Rebound occurs when a drug is used, or overused, and causes a headache later on, or the next day. The medicines that contain higher amounts of caffeine (such as Excedrin) are more likely to induce rebound. This is a murky area, as many patients are told that they have rebound when it is just their natural headache pattern. Some people have rebound from small amounts of caffeine, while others have no rebound from high caffeine doses.
A variety of meds may cause rebound: nsaids (ibuprofen, Advil, naproxen, Aleve), Excedrin, Butalbital (Fiorinal, Esgic), opioids (Vicodin, codeine), and triptans (Imitrex, Maxalt, Zomig, etc.). If a patient usually does not get a headache the 2nd day, and subsequently has a 2nd day headache after taking a drug, it may be from that medication. Or, some people have 2 days/week of headache, go on a new abortive med., and within months have daily (or near-daily) headaches; we then think about rebound.
We don’t know the reasons (pathophysiology) behind rebound; probably brainstem pathway connections are involved. Many patients diagnosed as “rebound” have refractory (difficult to treat headaches), the daily preventives have not helped, and they are simply treating their headache with whatever works (triptans, Excedrin, opioids, etc.). Patients often say “the doctor diagnosed me as being in rebound; I had the same headaches for 10 years before going on that drug”. We need to stop blaming the patients, just because our medications are not adequate.
The only practical management approach is to attempt to withdraw off of daily pain meds, daily triptans, and high-caffeine meds. We also need to minimize caffeine (but small amounts help headaches). A trial period of at least 4 weeks is suggested. However, when I suggest this, the usual response is “Ok, but what do I take in the meantime, I do have to function”. We try and use a combination of preventives and to minimize the abortives for at least 4 weeks. There are various strategies for withdrawing off of daily pain meds.
The bottom line is: we do not know who gets rebound, and from which drugs. It is a very individual, case by case situation. Practically, what we attempt to do, if possible, is minimize abortives.