Caffeine and Headache
Caffeine acts as a stimulant by displacing adenosine in the brain. Notice the similarity of the words “caffeine” and “adenosine”. Adenosine, you may remember from high school biology, is involved in ATP (adenosine triphosphate) and energy cycling in cells. However, the actions of caffeine are complex, and are not fully understood.
Excerpt from the Wikipedia Caffeine article relevant to headache:
“Because adenosine, in part, serves to regulate blood pressure by causing vasodilation, the increased effects of adenosine due to caffeine withdrawal cause the blood vessels of the head to dilate, leading to an excess of blood in the head and causing a headache and nausea. This means caffeine has vasoconstriction properties.[92] Reduced catecholamine activity may cause feelings of fatigue and drowsiness. A reduction in serotonin levels when caffeine use is stopped can cause anxiety, irritability, inability to concentrate, and diminished motivation to initiate or to complete daily tasks; in extreme cases it may cause mild depression. Together, these effects have come to be known as a "crash".[93]
Withdrawal symptoms — possibly including headache, irritability, an inability to concentrate, drowsiness, insomnia and pain in the stomach, upper body, and joints[94] — may appear within 12 to 24 hours after discontinuation of caffeine intake, peak at roughly 48 hours, and usually last from one to five days, representing the time required for the number of adenosine receptors in the brain to revert to "normal" levels, uninfluenced by caffeine consumption.”
Frequenly asked questions about caffeine and headache:
from Charles Matthews M.D.
Director, the North Carolina Comprehensive Headache Clinic
1) How do I know if caffeine is causing my headaches?
Caffeine probably does not cause headaches unless you are susceptible to it. However, a daily caffeine habit is probably the most common cause of worsening headaches.
2) What types of headaches are worsened by caffeine?
Tight muscle contraction morning headaches are the most common headaches caused by caffeine. In people suffering from migraine, daily use of caffeine usually first causes an additional low-grade morning headache, and then a gradual increase in the frequency and severity of intermittent migraines.
3) Does caffeine cause cluster headaches?
Caffeine does not appear to cause or affect cluster headaches. However, we have seen patients with well-defined cluster headache who develop an additional daily morning tight headache that resolves when caffeine is stopped.
4) Is there a test to see if caffeine is causing some of my headaches?
Yes, you can completely stop caffeine for three days. If your headaches worsen durng that time, it’s certain you will benefit from stopping caffeine completely for a longer period of time.
5) Can I just cut down?
No, your receptors will not reset until you completely “cold-turkey” the caffeine. Actually, it’s necessary for your receptors to “complain”, to experience the withdrawal of caffeine, in order to “reset”. So, in caffeine withdrawal, no pain, no gain.
6) Do I have to stay off of caffeine forever?
That’s not necessary in most cases. Once your receptors have reset (typically three days, occasionally as long as a week) you can return to taking caffeine two days a week. In order to prevent the return of a caffeine habit and caffeine-withdrawal headaches, you must remain completely free of caffeine five days each week.
7) Why two days a week?
There’s no evidence that drinking caffeine two days each week will affect your headache frequency over time. But, at three days each week, the risk of returning to increased headache frequency rises.
8) What contains caffeine?
Coffee, teas (except some herbal teas), and soft drinks. Also, many OTC pain medications, such as Goody's Powders and Excedrin Migraine, also contain caffeine, so if you take one of these medications this counts as one of your caffeine days. So, one cup of coffee on Saturday, one on Sunday, and one Excedrin Migraine on Wednesday, and you’re over the limit.
9) Chocolate contains a little caffeine. Should I avoid chocolate too?
I think chocolate is fine. It seems to be the liquid forms of caffeine that are the problem. Unless you have noticed that chocolate triggers headache in you particularly, go ahead and enjoy all you like. I’m a Headache Specialist, not the food police!
10) How about decaf drinks?
Decaf sodas are fine. (Some, however, are sensitive to artificial sweeteners which contain substances that act like excitatory neurotransmitters and may worsen headache.) I’m a little hesitant to say it, but probably decaf coffee and tea don’t cause problems in people who are not already addicted to caffeine; if you are trying to withdraw from caffeine, yo’ull have to avoid decaf coffee and tea too.
