Pharmacokinetics ethnic factors

EU CPMP (1999) Note for Guidance on Modified Release Oral and Transdermal Dosage Forms Section II (Pharmacokinetic and Clinical Evaluation) July 1999 EU CPMP (2001) Note for Guidance on the Investigation of Bioavailability and Bioequivalence. July 2001 ICH-E5 (1998) Ethnic Factors in the Acceptability of Foreign Clinical Data. March 1998... 

Ethnic differences have been shown to influence response to psychotropic medications. Much of the focus on the explanation for such differences has been on drug-metabolizing (CYP) enzymes of the liver and their sway over pharmacokinetic factors. It is now well recognized that differences in the distribution of polymorphic variants of CYP enzymes exist between different ethnic groups. However, within ethnic groups there are considerable inter-individual variations in drug kinetics, which may not be accounted for solely by genetic variation. Responses to pharmacotherapy are multifaceted and involve the interaction of environmental and... 

It is widely held that differences exist in the usage and dosage of antipsychotics among ethnic minority groups. A number of factors are felt to account for these differences and include sociocultural variables (racial bias, cultural divide between patient and physician, language), as well as biological variables (pharmacogenetic, pharmacokinetic, and pharmacodynamic). 

As shown in Figure 15.1, variations in the ethnic response to drugs are related to many interlinking factors. Genetic factors that control both pharmacokinetics and... 

The mechanisms underlying ethnic/cultural differences in pharmacokinetics and pharmacodynamics are not always clear and warrant considerably more study. Such group differences do remind us, however, that nonpharmacological factors may influence the drug experience at any point along the steps" listed in Table 4.1. 

As mentioned in two critical reviews on transcultural psychopharmacology of the TCAs (Pi et al. 1993a Sramek and Pi 1999), the concept of differences between Asian and non-Asian populations in the pharmacokinetics and pharmacodynamics of TCAs has gained support from clinical reports and controlled studies. Whether these differences are due to ethnicity, pharmacokinetics, pharmacodynamics, environmental factors, or shortcomings of study design (such as small sample size) is not definitely known. Although recent studies of CYP polymorphism support the possibility of genetic differences, future studies will need to address these issues. 

In the fifth and final chapter, Drs. Roy V. Varner and Pedro Ruiz and David R. Small, M.B.A., address the need for investigational studies focusing on pharmacokinetic, pharmacodynamic, and pharmacogenetic factors in the public psychiatric sector. After all, it is in the public sector that most of the ethnic or cultural minority groups in the United States receive their psychiatric care. Also reviewed are the results of several studies of responses to antidepressants and neuroleptics by multiethnic populations treated in the public sector. 

Susceptibility factors In a review of available studies, there was no effect of sex, ethnic origin (white, black, Asian, and Hispanic patients), or age on the pharmacokinetics of liraglutide. Data on patients above and below the age of 65 years suggest similar pharmacokinetics, although information in those aged over 75 years is limited [55 ]. 

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