Imitrex and Topamax are two migraine medications that recently lost their patent protection and became available in a generic form, under the names of sumatriptan and topiramate. Many patients are concerned about the quality of generic products. A recent study published in Neurology looked at 948 patients with epilepsy who were treated with generic Topamax (it is approved for the treatment of both migraines and epilepsy). Compared to patients who used the branded Topamax, those on generic substitutions needed to have more of other medications, were admitted to the hospital more frequently and stayed in the hospital longer. The risk of head injury or fracture (presumably due to seizures) was almost three times higher after the switch to a generic drug.
Clearly, migraine patients do not run the same risk as epilepsy patients of having a seizure or being admitted to the hospital, however a small number of patients can have worsening of their migraines. The main reason is the legally permitted variation in the amount of medicine in each tablet. Taking a higher dose of the generic drug can help.
The same applies to Imitrex – a small number of patients will find that the generic sumatriptan is slightly less effective. The only, albeit significant, advantage of the generic drugs is cost savings. At this point we have only one generic substitution for Imitrex and the price difference is only 20%, but in a few months more generics will appear and the price should drop significantly, which is a very welcome development for patients with frequent migraines.
