Intranasal ketamine seems effective for refractory chronic migraine, with about half of patients reporting it as very effective, according to US findings.

Researchers from Thomas Jefferson University in Philadelphia conducted a retrospective study at a tertiary headache centre to examine the effectiveness and tolerability of intranasal ketamine for chronic migraine.

A total of 242 patients received intranasal ketamine between January 2019 and February 2020, with 169 of those patients interviewed, in the study in Regional Anesthesia and Pain Medicine.

Participants reported a median of 30 monthly headache days and tried four classes of preventive medications.