Prophylactic Treatment With Atorvastatin for Chronic Migraine (ChronicStatinMig)

Inclusion Criteria:

1. Age 18 to 64 years

2. Signed informed consent

3. Chronic migraine according to ICHD-3 criteria (32)

4. At inclusion, patients should retrospectively have at least 15 headache days permonth wheof at least 8 migraine days during the last 3 months. This frequency mustbe confirmed in the headache diary before randomisation to treatment (See below).

5. Debut of migraine at least one year prior to inclusion based on information in thepatient record or by careful examination of previous headache history

6. Start of migraine before age 50 years.

7. No use of other migraine prophylactics during the study

8. For women of child-bearing potential (WOCBP, see below) there must be no pregnancyor planned pregnancy during the study period, and use of highly effectivecontraception (See below).

After the baseline period, just before randomisation to the study drug, inclusion criteria will be evaluated once more, and the headache diary will be evaluated. If there are, according to the headache diary, fewer migraine days than 8 per month, the baseline period can be extended to 8 weeks.

Exclusion Criteria:

1. Medication overuse headache requiring detoxification from acute medication (triptans, opioids). Exception could be made for those fulfilling A and B: A. Have tried a withdrawal period of at least 2 months without impact on headachefrequency B: Use of opioids (of any type) ≤ 8 days /months.

2. Pregnancy, planning to get pregnant, inability to use contraceptives (See inclusioncriteria, point 8), and lactating

3. Clinical information on or signs of cholestasis or decreased hepatic or renalfunction.

4. High degree of comorbidity and/or frailty associated with reduced life expectancy orhigh likelihood of hospitalization, at the discretion of the investigator

5. Hypersensitivity to statins or previous use of statins

6. History of angioneurotic oedema

7. Use of medicines for migraine prophylaxis less than 4 weeks, or of botulinum toxinless than 16 weeks, prior to start of study

8. Current use of antiviral treatment agaist hepatitis C

9. Significant psychiatric illness

10. Alcohol or illicit drug dependence.

11. Inability to understand study procedures and to comply with them for the entirelength of the study

12. Treatment for hypothyroidism

13. Lactose intolerance