Nexium

[kwakster928]

I just learned from class today that Nexium (esomeprazole) is a separated enantiomer of Prilosec (omeprazole). but it puzzles me because 1. i can't find a chrial carbon in omeprazole. you guys have any idea what the real chemical structure of esomeprazole?

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[TrojanAnteater]

S, R-Omeprazole

S= Nexium
R= Prilosec

Journal article from which I found it
http://dmd.aspetjournals.org/cgi/reprint/28/8/966

 

[kwakster928]

thanks a lot. I totally forgot about the sulfur. that makes more sense.

 

[ZpackSux]

S, R-Omeprazole

S= Nexium
R= Prilosec

Journal article from which I found it
http://dmd.aspetjournals.org/cgi/reprint/28/8/966

Go SC

 

[kwakster928]

that was by far the best reponse i have ever gotten. complete and thorough.

 

[ZpackSux]

that was by far the best reponse i have ever gotten. complete and thorough.

Go SC!

By the way.. talking about R and S enantiomers.. What do you think about Albuterol inhalation vs Xopenex inhalation?

 

[TrojanAnteater]

that was by far the best reponse i have ever gotten. complete and thorough.

I actually learned something before pharmacy school. It was a fun little research assignment.

 

[dgroulx]

Go SC!

By the way.. talking about R and S enantiomers.. What do you think about Albuterol inhalation vs Xopenex inhalation?

Go with the albuterol. Xopenex isn't any more effective, just more expensive.

 

[Glycerin]

What do you think about Albuterol inhalation vs Xopenex inhalation?

I know the pharmacists where I work don't like when the docs write for Xopenex over albuterol. It's non-formulary and WAY more expensive.

 

[ZpackSux]

I know the pharmacists where I work don't like when the docs write for Xopenex over albuterol. It's non-formulary and WAY more expensive.

What's the difference between Xopenex and albuterol? I'm testing y'all.

But I will tell u that Xopenex costs 20X more than albuterol UD inhalant.

 

[Glycerin]

What's the difference between Xopenex and albuterol? I'm testing y'all.

I dunno. I'm not in skool yet. Levalbuterol is the R-enantiomer of albuterol, though (I looked it up).

 

[WVUPharm2007]

S, R-Omeprazole

S= Nexium
R= Prilosec

Journal article from which I found it
http://dmd.aspetjournals.org/cgi/reprint/28/8/966

Prilosec is actually the racemic mixture of R&S isomers while Nexium is an isolate of just the S isomer. The S isomer is the one with greater potency at the H+/K+ ATPase pump, so for all intents and purposes the R isomer is far less useful. I think it may have some affinity for the receptor whereever it binds on the pump, but not as much as the S isomer by a long shot.

random googled references about such drugs:
http://www.medletter.com/freedocs/prilosec.pdf
http://www.ti.ubc.ca/pages/letter45.htm

The kicker is that the clinical trials put Nexium 20 and 40 against prilosec 20. So that means you have 20mg S isomer (Nexium) vs. 10mg S isomer (Prilosec) in one instance and 40mg S isomer (Nexium) vs. 10mg S isomer (Nexium) in another instance. From the start, Prilosec has 50-75% less active ingredient than Nexium; it's no wonder it showed more efficacy in many patients.

It makes me want to kick AstraZeneca square in the nuts.

 

[Sosumi]

What's the difference between Xopenex and albuterol? I'm testing y'all.

But I will tell u that Xopenex costs 20X more than albuterol UD inhalant.

Isn't Xopenex (Levalbuterol) just the (R)-entaniomer of albuterol which is a racemate? Thus the R enantiomer is supposedly more potent in bronchodilation having something to do with more affinity of Beta-2 receptors (somewhere in notes in pharmacology last year). There's controversy in overall clinical efficacy of Xopenex versus good old albuterol to justify that high cost. Do any insurance companies actually have it on their formulary?

 

[WVUPharm2007]

Do any insurance companies actually have it on their formulary?

Depends on the stupidity of said insurance company.

 

[ZpackSux]

Isn't Xopenex (Levalbuterol) just the (R)-entaniomer of albuterol which is a racemate? Thus the R enantiomer is supposedly more potent in bronchodilation having something to do with more affinity of Beta-2 receptors (somewhere in notes in pharmacology last year). There's controversy in overall clinical efficacy of Xopenex versus good old albuterol to justify that high cost. Do any insurance companies actually have it on their formulary?

