• chronic cluster headache;
  • gabapentin;
  • long-term response;
  • prophylaxis

Chronic cluster headache (CCH) is a rare but challenging condition. About 20% of CCH patients get refractory to treatment. Gabapentin has recently been reported to be efficacious in the treatment of CCH. To test the potential of gabapentin as second-line drug, we prospectively studied the efficacy of gabapentin as add-on drug in eight patients suffering from CCH refractory to first-line treatment. Six of eight CCH patients responded to treatment. After the end of the study phase, the patients’ clinical course was further followed up until January 2006. The longest period of being continuously pain-free under gabapentin treatment was 18 months. In some individuals, increasing doses were needed with time. We conclude that gabapentin may be offered as treatment trial in patients refractory to first-line treatment. However, patients may fail to respond to treatment and drug tolerance may occur with time.