###Human: Will taking Sibelium for migraine delay the periods? ###Assistant: Hello. On the aspect of missing your period can be Sibelium (Flunarizine) because it has some effect of blocking the dopamine receptor in the brain. Besides, it is a calcium channel blocking effect. So the possibility is that by blocking the dopamine receptor that will cause a central increase of prolactin. Prolactin will lead to galactorrhea and in turn, alter the menstrual cycle. So it is a possibility that is if you have done a pregnancy test and it is negative. So that dopaminergic antagonistic may cause amenorrhea.