Are there negative effects to taking sumatriptan medicine with allergy medicine?

Imitrex (sumatriptan) & allergy ok: It's all right to take your allergy medication on the same day as your sumatriptan. There are no dangerous interactions warnings for antihistamines, leukotriene blocking agents or steroids when used in combination with sumatriptan. The only warning that comes close is a warning for the cough syrup ingredient dextromethorphan.