Search Results (4)

Cytochrome P450 (CYP450) enzymes are pivotal in the metabolism of numerous anticancer agents, with CYP3A4 being the predominant isoform involved. Inhibition of CYP450 enzymes is a major mechanism underlying clinically significant drug-drug interactions (DDIs), particularly in oncology, where polypharmacy is frequent. This review aims to provide a comprehensive and critical overview of CYP450 enzyme inhibition, focusing specifically on the impact of kinase inhibitors (KIs) and poly adenosine diphosphate-ribose polymerase (PARP) inhibitors. A systematic review of the current literature was conducted, focusing on the molecular mechanisms of CYP450 inhibition, including reversible, time-dependent, mechanism-based, and pseudo-irreversible inhibition. Specific attention was given to the inhibitory profiles of clinically relevant KIs and PARP inhibitors, with analysis of pharmacokinetic consequences and regulatory considerations. Many KIs, such as abemaciclib and ibrutinib, demonstrate time-dependent or quasi-irreversible inhibition of CYP3A4, while PARP inhibitors like olaparib and rucaparib exhibit moderate reversible and time-dependent CYP3A4 inhibition. These inhibitory activities can significantly alter the pharmacokinetics of co-administered drugs, leading to increased risk of toxicity or therapeutic failure. Regulatory guidelines now recommend early identification of time-dependent and mechanism-based inhibition using physiologically based pharmacokinetic) (PBPK) modeling. CYP450 inhibition by KIs and PARP inhibitors represents a critical but often underappreciated challenge in oncology pharmacotherapy. Understanding the mechanistic basis of these interactions is essential for optimizing treatment regimens, improving patient safety, and supporting personalized oncology care. Greater clinical vigilance and the integration of predictive modeling tools are necessary to mitigate the risks associated with CYP-mediated DDIs. Full article

Addiction is a complex psychosocial problem that has significant psychosocial effects on family members. The aim of this study is to gain insight into the burden and psychological distress suffered by caregivers of drug abusers. Ninety-nine caregivers of hard drug addicts participated in this study. The test group consisted of 50 participants and the control group had 49 participants. The participants filled out the General Demographic Questionnaire; Caregiving and the Experience of Subjective and Objective Burden; SCL-90-R; and WHOQOL-BREF. Caregivers of addicts who were preparing to join the community exhibited a significantly higher objective burden, subjective burden, subjective stress burden and greater psychological distress in comparison to caregivers of addicts in the community, and their quality of life was poorer (p < 0.001). The following showed to be risk factors for psychological distress: families with a greater number of children, marital, employment and economic status and duration of addiction. The protective factors were better quality of life, long-term marriage and higher education level of caregivers. Caring for addicts who are living with their families is a significant responsibility and burden for caregivers. Full article

Acacetin, apigenin, chrysin, and pinocembrin are flavonoid aglycones found in foods such as parsley, honey, celery, and chamomile tea. Flavonoids can act as substrates and inhibitors of the CYP3A4 enzyme, a heme containing enzyme responsible for the metabolism of one third of drugs on the market. The aim of this study was to investigate the inhibitory effect of selected flavonoids on the CYP3A4 enzyme, the kinetics of inhibition, the possible covalent binding of the inhibitor to the enzyme, and whether flavonoids can act as pseudo-irreversible inhibitors. For the determination of inhibition kinetics, nifedipine oxidation was used as a marker reaction. A hemochromopyridine test was used to assess the possible covalent binding to the heme, and incubation with dialysis was used in order to assess the reversibility of the inhibition. All the tested flavonoids inhibited the CYP3A4 enzyme activity. Chrysin was the most potent inhibitor: IC₅₀ = 2.5 ± 0.6 µM, K_i = 2.4 ± 1.0 µM, k_inact = 0.07 ± 0.01 min⁻¹, k_inact/K_i = 0.03 min⁻¹ µM⁻¹. Chrysin caused the highest reduction of heme (94.5 ± 0.5% residual concentration). None of the tested flavonoids showed pseudo-irreversible inhibition. Although the inactivation of the CYP3A4 enzyme is caused by interaction with heme, inhibitor-heme adducts could not be trapped. These results indicate that flavonoids have the potential to inhibit the CYP3A4 enzyme and interact with other drugs and medications. However, possible food–drug interactions have to be assessed clinically. Full article

Prostanoids are lipid compounds that mediate a variety of physiological and pathological functions in almost all body tissues and organs. Thromboxane (TX) A₂ is a powerful inducer of platelet aggregation and vasoconstriction and it has ulcerogenic activity in the gastrointestinal tract. Overdose or chronic use of a high dose of acetaminophen (N-acetyl-paminophenol, APAP) is a major cause of acute liver failure in the Western world. We investigated whether TXA₂ plays a role in host response to toxic effect of APAP. CBA/H Zg mice of both sexes were intoxicated with a single lethal or high sublethal dose of APAP, which was administered to animals by oral gavage. The toxicity of APAP was determined by observing the survival of mice during 48 h, by measuring concentration of alanine-aminotransferase (ALT) in plasma 20–22 h after APAP administration and by liver histology. The results have shown that anti-thromboxane (TX) B₂ antibodies (anti-TXB₂) and a selective inhibitor of thromboxane (TX) synthase, benzylimidazole (BZI), were significantly hepatoprotective, while a selective thromboxane receptor (TPR) antagonist, daltroban, was slightly protective in this model of acute liver injury. A stabile metabolite of TXA₂, TXB₂, and a stabile agonist of TPR, U-46619, had no influence on APAP-induced liver damage. Our findings suggest that TXA₂ has a pathogenic role in acute liver toxicity induced with APAP, which was highly abrogated by administration of anti-TXB₂. According to our results, this protection is mediated, at least in part, through decreased production of TXB₂ by liver fragments ex vivo. Full article