Final answer:
Sumatriptan is an abortive drug for migraines that constricts blood vessels and reduces inflammation in the brain.
Step-by-step explanation:
An abortive drug for migraines is a medication that is used to stop a migraine attack once it has started. One example of an abortive drug for migraines is sumatriptan, which is a medication that constricts blood vessels and reduces inflammation in the brain. It is often taken as a tablet, nasal spray, or injection.