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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 11 of 11. This is the beginning of the thread.
Posted by ed_uk on March 29, 2005, at 16:55:05
Clin Ther. 2003 Jun;25(6):1578-92.
Comment in:
Clin Ther. 2004 May;26(5):801-2.
The bioequivalence and therapeutic efficacy of generic versus brand-name psychoactive drugs.Borgheini G.
Neurological and Psychiatric Department, University of Padua, and Casa di Cura Parco dei Tigli, Padua, Italy. g.borgherini@gpnet.it
BACKGROUND: For the purposes of drug approval, the interchangeability of a generic drug and the corresponding brand-name drug is based on the criterion of "essential similarity," which requires that the generic drug have the same amount and type of active principle, the same route of administration, and the same therapeutic effectiveness as the original drug, as demonstrated by a bioequivalence study. However, bioequivalence and therapeutic effectiveness are not necessarily the same. OBJECTIVE: This review summarizes available data comparing the bioequivalence and therapeutic efficacy of brand-name psychoactive drugs with those of the corresponding generic products. METHODS: Relevant information was identified through searches of MEDLINE, Current Contents/Clinical Medicine, and EMBASE for English-language articles and English abstracts of articles in other languages published between 1975 and the present. The search terms used were generic drug, branded drug, safety, toxicity, adverse events, clinical efficacy, bioequivalence, bioavailability, psychoactive drugs, and excipients. RESULTS: Few publications compared the bioequivalence and efficacy of brand-name and generic psychoactive drugs. Those that were identified revealed differences in the efficacy and tolerability of brand-name and generic psychoactive drugs that had not been noted in the original bioequivalence studies. Specifically, l study found that plasma levels of phenytoin were 31% lower after a switch from a brand-name to a generic product. Several controlled studies of carbamazepine showed a recurrence of convulsions after the shift to a generic formulation. After a sudden recurrence of seizures when generic valproic acid was substituted for the brand-name product, an investigation by the US Food and Drug Administration found a difference in bioavailability between the 2 formulations. Statistically significant differences in pharmacokinetic variables have been reported in favor of brand-name versus generic diazepam (P < 0.001). Finally, a case report involving paroxetine mesylate cast doubt on the tolerability and efficacy of the generic formulation. CONCLUSION: The essential-similarity requirement should be extended to include more rigorous analyses of tolerability and efficacy in actual patients as well as in healthy subjects.
Posted by ed_uk on March 29, 2005, at 17:11:51
In reply to We don't like generics.........., posted by ed_uk on March 29, 2005, at 16:55:05
Biopharm Drug Dispos. 1989 Nov-Dec;10(6):597-605.
Bioinequivalence of a generic brand of diazepam.
Locniskar A, Greenblatt DJ, Harmatz JS, Shader RI.
Department of Psychiatry, Tufts University School of Medicine, Boston, Massachusetts.
Twenty-six healthy male volunteers received a single 10 mg dose of diazepam on two occasions in a crossover bioequivalence study comparing the reference product (Valium) and a generic formulation (NeoCalme). Concentrations of diazepam and its metabolite, desmethyldiazepam, were determined during 264h after each dose. Peak plasma diazepam concentrations were significantly lower for NeoCalme vs Valium (247 vs 394 ng ml-1, p less than 0.001) and reached significantly later after the dose (1.62 vs 0.98 h, p less than 0.001). Total area under the plasma concentration curve (AUC) was also significantly lower for NeoCalme (6614 vs 7552 ng ml-1 x h, p less than 0.001), although AUC ratios for NeoCalme divided by Valium satisfied the '75-75' guidelines. Findings for desmethyldiazepam were similar. Thus, diazepam absorption from the generic brand of diazepam is significantly slower than from Valium, which in turn could lead to therapeutic inequivalence.
Posted by Phillipa on March 29, 2005, at 18:31:03
In reply to A particularly bad generic diazepam............., posted by ed_uk on March 29, 2005, at 17:11:51
Now I know why you have been asking me if I am taking name brand valium in the am. How does mirtazipame compare to remeron? Fondly, Phillipa
Posted by ed_uk on March 29, 2005, at 20:11:02
In reply to Re: A particularly bad generic diazepam............. » ed_uk, posted by Phillipa on March 29, 2005, at 18:31:03
Hi P!
>How does mirtazipame compare to remeron?
