
This is true for over-the-counter medications like Excedrin and BC powders, as well as prescription medications like Fiorinal, Midrin, and “triptans” like
Imitrex, Zomig,
Relpax, Frova, etc. Exactly why this occurs is unclear, but it is a well established clinical finding. Anyone who takes pain medications more than twice a week is in danger of perpetuating their headaches. Occasional usage of pain medications several times in one week is permissible, as long as it is not a regular pattern.