SIBELIUM 10MG contains Flunarizine which belongs to a group of medicines known as calcium channel blockers, which works by preventing the narrowing of blood vessels. It is indicated to treat migraine-type headaches. Migraine is a type of headache caused by abnormal activity of brain and it affects the blood flow in the brain and surrounding tissues. Flunarizine is a selective calcium entry blocker with calmodulin binding properties and histamine H1 blocking activity. It reduces arterial and arteriolar smooth muscle spasm. It also helps to improve the flow of blood in your brain and prevents abnormal activity of muscles that trigger migraines and effective in preventing migraine attacks.