<prompt> All of the following drugs are used in Migraine prophylaxis EXCEPT:PropranololSumittriptanFlunarazineCyprohaptidine  <response>: B Sumittriptan Sumatriptan is structurally similar to serotonin 5HT, and is a 5-HT types 5-HT1D and 5-HT1B agonist. Specific receptor subtypes it activates are present on the cranial arteries and veins. Acting as an agonist at these receptors, Sumatriptan reduces the vascular inflammation associated with migraine. The specific receptor subtype it activates is present in the cranial and basilar arteries. Activation of these receptors causes vasoconstriction of those dilated arteries. Sumatriptan is also shown to decrease the activity of the trigeminal nerve, which, it is presumed, accounts for sumatriptans efficacy in treating cluster headaches. It is given at the onset of an attack. 