Quote:

Keywords:cluster headache;chronic;refractory;warfarin;low-intensity anticoagulation (Headache 2011;51:713-725) Objective.— To investigate the effect of low-intensity anticoagulation with warfarin on chronic cluster headache refractory to pharmacological management. Background.— Isolated case reports on induction of remission in patients with intractable chronic cluster headache upon institution of oral anticoagulant therapy do exist. Nonetheless, evidence from randomized controlled trials on the role of oral anticoagulants in cluster headache is lacking. Methods.— Thirty-four patients with refractory chronic cluster headache were randomized to receive warfarin or placebo for 12 weeks. Warfarin was administered to achieve an international normalized ratio between 1.5 and 1.9. After a washout period of 2 weeks, patients were crossed over from 1 treatment to the other. Status of cluster headache was assessed during both treatment periods. The primary outcome measure was the occurrence of remission lasting ≥4 weeks. Results.— Seventeen (50%) patients underwent remission for ≥4 weeks during the warfarin period vs 4 (11.8%) patients during the placebo period (P = .004). This was associated with absolute risk reduction of 0.38 (95% CI = 0.18-0.58), and number needed to treat of 2.6 (95% CI = 1.7-5.5). The Kaplan–Meier curves for occurrence of remission had a hazard ratio of 5.26 (95% CI = 2.13-13.03, P = .0003). Frequency, duration, and intensity of cluster attacks were all significantly lower during treatment with warfarin (P < .01). Conclusion.— In patients with refractory chronic cluster headache, low-intensity anticoagulation with warfarin was associated with significantly higher incidence of remission and less impact of headache on patients' lives compared with placebo.

Thanks for posting this Bob, I'm not surprised as it's used as a counterpart to Verapamil so often in treatment for heart problems, but it's good to know it might do something. Printing for my neuro to read tomorrow, especially as my beast has been vicious since I had to pull off verapamil.

Quote:

Results.— Seventeen (50%) patients underwent remission for ≥4 weeks during the warfarin period vs 4 (11.8%) patients during the placebo period (P = .004).

These results confuse me.

The trial was done on people with "chronic cluster headache", which by definition means that they have gone for over a year with no remission period of over a month. So to have 4 of them suddenly turn to being episodic during a 12 week period seems to be higher than you might expect.

The percentage values also indicate (e.g. 17 of the 34 being equated to 50%) that the placebo and the trial drug were given to the entire group at some point. There is no discussion of if those with the placebo who went into remission had previously used the trial drug.

With the small sample sizes, it could be that some of the effect was due to if they were using other preventives (it's simply not mentioned). Or if one of the trial periods overlapped the start of spring or autumn which is a time of the year associated with many people starting or stopping episodes.

However the results at least indicate that this is worthy of further investigation.

I'd also be interested in what the proposed mechanism of waferin is.