If Xopenex is the R-enantiomer, then what is Albuterol?

 

[bananaface]

If Xopenex is the R-enantiomer, then what is Albuterol?

Albuterol is the racemate, as stated above.

http://www.fda.gov/cder/foi/label/2002/20837S6lbl.pdf
see lines 10-12

There can be some benefit to having single enantiomer formulations if the enantiomer not selected for inclusion causes the same side effects but has lesser desired activty, when the enantiomer not selected has side effects not seen with the selected enantiomer, when the enantiomer not selected has interactions that the selected enantiomer does not, and so forth. I'm not saying that single enantiomer drugs are inherently better than the racemic mixture. And, certainly companies do pursue these with patent retention as a primary motive. I'm just pointing out that single enantiomer drugs can be better than the racemate in some cases.

 

[ZpackSux]

OK... so Racemic Albuterol contains 1.25mg of R-Albuterol and 1.25mg of S-Albuterol. And Xopenex is 1.25mg R-Albuterol.. or 0.63mg...

Then R-Albuterol is the active molecule.. and S-Albuterol is not. But S-Albuterol contributes to increasing ADR?

 

[ZpackSux]

Surprise...

Look at the page 15 .. Looks like Xopenex has just as much or more adverse drug reaction compared to Albuterol.. dose per dose.. xopenex 1.25mg = albuterol 2.5mg

http://www.fda.gov/cder/foi/label/2002/20837S6lbl.pdf

Heck.. it costs 20 times more.. better provide..more (inclucing the ADR) than the good ole bad albuerol..

 

[DanMatan]

This is mostly off-topic, but while we're talking about Nexium and Prilosec, I was wondering about the COX-2 specific NSAIDs that were taken off/soon to be taken off the market (Bextra, Celebrex, etc.). Since the advantage of these drugs is that they don't have the stomach-acid inducing side effects of non-specific NSAIDs (ASA, etc), couldn't one take the non-specific NSAIDs with Nexium/Prilosec and avoid the stomach acid problems and achieve the exact same effect?

Or is the stomach acid caused by the non-specific NSAIDs not stoppable via Prilosec/Nexium etc?

 

[ultracet]

This is mostly off-topic, but while we're talking about Nexium and Prilosec, I was wondering about the COX-2 specific NSAIDs that were taken off/soon to be taken off the market (Bextra, Celebrex, etc.). Since the advantage of these drugs is that they don't have the stomach-acid inducing side effects of non-specific NSAIDs (ASA, etc), couldn't one take the non-specific NSAIDs with Nexium/Prilosec and avoid the stomach acid problems and achieve the exact same effect?

Or is the stomach acid caused by the non-specific NSAIDs not stoppable via Prilosec/Nexium etc?

On this note... I honestly would recommend enteric coating for ASA, naproxen, ibuprofen, etc.

I don't know why you wouldn't use that instead of the regular tabs except in the instance of MI

 

[Sosumi]

On this note... I honestly would recommend enteric coating for ASA, naproxen, ibuprofen, etc.

I don't know why you wouldn't use that instead of the regular tabs except in the instance of MI

Doesn't enteric coating decrease dissolution and absorption rate? -- not good for when you want quick and immediate pain relief.

 

[Scientist]

On this note... I honestly would recommend enteric coating for ASA, naproxen, ibuprofen, etc.

I don't know why you wouldn't use that instead of the regular tabs except in the instance of MI

Don’t quote me on this but I think once the tablet disintegrates, it does not matter if it’s enteric coated because the COX –1 will inhibit the prostaglandins needed to protect the GI mucosa. All steroidals? are Cox-2 inhibitors and Cox-2 inhibitors do have some Cox1-I effects…..but is minimal. What you need is a low risk drug (meaning inhibits cox 2 more that cox 1). ASA, IBU, and Naproxen all are medium risk (inhibit both Cox 1 and 2 about the same).

Good examples of low risk meds are: etodolac LODINE, nabumetone RELAFEN, sulindac CLINORIL

 

[Scientist]

This is mostly off-topic, but while we're talking about Nexium and Prilosec, I was wondering about the COX-2 specific NSAIDs that were taken off/soon to be taken off the market (Bextra, Celebrex, etc.). Since the advantage of these drugs is that they don't have the stomach-acid inducing side effects of non-specific NSAIDs (ASA, etc), couldn't one take the non-specific NSAIDs with Nexium/Prilosec and avoid the stomach acid problems and achieve the exact same effect?

