Nomenclature for flunarizine, cinnarizine, and lomerizine

To the Editor, Flunarizine, cinnarizine, and lomerizine have been used for the prophylactic treatment of migraine in certain countries and have been classified as calcium channel blockers (CCBs). These drugs, however, have other pharmacological characteristics in addition to those of CCBs. In addition to the T-type calcium channel blocking effect, flunarizine, cinnarizine, and lomerizine have antihistamine and anti-serotonin effects. Moreover, flunarizine and cinnarizine, but not lomerizine, have antidopaminergic effects (Table 1) (1). Other agents with antihistamine effects, such as cyproheptadine and pizotifen, are also effective in migraine prevention. In contrast, other T-type CCBs, including verapamil, diltiazem, and nimodipine, do not show a definitive migraine prevention effect. Similarly, L-type CCBs, including nimodipine, nifedipine, and nicardipine, do not demonstrate a migraine prevention effect. Appropriate nomenclature can lead to the enhanced understanding of a disease as well as the proper identification of drug mechanisms. Although the pharmacological characteristics of a drug may not explain the exact mechanisms of a particular drug function, the pharmacological characteristics of drugs with and without migraine prevention effects propose that the T-type or L-type calcium channel blocking alone cannot account for the prevention effects of migraine. It remains unclear whether histamine receptor blocking has a definitive migraine prevention effect; however, many histamine H1 and H2 receptor blocking agents show a significant effect in migraine prevention (2). Flunarizine, cinnarizine, and lomerizine were given