Background
Chronic cluster headache (CH) is a rare, highly disabling primary headache condition. As NMDA receptors are possibly overactive in CH, NMDA receptor antagonists, such as ketamine, could be of interest in patients with intractable CH.
Case reports
Two Caucasian males, 28 and 45 years-old, with chronic intractable CH, received a single ketamine infusion (0.5 mg/kg over 2 h) combined with magnesium sulfate (3000 mg over 30 min) in an outpatient setting. This treatment led to a complete relief from symptoms (attack frequency and pain intensity) for one patient and partial relief (50%) for the other patient, for 6 weeks in both cases.
Conclusion
The NMDA receptor is a potential target for the treatment of chronic CH. Randomized, placebo-controlled studies are warranted to establish both safety and efficacy of such treatment.