In answering the question What are Generic Drugs? on its Web site, the Food and Drug Administration states unequivocally: “A generic drug is identical, or bioequivalent to a brand name drug in dosage form, safety, strength, route of administration, quality, performance characteristics and intended use.”
If you check the Oxford Dictionary, you will find this definition for the word “identical:”
adj. 1 agreeing in every detail. 2 one and the same. The Merriam-Webster Dictionary defines identical as 1: being the same 2: having such close resemblance as to be essentially the same.

Given such definitions, it’s only logical that patients, physicians and pharmacists would assume that all generic drugs are exactly the same as their brand name counterparts. The reality, however, is not so clear.
For one thing, the FDA does not require generic drugs to contain the same inactive ingredients as the brand name product. That means colors, binders and fillers (that often make up the majority of the pills) can be quite different. In some cases this may mean someone is allergic to one formulation of a generic drug even though he tolerates the brand name.

Many pills are designed to release the active ingredient over a sustained period of time. Generic products may use a different formulation. This could alter the way in which the medicine gets into the blood stream.

A few years ago we started hearing from readers of this column that the generic drug Budeprion XL 300 was affecting them quite differently from the brand name Wellbutrin XL 300. When we investigated, we learned that the generic used a different technology to control the release of the active ingredient bupropion. This resulted in the drug getting into the blood stream faster.

Here is just one of the hundreds of stories we have received about this: “Wellbutrin XL has worked wonders for me. Recently, however, my insurance provider substituted Budeprion for the Wellbutrin and my experience has been awful. Soon after starting it I began having feelings of despair, hopelessness, disorganized thinking, anxiety and depression.

“I’ve had physical problems as well: migraines of greater duration and intensity, sleep disturbances and night sweats. All of these changes coincide with my taking Budeprion. I have resumed taking Wellbutrin and I am feeling better and thinking more clearly.”

Readers have also reported problems with other generic formulations. The generic form of the heart and blood pressure pill, Toprol XL, has produced dozens of complaints: “I've taken Toprol XL for 11 years. When my insurance company dropped the name brand for generic metoprolol, the pharmacy re-filled without advising me. I noticed the change once my blood pressure went through the roof along with pounding heart rate, flushing and very swollen ankles. I was weak and dizzy. I demanded the pharmacy give me the correct prescription; after two months I was back to normal.”

You can read more stories at Anyone who has a problem with a generic drug can report it to us or directly to the FDA at

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  1. Bonnie

    I am supposed to switch from Neurontin brand name to gabapentin this month because my insurance no longer covers the brand. I am very scared. I have done very well on Neurontin and have never had a seizure. Now, I am reading horror stories on the web about reactions and even incidents of seizures with some of the generic versions. Does anybody have information on which version of gabapentin works best and is most effective? I read that generics manufactured in India can be a problem. Please advise and thank you.

  2. Carol

    Several years ago I started on the name brand Wellbutrin. When switched to the generic I did not notice much difference and have been taking a yellow Bupropion tablet (not sure of manufacturer). The last time my prescription was filled it was a white colored Buprprion and I noticed the difference right away and it was not good.
    So this last time I went to the pharmacy and complained about my experience. Since they no longer carried the yellow generic, the pharmacist found another generic that was a purple/brownish colored tablet. It is the best of the generics that I have taken.
    If your pharmacist is willing to work with you, I suggest sampling a couple generics before going back to the name brand as there seems to be a difference even in generics and it is worth not having to pay those high prices for the name brand. I will be cognizant of any changes in mood from here on out just in case this more recent bupropion proves ineffective.

  3. karen

    I have been taking Topamax for years for pain management due to nerve damage. My company changed to United Health Care, they (United) are insisting that I use the generic form of the drug. I tried it in Feb., I could not tolerate the drug because I had a migraine every single day. I took it for 3 weeks, finally my doctor and I said Enough of this, so she put me back on Topamax. At the end of April United pulled the plug w/o telling me or my doctor why.
    My doctor’s office thought it would be up for review at the end of July. This company has 3 levels of drugs, any drug in the 3rd level has to be justified ever so many months. 2 of mine are in the 3rd level. I have yet been able to get back on Topamax, my doctor said Friday she does not want
    me to be on generic because a migraine everyday is not acceptable. I have talked to the company several times a week about this, sometimes 4 or 5 times a day. I have had 4 back surgeries (fusions), both total knees replaced, 2 foot surgeries. I also have Arthritis in my spine.
    I can’t understand Why the company would fight this battle, they said Friday that my Dr. can send an appeal for my and say that I am allergic to the drug. By the way, the CEO of United made 24 million last year with I believe an addition 7 million in stock options. Guess he sleeps well at night!

