Levetiracetam is a unique molecule used for control of seizures and has also been shown to be useful for refractory headaches and refractory neuropathic pain, both orally and intravenously. We currently describe treatment of an acute or ongoing flareup of cluster headache with IV levetiracetam in a clinic setting. 5 case reports are described at this point. All were males who had onset of or ongoing cluster headaches. 1 patient had co-existent migraines. They came to the headache clinic; an IV was placed and levetiracetam was given IV. A 400–800mg test dose was given. Then, 800–1200 mg was given IV every 10 minutes with pulse oximetry monitoring. Patients rated their cluster severity on a 0–10 numeric rating scale (NRS), at the clinic and for the next few days after treatment. No other medications were given. All 5 patients reported cessation of cluster headache fattacks with treatment in the clinic. No other patients were treated in which IV levetiracetam did not have any effect. All treated patients were placed on oral levetiracetam for prophylaxis of cluster headaches. Average dose intravenously in the clinic was 7280mg over 45–60 minutes. Side effects were not reported other than transient drowsiness in 1 patient. IV levetiracetam is a powerful potential option for treating acute cluster headaches, in the setting of a headache clinic. This is typically a very difficult headache to treat acutely. Safety, tolerability and, most importantly, efficacy have been well demonstrated in this small open-label study treating ongoing cluster headaches. Double-blind studies are warranted for levetiracetam IV treatment to replicate these initial findings.