Literature Review

International survey probes oxygen’s efficacy for cluster headache



Oxygen is a highly effective treatment for cluster headache with few complications, according to patient survey results published in the February issue of Headache. According to the results, triptans also are highly effective, with some side effects. Newer medications deserve further study, the researchers said.

To assess the effectiveness and adverse effects of acute cluster headache medications in a large international sample, Stuart M. Pearson, a researcher in the department of psychology at the University of West Georgia in Carrollton, and his coauthors analyzed data from the Cluster Headache Questionnaire. Respondents from more than 50 countries completed the online survey; most were from the United States, the United Kingdom, and Canada. The survey included questions about cluster headache diagnostic criteria and medication effectiveness, complications, and access to medications.

In all, 3,251 subjects participated in the questionnaire, and 2,193 respondents met criteria for the study; 1,604 had cluster headache, and 589 had probable cluster headache. Among the respondents with cluster headache, 68.8% were male, 78.0% had episodic cluster headache, and the average age was 46 years. More than half of respondents reported complete or very effective treatment for triptans (54%) and oxygen (also 54%). The proportion of respondents who reported that ergot derivatives, caffeine or energy drinks, and intranasal ketamine were completely or very effective ranged from 14% to 25%. Patients were less likely to report high levels of efficacy for opioids (6%), intranasal capsaicin (5%), and intranasal lidocaine (2%).

Participants experienced few complications from oxygen, with 99% reporting no or minimal physical and medical complications, and 97% reporting no or minimal psychological and emotional complications. Patients also reported few complications from intranasal lidocaine, intranasal ketamine, intranasal capsaicin, and caffeine and energy drinks. For triptans, 74% of respondents reported no or minimal physical and medical complications, and 85% reported no or minimal psychological and emotional complications.

Among the 139 participants with cluster headache who were aged 65 years or older, responses were similar to those for the entire population. In addition, the 589 respondents with probable cluster headache reported similar efficacy data, compared with respondents with a full diagnosis of cluster headache.

“Oxygen in particular had a high rate of complete effectiveness, a low rate of ineffectiveness, and a low rate of physical, medical, emotional, and psychological side effects,” the investigators said. “However, respondents reported that it was difficult to obtain.”

Limited insurance coverage of oxygen may affect access, even though the treatment has a Level A recommendation for the acute treatment of cluster headache in the American Headache Society guidelines, the authors said. Physicians also may pose a barrier. A prior study found that 12% of providers did not prescribe oxygen for cluster headache because they doubted its efficacy or did not know about it. In addition, there may be concerns that the treatment could be a fire hazard in a patient population that has high rates of smoking, the researchers said.

Limitations of the study include the survey’s use of nonvalidated questions, the lack of a formal clinical diagnosis of cluster headache, and the grouping of all triptans, rather than assessing individual triptan medications, such as sumatriptan subcutaneous, alone.

The study received funding from Autonomic Technologies and Clusterbusters. One of the authors has served as a paid consultant to Eli Lilly as a member of the data monitoring committee for clinical trials of galcanezumab for cluster headache and migraine.

This article was updated 3/7/2019.

SOURCE: Pearson SM et al. Headache. 2019 Jan 11. doi: 10.1111/head.13473.

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