Some comorbid conditions may interfere with the capacity of the anti-inflammatory regimen to prevent cluster headache attacks. Some of these medical conditions include, but are not limited to: cardiac, thyroid, parathyroid, renal, hepatic, and pancreatic insufficiencies. Sub-clinical allergic reactions and sinusitis are also suspect. If you have one or more of these conditions, work with your PCP to make sure they are being treated. This may help make the anti-inflammatory regimen more effective as a cluster headache preventative.