Pilot Study Evaluating the Use of Nasal Carbon Dioxide for the Treatment of Cluster Headache

Inclusion Criteria: * Male and female, 18 years of age and older. * History of episodic cluster headache, as defined by International Classification of Headache Disorders (ICHD), third edition, beta version guidelines (ICHD-3 beta, Cephalalgia 2013). * History of cluster headache attack-free remission periods lasting \> 1 month within the previous year. * Stable on medications, including those for the treatment of cluster headache prevention/prophylaxis, for at least 60 days prior to baseline (including, but not limited to, verapamil, lithium, melatonin, any anticonvulsant, any systemic corticosteroid or steroid injection, occipital nerve block, other cranial or extracranial nerve block, or any neurostimulation treatment). Note: Subjects are allowed to use their usual standard of care for the acute/abortive treatment of acute cluster attacks 60 or more minutes after the initial dose, limited to the following: triptans; high-flow oxygen. * If female and of childbearing potential, have a negative urine pregnancy test at the time of Screening. a. To not be considered childbearing potential a subject must be surgically sterile, have had a hysterectomy or tubal ligation, post-menopausal for at least 1 year, or otherwise incapable of pregnancy. * Capable of completing online headache diary with access to internet. * Able to provide written Informed Consent. Exclusion Criteria: * Recent nasal/midface trauma (\< 3 months) * Recent nasal/sinus surgery (\< 3 months). * Severe respiratory distress in the last 6 months. * Neoplasm such as Angiofibroma, sinus tumor, granuloma. * Nasal congestion present more than 10 days with fever (temperature ≥ 100.4 °F) and nasal mucous is an abnormal color. * Surgery to treat cluster headache. * History of aneurysm, intracranial hemorrhage, brain tumors or significant head trauma. * Structural intracranial or cervical vascular lesions that may potentially cause headache attacks. * Other significant pain problems (including cancer pain, fibromyalgia, and trigeminal neuralgia) that might confound the study assessments in the investigator opinion. * Psychiatric disorder, which in the opinion of the Investigator, may interfere with the study. * Pregnant, actively trying to become pregnant, or breastfeeding, and/or is unwilling to use an accepted form of birth control. * Skin around and inside the nasal passage that is dry, cracked, oozing, or bleeding. * Recurrent nose bleeds, which in the opinion of the Investigator, may interfere with the study. * Is participating in any other therapeutic clinical investigation or has participated in a clinical trial and received treatment in the preceding 30 days.