Inhaled Oxygen Shown Effective for Cluster Headaches

Patient Expert

Cluster headaches are so painful that they've been called "suicide headaches." At this time, the only treatment that's FDA approved for the acute treatment of cluster headaches is subcutaneous sumatriptan (Imitrex injection).

For quite some time, cluster headache sufferers have been using inhaled oxygen and reporting that it often aborts a cluster headache. However, there has been little proof of this in medical literature, and getting a tank of oxygen has been difficult for many cluster sufferers. At times, this has been because their doctor didn't think it would work and didn't want to prescribe the oxygen. More frequently, however, it has been a matter of expense and insurance companies denying coverage.

Study results published in JAMA, the journal of the American Medical Association, have finally provided evidence that inhaled oxygen does work for some cluster headache sufferers.

Study Objective: "To ascertain whether high-flow inhaled oxygen was superior to placebo in the acute treatment of cluster headache."1


Study Methods:**

  • The study was double-blind, randomized, and placebo-controlled* trial

  • There were 109 adult participants, aged 18-70 years.

  • All participants were diagnosed with cluster headache as defined by the International Headache Society.

  • Participants treated four cluster headache episodes with high-flow inhaled oxygen or placebo (air in the tank), alternately.

  • Participants were randomized to the order in which they received the active treatment or placebo.

  • Participants were recruited and followed up between 2002 and 2007 at the National Hospital for Neurology and Neurosurgery in London, England.

  • High-flow oxygen at 100%, 12 L/min, or placebo was delivered by face mask, for 15 minutes at the start of an attack of cluster headache. This was done alternately for 4four attacks.

  • Participants could take rescue medications if they received no relief after 15 minutes of treatment.

Study Outcome Measures:

  • The primary endpoint of the study was for the participant to be pain free, or in the absence of a diary to have adequate relief, at 15 minutes.

  • Secondary endpoints measured included

    • Participant being pain-free at 30 minutes
    • reduction in pain up to 60 minutes
    • need for rescue medication 15 minutes after treatment
    • overall response to the treatment
    • overall functional disability
    • effect on associated symptoms

Study Results:

  • Of the original 109 participants, 57 with episodic cluster headache and 19 with chronic cluster headache were available for the analysis.

  • Pain-free at 15 minutes:

    • 78% of participants receiving high-flow oxygen
    • 20% of participants receiving air
  • There were no important adverse events.

Study Conclusion:

"Treatment of patients with cluster headache at symptom onset using inhaled high-flow oxygen compared with placebo was more likely to result in being pain-free at 15 minutes. Even though issues such as dosing and further studies of repeated attacks are warranted, the use of placebo in this patient group will be increasingly complex to use. This work paves the way for further studies to optimize the administration of oxygen and its more widespread use as an acute attack treatment in cluster headache, offering an evidence-based alternative to those who cannot take triptan agents."1

Summary and Comments:

Finally, we have documented evidence of the efficacy of inhaled oxygen for treating cluster headaches. To have a 78% success rate is indeed impressive, especially with so low a placebo rate. Placebo rate in clinical trials is frequently closer to 30%.

Obviously, the success rate is of utmost importance, but the lack of side effects is a huge plus for cluster headache sufferers. Many cluster sufferers have been using inhaled oxygen for quite some time, and many of them have been paying the expense out-of-pocket despite having insurance coverage. Hopefully, the strength of this study will help to change the practices of insurance companies.

For more information about cluster headaches, see Cluster Headaches - The Basics.

*** Clinical Trials Terminology:**3

  • double-blind: A clinical trial design in which neither the participating individuals nor the study staff knows which participants are receiving the experimental drug and which are receiving a placebo (or another therapy). Double-blind trials are thought to produce objective results, since the expectations of the doctor and the participant about the experimental drug do not affect the outcome; also called double-masked study.
  • randomized: A study in which participants are randomly (i.e., by chance) assigned to one of two or more treatment arms of a clinical trial. Occasionally placebos are utilized.
  • placebo-controlled: A method of investigation of drugs in which an inactive substance (the placebo) is given to one group of participants, while the drug being tested is given to another group. The results obtained in the two groups are then compared to see if the investigational treatment is more effective in treating the condition.
  • endpoint: Overall outcome that the protocol is designed to evaluate. Common endpoints are severe toxicity, disease progression, or death.


1 Cohen, Anna S., PhD, MRCP; Burns, Brian, MD, MRCP; Goadsby, Peter J. MD, PhD, DSc, FRACP, FRCP. "Hight-Flow Oxygen for Treatment of Cluster Headache." JAMA, December 9, 2009--Vol 302, No. 22.

2 Cox, Lauren. "Oxygen Therapy Can Help Cluster Headaches." ABC News. December 9, 2009.

3 "Glossary of Clinical Trial Terms."

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