If you would like to return to decaf coffee, we recommend that you wait until your headaches are under control, and then cautiously return to decaf coffee. If there is any question, stop for three days and see if your headaches worsen.
11) When can I return to taking some caffeine?
It’s best to wait until your headaches are under control. At that time, you can return to two days each week.
12) I’ve been off caffeine completely for three months. Just like you said, I had terrible headaches for three days, then I got much better. The bad thing is I just love sweet tea, and every Sunday we go to Grandma’s and have a big dinner, but I always avoid the tea. I miss it. How am I doing?
Well, pretty good, but I think you’re missing out on that sweet tea, which you enjoy. Remember, the important thing is that you remain completely free of caffeine for five days each week. That means, on the other two days you can have as much caffeine as you like. So, I think you’re avoiding your Grandma’s tea unnecessarily.
13) So, can I drink 10 glasses of sweet tea on Sunday and I won’t get headaches?
Yes, that’s right. And Saturday too, as long as you don’t drink any at all the rest of the week.
14) Is it better if I drink just two glasses at the picnic?
I don’t think so. You see, what matters is how long your receptors are clean of caffeine. So, once you have some caffeine that day, go ahead and enjoy it. That’s one day. You get no extra points for having less on your caffeine days.
15) So, it’s OK to binge two days a week, but I can’t have a habit?
You got it!
16) Same thing with Goody’s Powders and Excedrin Migraine?
Yep. You can take up to recommended doses on the bottle on Saturday, and also on Sunday, and drink caffeine those days as well, but you have to stay off caffeine and caffeine containing pills the rest of the week.
17) Could caffeine have prevented me from responding to previous medication?
Yes! If you tried a medication that didn’t work (for example, your doctor put you on Topamax and it didn’t work, but you had a caffeine habit at the time) the reason why it did not work may have been the caffeine. It’s often worth retrying a medication you previously did not benefit from.
18) What happens after quitting caffeine?
We have to just wait and see. People whose headaches worsen when they quit caffeine always get better- somewhere from 30% to 80% better. And most importantly, any headaches you have after quitting caffeine will be different. They may be a different quality, more like when you first started having headaches, and before they got worse. Often, they are more intermittent, more like a standard migraine, the daily morning headache often goes away. and the “original” headache will be much more responsive to treatment. I recommend reassessing any remaining headache condition after the caffeine withdrawal is complete.
19) How is it that caffeine helps headaches, and also makes them worse?
The short and very oversimplified answer is that caffeine is a vasoconstrictor, and can reduce the vasodilation phase of a headache associated with the pounding feeling. However, with a caffeine habit, the blood vessels “adapt” to this level of caffeine, and the vessels excessively dilate when the caffeine is withdrawn.
The long answer involves the fact that migraine isn’t really primarily a disorder of the blood vessels as was thought a few decades ago. Neuroscientists tend to consider brain learning, adaptation, addiction, and habituation as actions of the brain that are mediated through complex long term cellular changes , and even a small caffeine habit disturbs this process.
20) What if I can’t stop caffeine on my own?
Many people who cannot come off of caffeine have a serious underlying problem with fatigue, sleep disturbance, or other condition that must be treated first in order to tolerate caffeine withdrawal. Some have responsibilities that can’t be put down for three days of caffeine withdrawal, such as child care or work. In these cases, we first investigate the cause of fatigue, put preventative approaches in place, and then plan for a time when caffeine withdrawal can be done, perhaps over a holiday.
21) What is the chance that stopping caffeine will really help me?
Good question! Many people with headache have already been told to do things which have not really helped them, and they are understandably skeptical. In patients whose migraines are primarily around the menses, for example, and who do not have a daily low grade headache, stopping caffeine probably won’t help.
if we recommend caffeine withdrawal, your chances of almost eliminating your low-grade daily headache in our clinic is approximately 90%, and we expect an additional reduction in migraine frequency from 30% to 80%. That’s a big deal, and it’s worth it.
