I can buy 300 10-mg tablets of Loratadine for about $15, and 90 10-mg tablets of Claritin™ costs about $35. These days my health insurance charges me $50 for the name-brand, and as little as $2.91 (yeah, really) for the generic equivalent.

Now, I am familiar with the concept of chirality, which turned out to be the reason one particular isomer of one particular drug was safe while another caused birth defects. From an article on Thalidomide:

It was soon discovered that only one particular optical isomer of thalidomide caused the teratogenicity. The pair of enantiomers, while mirror images of each other, cause different effects ...

My question is really about quality control (I understand that the problem in the Thalidomide case wasn't due to poor QA, but a failure to understand how two versions of the same chemical could have such different effects). When a pharmacy sells you a generic pharmaceutical, how can you be sure you're getting something that was manufactured correctly? Is it any agency's job to do QA on these things?

  • 4
    The thalidomide disaster couldn't have been prevented even if they has used stereochemically pure thalidomide (only the (R) enantiomer), as thalidomide racemizes inside the body, it does not matter which one you give as a drug, you always end up with a racemic mixture.
    – Mad Scientist
    Jun 26, 2011 at 15:54
  • define "equivalent". If the packaging says they contain the same amount and combination of active ingredients, the medical effect should be identical (caveat, there might be a difference in absorption of the substances in the body because of different delivery vehicles, but that's not the drug as such and choosing a different delivery vehicle would change that with the brand name drug as well).
    – jwenting
    Jun 27, 2011 at 6:36
  • 2
    But just remember to convince yourself you're taking the brand name pill - since branding can produce a placebo effect than increases the drugs efficacy for some folks!
    – david w
    Jun 28, 2011 at 0:48
  • Are you looking for an answer with regards to the active ingredients or the inactive ingredients as well? As a couple others have pointed out, even though the active ingredients might be the same, the inactive ones might be different enough that they can cause problems for people with allergies or the mechanical delivery might be different enough to affect a minority of users.
    – rjzii
    Jun 21, 2013 at 13:20
  • @rob: I meant the whole package. It's one thing to have the same active ingredients, but if that includes binders that may cause problems, or anything else that would render the generics as less than the name brand in any way.
    – Robusto
    Jun 21, 2013 at 15:28

3 Answers 3


Yes, in the United States it is the job of the FDA, to check that the medicine contains what the manufacturer claims also with generic drugs. As per their "Generic Drugs: Questions and Answers":

What standards do generic drugs have to meet?

Health professionals and consumers can be assured that FDA approved generic drugs have met the same rigid standards as the innovator drug. To gain FDA approval, a generic drug must:

  • contain the same active ingredients as the innovator drug (inactive ingredients may vary)
  • be identical in strength, dosage form, and route of administration
  • have the same use indications
  • be bioequivalent
  • meet the same batch requirements for identity, strength, purity, and quality
  • be manufactured under the same strict standards of FDA's good manufacturing practice regulations required for innovator products

Further Reading (for US):

  • 5
    +1 It's called bioequivalence, and must be shown statistically by pre-clinical (animal) and clinical (people) trials. That's not to say there aren't problems sometimes. Jun 26, 2011 at 16:32
  • 1
    @Robusto: Anecdotally, I know of a woman who blames the suicide of her son on the fact that he was taking a generic version of a psychotropic drug. It's possible for the formulation (the binder) or the manufacturing process to be different enough that it passes official bioequilavence but may have a significantly different absorption or clearance rate depending on covariates such as concomitant medications, foods, demographic factors, or disease states. It can be more distasteful therefore poorer compliance. It's not a perfect science. Jun 26, 2011 at 17:05
  • 1
    @Robusto: In case you didn't guess, I make software for that business. Jun 26, 2011 at 17:30
  • 1
    Note that there is no general reason to believe that the "significantly different absorption or clearance rate" of generic drugs is consistently negative, for all medicines in all cases. I.e. they may very well work better than the "official" medicine. Medical reality is not a slave to legal concepts such as patents.
    – MSalters
    Jun 28, 2011 at 13:10
  • 2
    @slim chemically equivalent drugs are not necessarily mechanically identical. For example different coatings on a pill can change the release rate in the body, and with it the effectiveness or duration of effectiveness of the drug in the patient.
    – jwenting
    Jun 21, 2013 at 12:28

Yes and no. As Lennart said, the FDA verifies that generic drugs have the same ACTIVE ingredients in the same amounts as name-brand drugs are. So for most of us, the answer is a simple "yes."