  4. Laina

    Hope you try buying Greenstone gabapentin at Costco. You do NOT have to be a member but you will have to persistently insist on that generic only. They normally have to special order it. Double check when you pick it up!! On another problem… with cervical dystonia for 16 years taking gab. for 14 yrs. I seem to be having muscle spasms and cramping this past year. My specialist at Ohio State Medical retired and I cannot trust any others here where I moved. And I have tried. My internist that is out of state re ups my 2 Rxs after I see him once a year and he knows more (he made it a point to read up on it too) than the ‘specialists’ here in SW FL.
    I always had that fear one day it would stop working for me….that day seems to be here. I may try the Pfizer capsules (God help me with paying for it) next time in a small amt. and see what, if anything, happens.
    Again…Costco for the best price on Greenstone gabapentin.

  5. RR

    I want to add my experience with the generic drug Propranolol ER. I have been taking this medication once per day for over 10 years now for my anxiety. I take the 80 mg dosage. I have had no issues with the name brand Wyeth/Pfizer version and the generic version made by Upsher-Smith. However, I have had 2 instances where the pharmacy dispensed the generic version made by another company that I will not mention here and after taking the capsules for about 4-7 days, I experience severe side effects. Those side effects include severe anxiety, hot flushing and obsessive thoughts and noticeable shaking in my hands.
    Each time I call my Psych Dr and he puts in a call to the pharmacy to prescribe and dispense the aforementioned brand. After a few days of being back on that my issues go away and I am good to go. I have thought about calling the manufacturer about my issues with their product but I feel like my concerns will probably be ignored. I can attest from my own experiences there can be side effects from different generic versions of the same medication.

  6. LD

    I have severe neuropathy. I take percocet 10/325 up to 5 times a day, depending on pain level; 2 60mg morphine sulfate ER twice a day, and 2 600mg neurontin (gabapentin) 3 times a day. The gabapentin was added last, about a year ago and has really been helping. The color of the pills I’ve been taking was blue. Recently, my drug company has forced me into getting gabapentin through the mail, 90 days worth at a time, evidently to save them money.
    I just got the first batch of mail order pills and the color is white. I’ve been taking them for a week now, and my neuropathic pain has gotten much, much worse. Can you tell me if there’s a chemical difference between the blue and the white gabapentin pills? Is there any way I can request the drug company to get me back on the blue pills? Thank you so much for your help.

  7. JD

    No way, I have had both and the name brand is for sure stronger.

  8. No Stress

    One supplier in NY of a gabapentin generic did not work for me.
    It might have been a polymorph of the correct molecule.
    It may have worked for other people, but not me.
    Twice CVS switched me to that supplier without telling me
    and twice I had to go back to them and complain.
    Eventually I had to go to Riteaid to get the gabapentin from
    a different supplier since CVS would only sell the one that didn’t work.
    Now CVS has taken over the local Riteaid customers and
    I have to find a different pharmacy again.

  9. Tara

    I find this article to be helpful. I had been on Wellbutrin XL for years, with great success. Some side effects that I found unpleasant though. Mainly sweating. I decided to try other medications for depression to avoid the side effect from Wellbutrin. I tried many. They all made me feel like a walking zombie. So I decided I would deal with the sweating and go back to Wellbutrin.
    My insurance out me on Bupropion (generic). There is such a remarkable difference in the effects between the two. I am having completely different results on the Bupropion than the Wellbutrin.
    This is just my opinion on the observations of my own body and the medications. Everyone reacts to medications differently. Some may love the Bupropion, others may feel the same way I do.
    But in my opinion from experience…..there is a DIFFERENCE!!!!

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