Caffeine can be considered a drug since it is available in a pure form in tablets and injections. It is also included in medications, such as Excedrin, Fioricet, and Fiorinal. It is considered to be an analgesic adjuvant, meaning that it enhances the effect of other pain medicines, such as aspirin and acetaminophen, but it has been shown to relieve tension-type headaches by itself as well. However, there are no studies showing that caffeine alone taken by mouth relieves migraine headaches. It does enhance the effect of acetaminophen and aspirin in Excedrin and this combination has been proven to relieve mild and moderately severe migraines.
In a pilot open-label study of intravenous infusion of 60 mg of caffeine citrate for an acute migraine showed significant relief within an hour of infusion. The study was published in 2015 in the Journal of Caffeine Research (who knew such a journal existed).
Besides caffeine, Fioricet, Fiorinal, and Esgic contain either acetaminophen or aspirin and butalbital, which is a barbiturate. Barbiturates are used for epilepsy, anesthesia, and in the past had been used for insomnia. However, they are addictive and they are no longer widely used. However, butalbital’s use in headache products stubbornly persists despite its addictive nature and lack of proof that it relieves migraines. These products can cause not only addiction, but also medication overuse headaches, most likely due to their caffeine content.
Caffeine can cause headaches directly, but much more often the headache is due to caffeine withdrawal when it is consumed for long periods of time in large amounts. Caffeine withdrawal headaches have been proven to occur in a double-blind withdrawal study. Most people who drink a lot of coffee know this from their personal experience – skipping the morning cup or not drinking coffee on days of fasting leads to a bad headache, which is usually a migraine. Sometimes caffeine withdrawal headaches are not obvious. Someone who drinks two cups of coffee and two caffeinated sodas daily may not realize that their daily headaches are caffeine-related. They just take Excedrin, which provides temporary relief, but adds fuel to the fire.
Some people develop tolerance to caffeine, which means that the stimulating effect lasts shorter and shorter periods of time and such individuals have to drink more and more coffee to maintain its effect. This ends up in needing 10 cups of coffee or 10-20 tablets of Excedrin daily. My record-holder was a patient who was taking about 25-30 tablets of Fioricet daily and had to be hospitalized for detoxification.
The bottom line with caffeine is that it helps when used occasionally and worsens headaches when taken more than a few times a week.
