagreb in Zagreb, Croatia. She presented the findings at the annual meeting of the American Academy of Neurology (AAN), held this week in Toronto, Canada.
The exact causes of tension headaches remain unclear, although most are thought to be linked to stress. In most -- but not all -- cases, patients are able to gain relief through the use of over-the-counter pain relievers.
In an AAN statement, Relja explained that "since muscular contraction could be one explanation for the pain in patients with tension-type headache, I started to treat these patients with botulinum toxin." Botox is a temporary muscle paralyzer, used to treat conditions ranging from Parkinson's disease to facial wrinkles.
Relja and co-author Dr. Marta Korsic treated 16 patients suffering from recurrent tension headache with either Botox injections into the cranial muscle, or a 'dummy' placebo for 8 weeks. Each patient was asked to keep a headache 'diary' during the study.
"According to patient's diaries, the severity and the duration of the attacks decreased significantly during the treatment period," the researchers report.
Patients reported some "local pain at injection" associated with treatment.
Relja believes "this is the first double-blind study that suggests that botulinum toxin is a safe, effective treatment for people with tension-type headache." The success of the therapy also appears to support the theory of muscle tension as a cause of tension headache.
The study was funded by Allergan, Inc., manufacturers of botulinum toxin.