I couldn't find any research I'm afraid :-S
Ed xxx
Posted by krybrahaha78 on March 30, 2005, at 18:23:31
In reply to Re: A particularly bad generic diazepam............. » Phillipa, posted by ed_uk on March 29, 2005, at 20:11:02
Mirtazapine is generic Remeron
Posted by ed_uk on March 30, 2005, at 18:33:28
In reply to Re: A particularly bad generic diazepam............., posted by krybrahaha78 on March 30, 2005, at 18:23:31
Hiya!
Phillipa was wondering how generic mirtazapine compares with 'name brand' Remeron. As is the case with diazepam, there may be some differences RE their absorption.
Regards,
Ed.
Posted by yxibow on March 30, 2005, at 23:15:03
In reply to Re: A particularly bad generic diazepam............. » krybrahaha78, posted by ed_uk on March 30, 2005, at 18:33:28
> Hiya!
>
> Phillipa was wondering how generic mirtazapine compares with 'name brand' Remeron. As is the case with diazepam, there may be some differences RE their absorption.
>
> Regards,
> Ed.I didn't notice any particular difference when generic mirtazapine came out. In the US, any medicine generic or not has to be bioequivalent to the order of 80-130%, which is clinically irrelevant for a lot of drugs, but may be relevant for a small subclass of medications. The same "potency" argument can be also applied after all to the original, there's no complete guarantee that name brand is 100% of what it states. (I'm not shilling for any drug companies :) But the absorption argument is probably part of this bioequivalency, generics may use different stearates or other binding elements for their compound.
Posted by paulbwell on March 31, 2005, at 19:09:18
In reply to Re: A particularly bad generic diazepam............. » ed_uk, posted by Phillipa on March 29, 2005, at 18:31:03
Hey,
How do you take your Val?
I always Disolve my good quality, Generic Diazepam, under my tounge, and althought It speeds absorbtion to minutes, I find doing this with IR generic Ritalin, to be VERY noticable. I can feel the medicine start to work within 2-3 minutes this way as opposed to 10-15 for swallowing.
Now i do this with many dissolvable meds.
Posted by Phillipa on April 1, 2005, at 11:11:44
In reply to Phillipa-Valium, posted by paulbwell on March 31, 2005, at 19:09:18
I just swallow the valium with some water. I didn't know you could dissolve valium under the tongue, but I knew xanx you could for a quicker response. Do you think this makes the generic work better? Fondly, Phillipa
Posted by paulbwell on April 3, 2005, at 1:13:34
In reply to Re: Phillipa-Valium, posted by Phillipa on April 1, 2005, at 11:11:44
> I just swallow the valium with some water. I didn't know you could dissolve valium under the tongue, but I knew xanx you could for a quicker response. Do you think this makes the generic work better? Fondly, Phillipa
try it next time. You may be in for a pleasant surprise?. hold it and swish it back and fourth under your tounge, until dissolved.
Valium is very Rapidly taken up into the CNS, before being redistributed, taking much less time to get to the brain, after absorbition from the Tongue membranes. This is Said to be the third most effective method of admin, after:
IV Injection #1
IM-SC Injection #2
and is said to be on a par with 'snorting', with water solidable Meds like Methylphenidate. Benzos (Tablets) are not effective this way or Rectally as suppositories.I do not think It would matter if said tablets were brand name or generic.
Cheers
Posted by paulbwell on April 3, 2005, at 19:32:00
In reply to Re: Phillipa-Valium, posted by paulbwell on April 3, 2005, at 1:13:34
> > I just swallow the valium with some water. I didn't know you could dissolve valium under the tongue, but I knew xanx you could for a quicker response. Do you think this makes the generic work better? Fondly, Phillipa
>
> try it next time. You may be in for a pleasant surprise?. hold it and swish it back and fourth under your tounge, until dissolved.
>
> Valium is very Rapidly taken up into the CNS, before being redistributed, taking much less time to get to the brain, after absorbition from the Tongue membranes. > I do not think It would matter if said tablets were brand name or generic.
>
> CheersActually
IV and smoking of (some) drug matter would compete for #1 quickest onset of drug effect, I think
This is Said to be the third most effective method of admin, after:
> IV Injection #1
> IM-SC Injection #2
> and is said to be on a par with 'snorting', with water solidable Meds like Methylphenidate. Benzos (Tablets) are not effective this way or Rectally as suppositories.
>
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