The effect of blood pressure lowering medications on the prevention of episodic migraine : a systematic review and meta-analysis

Background: Currently, only a few specific blood pressure-lowering medications are recommended for migraine prevention. Whether benefits extend to other classes or drugs is uncertain. Methods: Embase, MEDLINE, and the Cochrane Central Registry of Controlled Trials were searched for randomized control trials on the effect of blood pressure-lowering medications compared with placebo in participants with episodic migraine. Data were collected on four outcomes – monthly headache or migraine days, and monthly headache or migraine attacks, with a standardised mean difference calculated for overall. Random effect meta-analysis was performed. Results: In total, 50 trials (70% of which were crossover) were included, comprising 60 comparisons. Overall mean age was 39 years, and 79% were female. Monthly headache days were fewer in all classes compared to placebo, and this was statistically significant for all but one class: alpha-blockers −0.7 (95% CI: −1.2, −0.1), angiotensin-converting enzyme inhibitors −1.3 (95% CI: −2.9, 0.2), angiotensin II receptor blockers −0.9 (−1.6, −0.1), beta-blocker −0.4 (−0.8, −0.0) and calcium channel blockers −1.8 (−3.4, −0.2). Standardised mean difference was significantly reduced for all drug classes and was separately significant for numerous specific drugs: clonidine, candesartan, atenolol, bisoprolol, metoprolol, propranolol, timolol, nicardipine and verapamil. Conclusion: Among people with episodic migraine, a broader number of blood pressure-lowering medication classes and drugs reduce headache frequency than those currently included in treatment guidelines. Trial Registration: The study was registered at PROSPERO (CRD42017079176).