CYP2D6 genotype and debrisoquine metabolic ratio (MR) were analyzed in 133 Nicaraguan Mestizos (NMs) and 260 Cubans divided into Cuban Mestizos (CMs) and White Cubans (WCs). The frequencies of poor metabolizers (MR12.6) were 6% in NMs, 3.9% in CMs and 5.3% in WCs. The frequencies of ultrarapid metabolizers (MR0.1) were 0% in NMs, 2.3% in CMs and 5.3% in WCs. Mean (±s.d.) MR among extensive metabolizers (MR<12.6) was higher in NMs (1.5±1.6; n=118) than in CMs (1.0±1.3; n=124; P<0.001) and WCs (0.7±1.0; n=124; P<0.001). MR correlated with the 'activity score' of CYP2D6 genotypes (P<0.05; r=-0.55). Mean MR was higher among NMs than WCs and CMs for groups classified as 1 (P<0.05) or 2 (P<0.01) 'activity score'. In addition, mean (±s.d.) MR was higher among subjects carrying CYP2D6*17 than in CYP2D6 wt/wt (P<0.001). The CYP2D6*10 allele was higher in NMs (3.1%) than in CMs (0.8%; P<0.05) and WCs (0.4%; P<0.05). CYP2D6*17 allele was higher in CMs (10.2%) than WC (2.7%; P<0.005) and NMs (0%). Thus, the variability in CYP2D6 phenotypes found may be related to differences in allele frequency among groups (that is, CYP2D6*10 and *17 highest in NMs and CMs, respectively). However, the influence of environmental factors or alleles different than those studied here cannot be ruled out.

Corroborating these results further strengthens evidence of the relationship between CYP2D6 metabolic capacity and personality. In this population of healthy Cuban volunteers, the CYP2D6 hydroxylation capacity was related to the degree of anxiety and socialization. These results support the postulated reduction of serotonin in CYP2D6 poor metabolizers, which may be associated with a cluster of behavioral traits (e.g., anxiety, impulsivity). Thus, research is warranted to determine CYP2D6 functional implications for interindividual differences in vulnerability to neuropsychiatric diseases and drug response.

The presence of the -1584G allele in the promoter region of the CYP2D6 gene was related to a high CYP2D6 hydroxylation capacity.

The aims of this study were to evaluate the diclofenac metabolism in Hispanics from Cuba and Spain and its relation to ethnicity, CYP2C9 genotypes and environmental factors. Diclofenac hydroxylation capacity (concentration ratios of diclofenac/metabolites in 8-h urine) was studied in 160 Cuban (classified as 76 Cuban-Whites-CWs and 84 Cuban-Mestizos-CMs) and 148 Spaniard (SPs) healthy volunteers. Diclofenac and its main metabolites, 4'-hydroxy (OH), 3'-OH and 5-OH diclofenac, and CYP2C9*2 to *6 and *8 alleles were also determined in 132 and 128 CWs and CMs, respectively. Gender, tobacco, caffeine and ethanol consumption were also evaluated. The mean diclofenac/4'-OH diclofenac ratio was higher in CMs (0.72±0.25) than in CWs (0.64±0.20; P<0.05) and SPs (0.57±0.26; P<0.001). The mean diclofenac/4'-OH diclofenac ratio was higher (P<0.05) in subjects with CYP2C9*1/*3 (0.77±0.19; n=22) and CYP2C9*1/*8 (0.93±0.33; n=4) genotypes than with CYP2C9*1/*1 (0.65±0.24; n=90). Environmental factors did not seem to influence the diclofenac metabolism in these populations. The present findings show for the first time interethnic differences between Hispanic groups in urinary diclofenac/4'-OH diclofenac ratios, and the relevance of CYP2C9*3 and CYP2C9*8 alleles.