Inclusion Criteria:

• Diagnosis of migraine (with or without aura) according to the criteria of the International Headache Society.
• Age at onset of migraine less than 45.0 years.
• Males and females between 18.0 and 65.0 years of age inclusive.
• Be willing and able to give written informed consent.
• For female patients, a negative pregnancy test
• Sexually active participants and their partners should be using an effective method of contraception; combined hormonal or progestogen-only methods, IUD/IUS, diaphragm/condoms with spermicide or sterilisation.
• History of 1-6 migraine attacks per month (with or without aura) in the 3 months prior to screening, with at least 48 hours freedom from headache between attacks.
• Patients receiving migraine prophylactic treatment can be enrolled, providing they are receiving only one drug for prophylaxis and the prescribed daily dose is not changed in the month prior to screening.
• Rescue medication is permitted in the study.
• Women with menstrual migraine (or who have suspected menstrual migraine or are subsequently diagnosed with menstrual migraine) may be included in the study and instructed to treat each consecutive attack with study medication (unless within the wash-out period).
• Patients who are willing and able to comply with study requirements including completion of the study diary.
• Patients who are taking prescribed medication for depression may be included providing this treatment has been stable for 3 months prior to screening and is expected to remain stable for the duration of the study.
• In the investigators opinion are suitable for inclusion in the study.

Exclusion Criteria:

• Patients with ≥15 headache days (migraine and non-migraine headaches combined) per month.
• Patients who take analgesics for any reason ≥15 days a month or triptans ≥10 days a month.
• Non-migraine headaches on more than 6 days per month.
• Patients with schizophrenia.
• Patients prescribed more than one migraine prophylaxis treatment.
• Patients receiving prophylaxis whose prescribed daily dose has changed within the month before screening.
• Patients whose prophylactic treatment is not expected to remain stable for the duration of the study.
• Patients whose prophylactic treatment has been withdrawn within the month prior to study entry.
• Patients taking ergotamine, ergotamine derivatives or ergotamine combination products.
• Any relevant abnormality on history or examination including central nervous system, psychiatric (excluding depression), respiratory, cardiovascular or metabolic dysfunction.
• Abnormal laboratory findings suggesting infectious, endocrine, malignant disease or other systemic disorder; any isolated abnormal laboratory finding considered clinically relevant by the investigator at screening.
• Subjects with clinically significant abnormalities in 12-lead electrocardiogram (ECG), blood pressure and/or pulse at screening.
• Recent or clinically significant history of drug or alcohol abuse.
• Inability to communicate well with the investigator (ie, language problem, poor mental development or impaired cerebral function).
• Participation in a clinical study of an Investigational Medicinal Product (IMP) within the 3 months up to screening.
• Patient unable to commit to participating in the clinical study for up to 8 months or patient expecting any medical interventions during that time.
• Patients taking prescribed medication for depression, whose treatment has not been stable for 3 months up to screening and is not likely to remain stable for the duration of the study.
• Female patients who are pregnant or lactating.
• Patients taking any unapproved herbal remedies for treatment of depression or migraine e.g. feverfew, St Johns Wort. (Supplementary vitamins, minerals or homeopathic remedies will be permitted provided their intake is kept constant throughout the study).
• Patients with a history of lactose intolerance.