Verapamil is a calcium channel blocker widely used to treat cardiovascular diseases however it is also the first line treatment in the prevention of cluster headaches. In France, its prescription in that indication is based on compliance with the Temporary Recommendation for Use (RTU) that insists on the possible the cardiac side effects that can occur as the doses required for cluster headache are significantly higher than the doses used in cardiology.

Inclusion Criteria:

• patient 18 years old, and older
• patient suffering from Cluster Headache (according to the l'ICHD-3 diagnostic criterias)
• patients affiliated to the social security
• patient that has given his full written consent to participate in the study
• female patients participating in the study must be using an efficient contraception for more than 1 month prior to the beginning of the study

Exclusion Criteria:

• patient presenting contraindications to the use of verapamil
• patient observing a treatment with ivabradine (Procoralan®), bétablockers, colchicine, l'esmolol, triazolam, quinidine.
• patient under justicial protection
• patient breastfeeding, or pregnant
• patient suffering from a neuromuscular transmisson disease
• patient with a pacemaker

No data sharing plan ahs been established