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From: trigonometry1972 on 24 Jun 2008 23:11 While I am no big fan of the PPI meds long term, they still should have limited use in medicine, IMO. This indicates the PPI meds will in time all receive the Prilosec to Nexium type improvement. 1: World J Gastroenterol. 2008 Apr 28;14(16):2617-9. Is the required therapeutic effect always achieved by racemic switch of proton-pump inhibitors? Zhou Q, Yan XF, Pan WS, Zeng S. Department of Clinical Pharmacy, The 2nd Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang 310009, China. zhouquan142602(a)zju.edu.cn. Many of the drugs currently used in medical practice are racemates. The enantiomers of a racemic drug differ in pharmacodynamics and/or pharmacokinetics, thus in some cases it is preferable to develop pure enantiomers by racemic switch. In a recent study by Pai et al, dexrabeprazole [R(+)-rabeprazole] (10 mg) was found to be more effective than rabeprazole (20 mg) in the treatment of gastroesophageal reflux disease. We read with great interest in this study and discussed whether such racemic switch would be applicable to other proton-pump inhibitors (PPIs). A literature review indicates that stereoselective pharmacokinetics, rather than stereoselective pharmacological activity, is the main cause of differences in clinical efficacy between pure enantiomer and racemic PPI. Racemic switches of PPI provide the therapeutic advantages such as reducing metabolic load on the body, simplifying pharmacokinetics, providing benefit to the non-responders to standard dose of racemate, more homogenous response to treatment and better efficacy with equal safety. Further studies in quantitative structure-activity relationships (QSARs) are needed to address the fact that the preferred enantiomer of PPI is not always in the same absolute configuration, i.e. S-form is for omeprazole, pantoprazole and tenatoprazole whereas R-form is for lansoprazole and rabeprazole. PMID: 18442220 |