However, if you have problems with certain common ingredients, like those with celiac disease, the filler (excipients), or INACTIVE ingredients can be problematic. A lot of drug fillers contain gluten, which will damage the intestinal lining of anyone with celiac disease. Name-brand drug manufacturers can generally tell you whether any of their fillers contain a certain ingredient (such as gluten) if you call their customer service (my wife has to do this for her clients periodically). In prescriptions, where only active ingredients are generally listed, generic manufacturers use whatever fillers are cheapest at a given moment, so a generic drug made this week might have different inactive ingredients than the same pharmacy's generic brand of the same drug made last week or the week before (according to some of the manufacturers when called by medical professionals asking on behalf of their clients). None of the labeling requirements for food with respect to common allergens apply to drugs. (Celiac is not an allergy, but since wheat is a common allergen, those with celiac benefit from the food labeling requirements). With non-prescription drugs, where inactive ingredients are listed, you should be able to scour through the label and find out if its ingredients will be problematic, but you'll need to read the label, since, as your question asks, the generics are not "really equivalent" to name-brand drugs in terms of their inactive ingredients.

I suspect the same is true for some other conditions, but the amount of inactive ingredient in your typical drug is unlikely to be enough to be a problem for people with food sensitivities or allergies. A person would need to have a condition that makes them sensitive to very small amounts of an ingredient (or take a very large quantity of a given drug) for this to be an issue. Again, to emphasize the point, for the vast majority of us, this is not a problem, and we only need to be concerned about the active ingredients, which ARE equivalent between generic and name-brand drugs.

A few points of reference:

  • The Food Allergen Labeling and Consumer Protection Act of 2004 provides some help to those with Celiac by requiring foods containing wheat products to be clearly labeled (unless a food contains barley or rye, which aren't wheat but contain the type of gluten that celiacs must avoid), but drugs are not included in this regulation.
  • A 2007 article from the journal Practical Gastroenterology titled Medications and Celiac Disease—Tips From a Pharmacist discusses the challenges celiac patients have with drugs. One key quote related to the response above: "The drug manufacturers must utilize only FDA approved excipients, but the quantity and type of excipient is not specifically regulated. This is important to understand, especially in the manufacturing of generic drug products, since generic product does not have to contain the same excipients as the brand name product. The generic drug manufacturers must demonstrate certain absorption characteristics when they reproduce a drug, but all other aspects can differ."
  • Last year, my wife presented at an FDA hearing on the Development of Articles for Rare Diseases on behalf of the Celiac Sprue Association to make a case for celiac-friendly labeling on drugs. If you can load the morning presentation (it seems to promt for a login, but offer no way of registering), the relevant material starts at about 2h14m into the recording.
  • The National Center for Celiac Awareness's article, Gluten in Medications for Patients goes over some of these same issues.
  • 4
    Erik, please do some research and provide references for your answer. References are not optional on Skeptics.
    – Sklivvz
    Jun 27, 2011 at 6:33
  • 1
    even "generic" drugs require certification before they can be sold and that includes having a constant recipe. Unless you're talking about stuff like vitamin pills and "food supplements" where there's indeed a lot of quackery, but those aren't medicine.
    – jwenting
    Jun 27, 2011 at 6:34
  • Since comments are limited to so few characters, I'll add to my response rather than leaving a detailed response here. jwenting - take a look at a nearby prescription bottle. It'll generally list the active ingredient(s) and nothing else. Weigh the pill, and you'll see that its mass exceeds the listed ingredient (that 35mg dosage pill has more than 35mg of mass). Non-prescription drugs have more comprehensive labeling, but their requirements are still less strict than food labeling requirements. Jun 27, 2011 at 21:55
  • @jwenting: its not about consistency, it is about knowing for sure. Name brands often have a readily-accessible phone number and a post office address where a consumer (not a regulator) can write to ask.
    – horatio
    Aug 26, 2011 at 17:44
  • It's worth mentioning that "fillers" are an important part of ensuring that you get a consistent dosage of the drug and that the brand name medicines may be no better than the generics in terms of which fillers are used. Oct 7, 2014 at 12:58

Yes, generic drugs are equivalent to brand name drugs. All chemical constituents of generic drugs are same as brand drugs. Only the manufacturer company is different.

FDA - Understanding Generic Drugs

Generic Drugs vs Branded Drugs

A generic drug is a drug that is similar to a branded drug but uses a different name. The United States Food and Drug Administration (FDA) contemplates that a generic drug is similar to a branded or pioneer drug in quality, intended use, mode of administration and strength. Generic drugs are usually less expensive compared to branded drugs. The cost of branded drugs is very high and most people tend to buy generic drugs due to their low cost. Both the generic and branded drugs are bio-equivalent meaning they are chemically the same.

  • 2
    Second link looks a bit suspicious, the site doesn't come off as something I would use as a secure source. Can you also quote the relevant parts from the sites?
    – Wertilq
    Jun 21, 2013 at 9:05
  • Put the quote in the answer, not in the comments. There is a button to turn text into quote.
    – Wertilq
    Jun 21, 2013 at 11:33
  • seems like a site making its money selling off brand drugs. Of course they'd claim they were identical or even superior to brand name drugs. The FDA statement means nothing, as many off brand drugs (especially those sold on the black market and over the internet) are not bio-equivalent but contain different carriers and packaging, changing their reaction in the body.
    – jwenting
    Jun 21, 2013 at 12:31

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