Or is the stomach acid caused by the non-specific NSAIDs not stoppable via Prilosec/Nexium etc?

DanMatan, one of the treatments for NSAIDS induced dyspepsia is a proton-pump inhibitors like Prilosec and Prevacid. There’s a combo drug (ARTHROTEC, diclofenac & misoprostol) on the market that was made less appealing when the Cox-2 inhibiting drugs came into sale. Plus, the price of this combo drug was more than the Cox2-I. It will probably become more popular now.

 

[dgroulx]

This is mostly off-topic, but while we're talking about Nexium and Prilosec, I was wondering about the COX-2 specific NSAIDs that were taken off/soon to be taken off the market (Bextra, Celebrex, etc.). Since the advantage of these drugs is that they don't have the stomach-acid inducing side effects of non-specific NSAIDs (ASA, etc), couldn't one take the non-specific NSAIDs with Nexium/Prilosec and avoid the stomach acid problems and achieve the exact same effect?

Or is the stomach acid caused by the non-specific NSAIDs not stoppable via Prilosec/Nexium etc?

There are NSAIDS compounded this way, like Arthrotec.

Also, many people who were taking Celebrex for their arthritis were also taking an aspirin a day for their platelets. It totally defeated the purpose.

 

[Sosumi]

Don’t quote me on this but I think once the tablet disintegrates, it does not matter if it’s enteric coated because the COX –1 will inhibit the prostaglandins needed to protect the GI mucosa. All steroidals? are Cox-2 inhibitors and Cox-2 inhibitors do have some Cox1-I effects…..but is minimal. What you need is a low risk drug (meaning inhibits cox 2 more that cox 1). ASA, IBU, and Naproxen all are medium risk (inhibit both Cox 1 and 2 about the same).

Good examples of low risk meds are: etodolac LODINE, nabumetone RELAFEN, sulindac CLINORIL

None of those drugs are very selective for Cox-2. Some of your "low risk meds" claim to be more selective but aren't really. Their main advantage is their long duration of action. I haven't really seen an studies that believably show reduced GI toxicity risk. Cox-2's didn't really lower GI risk that much neither. Some of the data was suppressed showing the decrease was much lower than previously believed.

That said, I'm a big fan of Celebrex. My mom and aunts can't take aspirin and love ibuprofen but can't take too much of it. Only Celebrex seemed to work for them.

 

[kwakster928]

None of those drugs are very selective for Cox-2. Some of your "low risk meds" claim to be more selective but aren't really. Their main advantage is their long duration of action. I haven't really seen an studies that believably show reduced GI toxicity risk. Cox-2's didn't really lower GI risk that much neither. Some of the data was suppressed showing the decrease was much lower than previously believed.

That said, I'm a big fan of Celebrex. My mom and aunts can't take aspirin and love ibuprofen but can't take too much of it. Only Celebrex seemed to work for them.

I was believed to be that COX2 are responsible for postaglandin sysnthesis that is responsible for imflammation, pain and fever, while COX1 are belived to be resposible for prostagliandins that increase gastic mucus secretion. they thought that just blocking COX2 will minimize GI side effects i think they are working until this whole vioxx issue came to market. i dont know about any drugs being safe to the extent. it is very very lousy statement i think.

 

[neonam11]

This is mostly off-topic, but while we're talking about Nexium and Prilosec, I was wondering about the COX-2 specific NSAIDs that were taken off/soon to be taken off the market (Bextra, Celebrex, etc.). Since the advantage of these drugs is that they don't have the stomach-acid inducing side effects of non-specific NSAIDs (ASA, etc), couldn't one take the non-specific NSAIDs with Nexium/Prilosec and avoid the stomach acid problems and achieve the exact same effect?

Or is the stomach acid caused by the non-specific NSAIDs not stoppable via Prilosec/Nexium etc?

I think that some physicians do prescribe a combo of NSAID and proton pump inhibitor like Nexium or Prilosic (at least more so before the COXII came along) for patients prone to developing GI bleeding. I think the COXII wanted bragging rights because you only have to take one tablet, not two. Also, some MDs have also used Misoprostol (PGE analogue) to prevent NSAID induced ulcers.