To elucidate the impact of CYP3A4 activity inhibition and genetic polymorphism on the metabolism of crizotinib. Enzymatic incubation systems for crizotinib were established, and Sprague-Dawley rats were utilized for in vivo experiments. Analytes were quantified using LC-MS/MS. Upon screening 122 drugs and natural compounds, proanthocyanidins emerged as inhibitor of crizotinib metabolism, exhibiting a relative inhibition rate of 93.7%. The IC50 values were 24.53 ± 0.32 μM in rat liver microsomes and 18.24 ± 0.12 μM in human liver microsomes. In vivo studies revealed that proanthocyanidins markedly affected the pharmacokinetic parameters of crizotinib. Co-administration led to a significant reduction in the AUC(0-t), Cmax of PF-06260182 (the primary metabolite of crizotinib), and the urinary metabolic ratio. This interaction is attributed to the mixed-type inhibition of liver microsome activity by proanthocyanidins. CYP3A4, being the principal metabolic enzyme for crizotinib, has its genetic polymorphisms significantly influencing crizotinib\'s pharmacokinetics. Kinetic data showed that the relative metabolic rates of crizotinib across 26 CYP3A4 variants ranged from 13.14% (CYP3A4.12, 13) to 188.57% (CYP3A4.33) when compared to the wild-type CYP3A4.1. Additionally, the inhibitory effects of proanthocyanidins varied between CYP3A4.12 and CYP3A4.33, when compared to the wild type. Our findings indicate that proanthocyanidins coadministration and CYP3A4 genetic polymorphism can significantly influence crizotinib metabolism.

This study intended to evaluate the interactions between zamicastat and epoprostenol in healthy human subjects. This was a single-center, open-label, two-period study. In period 1, epoprostenol 8 ng/kg/min was administered alone. In period 2, epoprostenol 8 ng/kg/min was administered following an 8-day treatment with zamicastat. Since the initial dose of epoprostenol showed to be insufficiently tolerated, it was decreased to 6 ng/kg/min. Blood samples were collected to determine the metabolites of epoprostenol and concentrations of zamicastat and its metabolites. A total of 54 subjects were enrolled and data from 28 subjects were available for pharmacokinetic analysis. The epoprostenol plus zamicastat-to-epoprostenol geometric means ratio (GMR) and corresponding 90% confidence interval (CI) for Cav,ss and area under the plasma concentration-time curve from time 0 up to 16 h at steady state (AUC0-16,ss) of the metabolites of epoprostenol were within the acceptance bioequivalence range (80.00%-125.00%). The intrasubject coefficient of variation (ISCV) was below 10% for both parameters, on both metabolites. For zamicastat AUC0-τ,ss, the zamicastat plus epoprostenol-to-zamicastat GMR and corresponding 90% CI were within the bioequivalence acceptance range, while for zamicastat Cmax,ss, the lower limit of the 90% CI was slightly below the acceptance range. For zamicastat metabolites, Cmax,ss and AUC0-τ,ss and the zamicastat plus epoprostenol-to-zamicastat GMR were below the acceptance bioequivalence range. ISCV was between 30% and 41% for Cmax,ss and between 21% and 41% for AUC0-τ,ss, for zamicastat and both metabolites. This study showed that the administration of zamicastat did not significantly modify the cardiovascular effects of epoprostenol and that the interactions between zamicastat and epoprostenol are not expected to be clinically relevant.

Piperine (amide alkaloid) derived from pepper is globally utilized in diverse conventional and traditional systems of medicine. The co-administration of piperine has been observed to induce subtle modifications in the absorption, membrane transport, and drug metabolism of several high-efficacy medicines. The occurrence of medication interactions might have a notable impact on the pharmacokinetic parameters, resulting in either a favorable or unfavorable pharmacological effect. This comprehensive pharmacokinetic drug interaction evaluation of piperine encompasses a total of 34 scholarly articles (specific for pharmacokinetic interactions), consisting of 62 studies (56 preclinical studies and 6 clinical investigations). In this study, we propose that piperine has the ability to increase the bioavailability and bioactive molecules of a natural origin of a variety of medications, making it an effective bioenhancer. By enhancing bioavailability, piperine can reduce the required dosage, lower drug costs, minimize the occurrence of drug resistance, and mitigate dose-dependent side effects associated with various medications such as ciprofloxacin, ampicillin, metronidazole carbamazepine, curcumin, and oxytetracycline. However, a limited number of published studies have indicated a reduction in bioavailability following oral administration of isoniazid, puerarin, diltiazem, desacetyldiltiazem, and magnolol in combination with piperine or pepper/Trikatu (containing piperine majorly). Several other critical studies have demonstrated that there is no significant variation in pharmacokinetic characteristics along with piperine. The medications containing piperine have led to significant modifications in their pharmacokinetic properties, finally yielding advantageous outcomes for drugs with low bioavailability. Additionally, these alterations have resulted in reduced side effects and extended half-life (T1/2) for specific drugs.

