Generic medicines are not always equivalent to the originals
Not a lot of people know that...
You can’t be serious?
I’m not doing a McEnroe on you here!
It is a well known fact among many in the pharmaceutical industry that generic versions of medicines are not always the same as the originally licensed medicine. There are a number of reasons for that (the following is based on US FDA Regulations, but most country or regional regulators are similar).
There are a number of reasons for the differences.
1. The FDA’s definition of bioequivalence is broad
FDA’s definition of bioeqivalence of a generic is surprisingly broad:
A generic’s maximum concentration of active ingredient in the blood must not fall more than 20 percent below or 25 percent above that of the brand name. This means a potential range of 45 percent among generics labeled as being the same.
So, the cheaper alternative does not have to be exactly the same, as people may think.
It does seem a reasonable concession, for a more affordable medicine. to allow some room for manoeuvre. However, this does seem a large margin, and rote acceptance that a generic alternative is as effective as the original may not be in a patient’s best interest.
2. Excipients (non-active ingredients) are not the same
The generic must contain the same active ingredient as the original. But the additional ingredients, known as excipients, can be different and are often of lower quality (the generic company is not allowed to know what excipients the originator used).
Those differences can affect what’s called bioavailability—the amount of drug that could potentially be absorbed into the bloodstream. As the American Heart Association recently noted, ‘Some additives traditionally thought to be inert, such as alcohol sugars, cyclodextrans, and polysorbate-80, may alter a drug’s dissolution, thereby impacting its bioavailability.’ See a paper explaining here.
The FDA standards also do not specifically regulate how quickly the medicine reaches peak concentration in the blood.
That can become a major issue for patients who take generic versions of time-release drugs, which constitute ten percent of the market, according to IMS Health.
The time-release mechanisms for branded drugs are usually protected by separate patents, so generics companies engineer alternative and usually cheaper mechanisms.
That can result in drugs that release active ingredients into the blood far more quickly, leaving patients feeling dizzy or nauseated.
The example here, from a random internet search Two Generic Versions of ADHD Drug Not as Effective: FDA, highlights how two generic versions of a drug were not the same as the original.
3. Manufacturing is not always up to scratch
There is also further evidence from FiercePharma’s web report titled ‘FDA Quietly Testing Some Drugs Generic Equivalency’ https://www.fiercepharma.com/sales-and-marketing/fda-quietly-testing-some-drugs-for-generic-equivalency which reveals:
An independent study of generic versions of Pfizer’s cholesterol-lowering drug “Lipitor” done by Preston Mason at Brigham & Women’s Hospital, found some of the generics were ineffective because of impurities resulting from the manufacturing.