R-Verapamil for the Prophylaxis of Episodic Cluster Headache

Inclusion Criteria: * Healthy man or woman between the ages of 18 and 65 * In good health as determined by medical history and medical examination * Has a diagnosis of episodic cluster headache as defined by the International Classification of Headache Disorders (2nd edition) * Has a lifetime prevalence of at least 2 prior cluster bouts - Subjects must experience at least 7 attacks/week during the run-in baseline period * Subjects must have a typical cluster period lasting at least 1 month. Subjects must be present in active cluster period and the expected remaining duration of the cluster cycle must be at least 3 weeks from Baseline Day 1 visit * Able to differentiate other headache types from cluster headaches * Is using or agrees to use a medically acceptable form of contraception(female of child-bearing potential) * Negative urine pregnancy test prior to study entry(female of child-bearing potential) * Concomitant medication that, in the opinion of the investigator and the patient's general practitioner(GP), do not pose an unacceptable risk based upon the prescribing information for verapamil * Able to understand and comply with all study requirements * Written informed consent Exclusion Criteria: * Women who are pregnant or lactating * Subjects who, in the investigators opinion, have a history or have evidence of a medical or psychiatric condition that would expose them to an increased risk of a significant adverse event or would interfere with the assessments of efficacy and tolerability * Use of any drug or having any medical condition which might interact adversely with, or interfere with the action of, the study medication * The concomitant use of beta blockers * The consumption of grapefruit juice * Allergic to or has shown hypersensitivity to verapamil or agents similar to verapamil * Abuses opioids or has a history of significant drug or alcohol abuse within the past year as determined by investigator * Has participated in an investigational drug trial in the 30 days prior to the screening visit * Has liver or kidney disease * Has a cardiopathology contraindicating verapamil administration * Subjects with previous adynamic ileus. * Subjects with chronic cluster headache * Use of antipsychotic, antidepressants, lithium or other prophylactic treatment less than one month prior to inclusion