Are over-the-counter medications for migraine effective?

Yes. Most headaches can be managed with otc meds. If the headaches are persistent and occurring frequently then you should have further eval and discuss with pcp. Be careful with excedrine and other meds containing caffeine. These can cause rebound headaches if taken chronically.
Yes. They can be. Excedrine migraine can be very effective. If they do not work for you then see your doctor.
Yes! Excedrin migraine and over-the-counter anti-inflammatory medicine like ibuprofen, naproxen, Ketoprofen all work well for many people. Sometimes a little caffeine or chocolate does just the trick [unless those are migraine triggers for you!]. Talk with your doc about prevention if your headaches are frequent, severe, your meds don't work, or it's changing your life. Good luck.
For some people. Over-the-counter medications can be very effective for some migraines in some people. Many people get relief from medications like ibuprofen or acetaminophen. Combination medications such as Excedrin Migraine or Bayer Migraine formulas, which contain aspirin, acetaminophen and caffeine are particularly effective in some individuals. For more informaition see: http://understandingmigraine.blogspot.com/