After drinking beer, can take antihistamines?

Only newer kind: The new-generation antihistamine such as Claritin (loratadine) or Allegra possess virtually no sedating effect and i don't see any problem with it. I do caution however that a rare individual may still get drowsiness from them even though in studies the incidence is no higher than taking a sugar pill. Thus try it first before you combine alcohol with it.