Posted by ed_uk2010 on July 31, 2010, at 10:01:04
In reply to Re: Fillers in meds, why not the same? Generics, posted by bleauberry on July 30, 2010, at 19:04:58
> Well, the active ingredient is theoretically the same, but no one has proven it to be clinically the same.
I'm not sure what you mean here. Sertraline hydrochloride, for example, is sertraline hydrochloride. Generic sertraline tablets do not contain a different 'type' of sertraline to Zoloft. It is the same chemical entity.
>Assuming exact same ingredient....generics only have to be within a certain percentage of brand. If one pill is 6% short, and the other 6% over, guess what, you just go a 12% difference in your dose. What if the entire bottle was 10% short?
Generic products must contain the same quantity of drug (active pharmaceutical ingredient) as the brand leader. A generic 50mg sertraline tablet has to contain 50mg of sertraline, for example. It is not permitted to contain 45mg...or 56mg...or 44mg This has to be precise.
It is often claimed that generics can be up to 20% less bio-available or 25% more bio-available than the brand leader. This is not correct. The 0.8 to 1.25 range is part of the complex statistical analysis used to determine bio-equivalence.
In Europe, for example, two medicinal products are considered to be bioequivalent if the 90% confidence intervals of the transformed natural log ratios, between the two preparations, of Cmax and AUC lie in the range 0.80-1.25.>Even plain jane fillers have an influence on the absorption of the ingredient.
Yes, they can do, but whatever excipients are chosen, dissolution tests and bio-availability studies will be performed to assess bio-equivalence.
>...some may help carry it to the brain, some may not.
Excipients used in tablets and capsules do not 'carry' the drug to the brain. Their effect on bioavailability, if any, ends once the API has been absorbed.
>One of my docs won't even prescribe generics.....
That's unusual. I have not come across such a doctor in the UK. I suspect that doctors in the US are more susceptible to the influence of representatives from the major (branded) pharmaceutical companies.
In general, branded prescribing is only necessary for a relatively small proportion of medications. Ciclosporin (Neoral) is a good example; extremely precise blood levels have to be maintained to prevent transplant rejection whilst minimising toxicity. Most commonly used drugs have a wide therapeutic index and at any rate, the bio-availabilities of the various generics may differ little more from each other than between different batches of the branded version itself. This has been demonstrated by the FDA.
poster:ed_uk2010
thread:956143
URL: http://www.dr-bob.org/babble/20100731/msgs/956552.html