Caffeine consumption patterns and determinants among adolescents in Serbia

BACKGROUND

The number of adolescents who use caffeine is constantly increasing. As juvenile age is vulnerable, it is reasonable to expect that they will differently perceive reason and react to caffeine use than adults, and be more prone to unwanted physiological and psychological consequences of its consumption.

AIM

Analysis of the scope and pattern of caffeine consumption among adolescents in Serbia.

STUDY DESIGN

The cross-sectional survey was implemented in the study population of 191 Serbian adolescents during 2010.

RESULTS

The median daily intake of caffeine was 95.6 mg. The major source of caffeine was brewed coffee, and the most common reasons for caffeine intake were leisure, peer influence, or habit. Only 57.6% of the subjects were aware that caffeine is present in consumed beverages. Sex affected the pattern, but not the overall level, of caffeine consumption. No association between caffeine consumption and smoking status, frequency of caffeine use in the family, or negative personal experience with caffeine effects was observed.

CONCLUSION

Our investigation provides first and rather detailed insight into caffeine-containing beverage consumption scope and pattern among Serbian adolescents. For accurate estimation and analysis of caffeine intake in this population, randomized studies with prospective longitudinal design, caffeine content measurement, and more subjects involved are warranted.

The influence of CYP2C8*3 on carbamazepine serum concentration in epileptic pediatric patients

The aim of the present study was to investigate the distribution of CYP2C8 variants *3 and *5, as well as their effect on carbamazepine pharmacokinetic properties, in 40 epileptic pediatric patients on carbamazepine treatment. Genotyping was conducted using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and allele-specific (AS)-PCR methods, and steady-state carbamazepine plasma concentrations were determined by high performance liquid chromatography (HPLC). The CYP2C8 *3 and *5 polymorphisms were found at frequencies of 17.5 and 0.0%, respectively. After dose adjustment, there was a difference in daily dose in CYP2C8*3 carriers compared to non carriers [mean ± standard deviation (SD): 14.19 ± 5.39 vs. 15.46 ± 4.35 mg/kg; p = 0.5]. Dose-normalized serum concentration of carbamazepine was higher in CYP2C8*3 (mean ± SD: 0.54 ± 0.18 vs. 0.43 ± 0.11 mg/mL, p = 0.04), and the observed correlation between weight-adjusted carbamazepine dose and carbamazepine concentration after dose adjustment was significant only in CYP2C8*3 non carriers (r = 0.52, p = 0.002). However, the population pharmacokinetic analysis failed to demonstrate any significant effect of CYP2C8 *3 polymorphism on carbamazepine clearance [CL L/h = 0.215 + 0.0696*SEX+ 0.000183*DD]. The results indicated that the CYP2C8*3 polymorphism might not be of clinical importance for epilepsy treatment in pediatric populations.

CYP1A2 genotype affects carbamazepine pharmacokinetics in children with epilepsy

PURPOSE

The purpose of this study is to investigate the effect of two of the most important functional CYP1A2 variations -3860G > A and -163C > A on carbamazepine pharmacokinetics in Serbian pediatric epileptic patients.

METHODS

The study involved 40 Serbian pediatric epileptic patients on steady-state carbamazepine treatment. Genotyping for -3860G > A and -163C > A was carried out using PCR-RFLP method, and carbamazepine plasma concentrations were determined by high pressure liquid chromatography (HPLC) method. For pharmacokinetic analysis, NONMEM software with implementation of ADVAN 1 subroutine was used.

RESULTS

CYP1A2 polymorphism -163C > A was found at the frequency of 65.0 %, while -3860G > A was not detected. The correlation between weight-adjusted carbamazepine dose and carbamazepine concentration after dose adjustment was significant only in carriers of -163C/C and C/A genotypes (r = 0.68, p = 0.0004). The equation that described population clearance (CL) was CL (l/h) = 0.176 + 0.0484 * SEX + 0.019 * CYP1A2 + 0.000156 * DD, where SEX has a value of 1 if male and 0 if female, CYP1A2 has a value of 1 if -163A/A and 0 if -163C/C or C/A, and DD is the total carbamazepine daily dose (mg/day).

CONCLUSIONS

CYP1A2 -163A/A genotype influence carbamazepine pharmacokinetics. In addition to sex and total carbamazepine daily dose, -163C > A CYP1A2 polymorphism should be considered as a predictor of carbamazepine clearance.