Generic medications

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.

  1. Dr. Mauskop says: 06/08/20108:33 am

    I do not have names of all manufacturers or which ones are better or worse. The two I am aware of are Ranbaxy, whose plants were cited by the FDA as non-compliant and whose sumatriptan version of Imitrex I would avoid, and the second one is Dr. Reddy’s whose sumatriptan seems to be very good. You usually cannot request different generics at a pharmacy (especially the big chains) because many carry only one generic, but you can go to a different pharmacy which may carry a different generic.

  2. Christine says: 06/07/20107:42 pm

    Dr. Mauskop:
    I am going to have to switch to the generic form of Imitrex.
    You mentioned that out of a number of different manufacturers, there are a couple that are clearly less effective.
    It would be really helpful if you could let me know a couple of manufacturers to either look for or to avoid. I never knew that I could request a certain manufacturer at the pharmacy.
    Thanks for your help!!

  3. Dr. Mauskop says: 03/30/20102:07 pm

    Yes, I do see some patients for whom generic Topamax does not work as well and for many of them raising the dose makes it effective again. Since my post in June of last year the number of generics for Imitrex has increased to 10 and at least one or two are clearly less effective than the brand or other generics. Once you find a generic product that works for you find out who the manufacturer is (it is usually mentioned on the pharmacy label) and ask for the same manufacturer’s product every time.

  4. Anna Kupis says: 03/30/20101:24 pm

    I just want to say: I knew it! My migraines have become worse just around the time I was switched to generic Topamax. I spent hours online searching for any studies that would suggest generic is slightly less effective but couldn’t find anything. I upped my dose by 25mg in the meantime but that didn’t help so far. Finally I read this post. Now I’m wondering if I should go up by another 25mg or try and fight my insurance company to get back on branded Topamax.

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