Candesartan for Migraine Prevention:

Prior treatment

• Chronic migraine, chronic tension-type headache, medication overuse headache or other headache occurring on ≥ 15 days/month
• Current use of antihypertensive medication
• Use of medicines for migraine prophylaxis less than 4 weeks, or of botulinum toxin less than 16 weeks, prior to start of study
• Having tried ≥ 3 prophylactic drugs against migraine during the last 10 years
• Previous use of candesartan
• Requiring detoxification from acute medication (triptans, opioids)
• Consistently failing to respond to any acute migraine medication
• Alcohol or illicit drug dependence.

Other illness

• Hypersensitivity to candesartan
• History of angioneurotic oedema
• Primary hyperaldosteronism (Conn's syndrome)
• Significant psychiatric illness

Lab values

• Current use of potassium supplements

Other

• Interval headache not distinguishable from migraine;
• Pregnancy, planning to get pregnant, inability to use contraceptives, lactating
• Clinical information on or signs of cholestasis or decreased hepatic or renal function. If in doubt, relevant blood tests should be performed
• High degree of comorbidity and/or frailty associated with reduced life expectancy or high likelihood of hospitalization, at the discretion of the investigator
• Current use of spironolactone
• Inability to understand study procedures and to comply with them for the entire length of the study

• Signed informed consent
• Episodic migraine with or without aura according to ICHD-3 criteria
• At inclusion, patients should retrospectively have from 2 to 8 migraine attacks per month during the last 3 months. This frequency must be confirmed in the headache diary before randomization to treatment.
• Debut of migraine at least one year prior to inclusion
• Start of migraine before age 50 years
• No use of other migraine prophylactics during the study
• For women of child-bearing potential, use of highly effective contraception.