Editing Omeprazole (section)

==== Chirality ====
The two different chiralities of omeprazole are both metabolized into inactive products by [[cytochrome P450]] enzymes, but each chirality are differently inactivated by specific isozymes. Compared to the (''R'')-enantiomer, the (''S'')-enantiomer is relatively more resistant to metabolism, especially metabolism by [[CYP2C19]]<ref>{{cite journal | vauthors = Roche VF | title = The chemically elegant proton pump inhibitors | journal = American Journal of Pharmaceutical Education | volume = 70 | issue = 5 | pages = 101 | date = October 2006 | pmid = 17149430 | doi = 10.5688/aj7005101 | pmc = 1637016 }}</ref> (if it's processed by CYP2C19 at all).<ref>{{cite journal | vauthors = Shiohira H, Yasui-Furukori N, Yamada S, Tateishi T, Akamine Y, Uno T | title = Hydroxylation of R(+)- and S(-)-omeprazole after racemic dosing are different among the CYP2C19 genotypes | journal = Pharmaceutical Research | volume = 29 | issue = 8 | pages = 2310–2316 | date = August 2012 | pmid = 22549736 | doi = 10.1007/s11095-012-0757-x }}</ref> As a result, among people with a more active version of CYP2C19 ("extensive metabolizers"), the (''R'') half of a dose of omeprazole is likely to perform more poorly. Conversely, among those with a less active version of CYP2C19 ("poor metabolizers"), more the (''R'') half is expected to survive metabolism and end up useful. The proportion of the poor metabolizer [[phenotype]] varies widely between populations, from 2.0 to 2.5% in African Americans and white Americans to >20% in Asians. Several [[pharmacogenomics]] studies have suggested that PPI treatment should be [[personalized medicine|tailored]] according to CYP2C19 metabolism status.<ref>{{cite journal | vauthors = Furuta T, Shirai N, Sugimoto M, Nakamura A, Hishida A, Ishizaki T | title = Influence of CYP2C19 pharmacogenetic polymorphism on proton pump inhibitor-based therapies | journal = Drug Metabolism and Pharmacokinetics | volume = 20 | issue = 3 | pages = 153–167 | date = June 2005 | pmid = 15988117 | doi = 10.2133/dmpk.20.153 | s2cid = 19090952 }}</ref>

[[AstraZeneca]] also [[drug development|developed]] [[esomeprazole]] (Nexium) which is a [[eutomer]], purely the (''S'')-enantiomer, rather than a racemate like omeprazole.<ref name="www1.astrazeneca-us.com"/>