. 2013 May 17;9:709–720. doi: 10.2147/NDT.S33769

Table 1.

Classification of migraine preventive therapies available in the US

Level A: medications with established efficacy (at least class I trials)	Level B: medications are probably effective (one class I or at least two class II studies)	Level C: medications are possibly effective (one class II study)	Level U: inadequate or conflicting data to support or refute medication use	Other: medications that are established as possibly or probably ineffective
Antiepileptic drugs^a	Antidepressants/SSRI/SSNRI/TCA	ACE inhibitors Lisinopril	Carbonic anhydrase inhibitor	Established as not effective
Divalproex sodium	Amitriptyline	Angiotensin receptor blockers	Acetazolamide	Antiepileptic drugs
Sodium valproate	Venlafaxine	Candesartan	Antithrombotics	Lamotrigine
Topiramate	Beta blockers	Alpha-agonists	Acenocoumarol	Probably not effective
Beta blockers	Atenolol^a	Clonidine^a	Coumadin	Clomipramine^a
Metoprolol
Propranolol
Timolol^a	Nadolol^a	Guanfacine^a	Picotamide	Possibly not effective
Triptans (MRM^b)	Triptans (MRM^b)	Antiepileptic drugs	Antidepressants	Acebutolol^a
			SSRI/SSNRI
Frovatriptan^b	Naratriptan^b		Fluvoxamine^a	Clonazepam
	Zolmitriptan^b	Carbamazepine^a	Fluoxetine	Nabumetone^a
		Beta blockers	Antiepileptic drugs	Oxcarbazepine
		Nebivolol	Gabapentin	Telmisartan
		Pindolol^a	TCAs
		Antihistamines	Protriptyline^a
		Cyproheptadine	Beta blockers
			Bisoprolol^a
			Calcium blockers
			Nicardipine^a
			Nifedipine^a
			Nimodipine
			Verapamil
			Direct vascular smooth muscle relaxants
			Cyclandelate

Notes:

Classification based on original guideline and new evidence not found for this report;

for short-term prophylaxis of MRM.

Abbreviations: ACE, angiotensin-converting enzyme; MRM, menstrually related migraine; SSNRI, selective serotonin–norepinephrine reuptake inhibitor; SSRI, selective serotonin reuptake inhibitor; TCA, tricyclic antidepressant.