Inactivation kinetics and residual activity of CYP3A4 after treatment with erythromycin

Opioid-Related Genetic Polymorphisms of Cytochrome P450 Enzymes after Total Joint Arthroplasty: A Focus on Drug-Drug-Gene Interaction with Commonly Coprescribed Medications

Pharmacogenomic testing, together with the early detection of drug-drug-gene interactions (DDGI) before initiating opioids, can improve the selection of dosage and reduce the risk of adverse drug interactions and therapeutic failures following Total Joint Arthroplasty. The variants of CYP genes can mediate DDGI. Orthopedic surgeons should become familiar with the genetic aspect of opioid use and abuse, as well as the influence of the patient genetic makeup in opioid selection and response, and polymorphic variants in pain modulation.

Sexual Dimorphism in Drug Metabolism and Pharmacokinetics

Background:

Sex and gender-based differences are observed well beyond the sex organs and affect several physiological and biochemical processes involved in the metabolism of drug molecules. It is essential to understand not only the sex and gender-based differences in the metabolism of the drug but also the molecular mechanisms involved in the regulation of drug metabolism for avoiding sex-related adverse effects of drugs in the human.

Method:

The articles on the sex and gender-based differences in the metabolism of drug molecules were retrieved from the Pub Med database. The articles were classified into the metabolism of the drug molecule, gene expression regulation of drug-metabolizing enzymes, the effect of sex hormones on the metabolism of drug, expression of drugmetabolizing enzymes, etc.

Result:

Several drug molecules are known, which are metabolized differently in males and females. These differences in metabolism may be due to the genomic and non-genomic action of sex hormones. Several other drug molecules still require further evaluation at the molecular level regarding the sex and gender-based differences in their metabolism. Attention is also required at the effect of signaling cascades associated with the metabolism of drug molecules.

Conclusion:

Sex and gender-based differences in the metabolism of drugs exist at various levels and it may be due to the genomic and non-genomic action of sex hormones. Detailed understanding of the effect of sex and related condition on the metabolism of drug molecules will help clinicians to determine the effective therapeutic doses of drugs dependingon the condition of patient and disease.

Inhibitory kinetics of fruit components on CYP2C19 activity

It has been suggested that the fruit components resveratrol (RSV), 6', 7'-dihydroxybergamottin (DHB), and bergamottin (BG) might inhibit cytochrome P450 2C19 (CYP2C19) activity, but the mode and potency of such inhibition are yet to be investigated. This study aimed to investigate the mode and kinetics of the inhibition of CYP2C19-based omeprazole metabolism by RSV or grapefruit juice components (DHB or BG). RSV and DHB reduced CYP2C19 activity in a preincubation time-dependent manner, suggesting that they inactivated CYP2C19 via mechanism-based inhibition (MBI). Although BG inactivated CYP2C19 in a preincubation time- and concentration-dependent manner, suggesting that both MBI and reversible inhibition contributed to these effects, the concentration required to achieve 50% inhibition was 26-fold higher for reversible inhibition than for MBI (0.859 and 0.0331 μM, respectively), indicating that the inhibition of CYP2C19 by BG is primarily attributable to MBI. Based on the estimated intestinal concentrations of these components, it is considered that >90% of CYP2C19 would be inactivated after the consumption of normal amounts of grapefruit juice or RSV-containing substances. In conclusion, these findings suggest that food containing these components has the potential to evoke drug-food interactions caused by the MBI of intestinal CYP2C19 activity in the clinical setting.