When should I take Imitrex (sumatriptan) tablets? When I get the aura, or when I begin to feel the pain? Also, can the 100 mg caplets be split in two or does it affect the delivery of the medicine into the body? I've been taking it when I get the aura, but I can get the aura with or without pain. (I don't take this for other types of headaches, which I don't get often anyway; I only take it when the pain is definitely one-sided, and usually follows the aura.) Thanks!!!