For acute treatment of cluster headaches, which is commonly used?

For the acute treatment of cluster headaches, the use of 100% oxygen is highly effective and is a well-established first-line therapy. When inhaled, oxygen helps to alleviate the pain associated with cluster headaches, likely through vasoconstriction and the reduction of inflammation. The mechanism is not entirely understood, but studies have demonstrated that administering oxygen at a high flow rate can significantly reduce headache intensity and duration in many patients.

Other treatments for cluster headaches include triptans, which can also be effective, but they were not included in your choices. Topiramate, although a preventive medication, is not used for acute attacks. Similarly, ibuprofen and codeine are not considered effective acute treatments for cluster headaches. As such, 100% oxygen remains the preferred option due to its rapid onset of relief and safety profile.