BACKGROUND: Factors affecting serum concentrations of levetiracetam in dogs are unknown and could affect the efficacy of levetiracetam in controlling seizures in dogs with epilepsy.
OBJECTIVE: Higher PO doses of levetiracetam will be needed in dogs to achieve serum concentrations shown to be effective in humans. Determine factors that could influence serum levetiracetam concentrations and justify dose adjustment in some epileptic dogs.
METHODS: Sixty-nine client-owned dogs with epilepsy treated with levetiracetam alone or in combination, based on 127 trough serum concentration measurements of levetiracetam.
METHODS: Retrospective cohort study. Linear mixed models were used to assess the effect of patient signalment and concurrent drug administration on serum concentrations of levetiracetam and the effect of serum concentration of levetiracetam on seizure frequency reduction.
RESULTS: The PO dose of levetiracetam significantly explained changes in serum levetiracetam concentration, and this causal link was stronger with monotherapy (R2 = 0.59, P < .001). Phenobarbital significantly decreased serum levetiracetam concentration in a dose dependent manner (R2 = 0.30, P = .003). Based on our model, a levetiracetam dosage of 99-216 mg/kg/day is necessary to obtain a serum levetiracetam concentration of 20 μg/mL when used alone or concurrently with 7 mg/kg/day of phenobarbital. No other factors were found to influence serum levetiracetam concentrations. No therapeutic range could be identified.
CONCLUSIONS: Our data suggest that a dosage of 99-216 mg/kg/day of levetiracetam is needed to achieve a serum concentration known to be therapeutically effective in humans, especially when administered concomitantly with phenobarbital.

Dose selection for investigations of intrinsic and extrinsic factors of pharmacokinetic variability as well as safety is a challenging question in the early clinical stage of drug development. The dose of an investigational product is chosen considering the compound information available to date, feasibility of the assessments, regulatory requirements, and the intent to maximize information for later regulatory submission. This review selected 37 programs as case examples of recently approved drugs to explore the doses selected with focus on studies of drug interaction, renal and hepatic impairment, food effect and concentration-QTc assessment.The review found that regulatory agencies may consider alternative approaches if justified and safe as illustrated in these examples. It is thus recommendable to use the first in human trial as an opportunity to assess QT-prolongation and drug interactions using probes or endogenous markers while maximizing the DDI potential, increasing sensitivity and ensuring safety. Early understanding of dose proportionality assists dose finding and simple and fast to conduct DDI study designs are advantageous. Single dose impairment studies despite non-proportional/time-dependent PK are often acceptability.Overall, the early understanding of the drug\'s safety profile is essential to ensure the safety of doses selected while preventing clinical trials with unnecessary exposure when using high doses or multiple doses. The information collected in this retrospective survey is a good reminder to tailor the early clinical program to the profile and needs of the molecule and consider regulatory opportunities to streamline the development path.

UNASSIGNED: people living with HIV/AIDS using antiretroviral therapy sometimes present with comorbid conditions or co-infections. This could lead to an increased risk of drug interactions due to the concomitant use of drugs. The aim of the study was to explore the overall impact of dolutegravir on such comorbidities and the effect of concomitant medication on the safety and efficacy of dolutegravir.
UNASSIGNED: data was collected using a survey questionnaire and a retrospective review of medical records of a prospective study sample. Medical records were retrospectively reviewed for up to 12 months after dolutegravir initiation. Concomitantly used drugs and supplements that were identified to have a potential interaction with dolutegravir were further characterized. Descriptive and summary statistics were used to describe the data, t-tests were performed on blood glucose levels and cross-tabulations were done on some variables.
UNASSIGNED: of the 461 participants enrolled into the study, 172 (37.3%) and 54 (11.7%) experienced comorbidity and coinfection respectively. More than 50% of the participants used concomitant medicines. Metformin use led to increased blood glucose levels (p=0.009); participants on rifampicin (n=8) received an additional daily dose of dolutegravir. Virological outcomes in participants on sodium valproate (n=2) and St John´s wort (n=1) did not show safety concerns, whilst 3 dolutegravir discontinuations were observed in participants using supplements and antacids containing divalent cations.
UNASSIGNED: even though dolutegravir was safe and effective in the study population, with possible drug interactions leading to treatment discontinuations in only 3(0.7%) participants, further investigation into dolutegravir-induced hyperglycemia needs investigation.

Adverse events related to drug therapy are a major cause of iatrogenicity. They are responsible of increased morbidity, leading to hospitalization, sometimes in emergency, and mortality, not only in ambulatory care but also during hospitalization itself. Causes are multiple : among them, confusion leading to an erroneous drug administration, mistakes regarding dosage, risks associated to self-medication, drug-drug interactions or even food-drug interactions. Elderly population is exposed to an increased incidence of drug iatrogenicity because older patients cumulate numerous risk factors, especially polypharmacy and cognitive disorders. Prevention of drug iatrogenicity is a key objective from a public health point of view. Preventive measures should target the prescriber (physician), the dispenser (pharmacist), the user (patient) and the supplier (pharmaceutical industry).
Les manifestations indésirables liées à la prise des médicaments représentent une cause non négligeable d’iatrogénie. Elles sont responsables d’une morbidité, amenant des hospitalisations parfois en urgence, voire d’une mortalité, non seulement en ambulatoire mais aussi au sein même de l’hôpital. Les causes sont multiples. Citons, notamment, la confusion aboutissant à la prise d’un médicament erroné, les erreurs dans la posologie, les risques liés à l’auto-médication, les interactions médicamenteuses, ou encore, les interactions aliments- médicaments. La population âgée est particulièrement exposée car elle cumule nombre de facteurs de risque, dont la polymédication et les troubles cognitifs. La prévention de la iatrogénie médicamenteuse est donc un objectif prioritaire dans le domaine de la pharmacothérapie. Les mesures préventives devraient cibler le prescripteur (médecin), le délivreur (pharmacien), l’utilisateur (patient) et le fournisseur (industrie pharmaceutique).

The purpose of this study is to clarify the drug interaction profile of aumolertinib, and the influence of CYP3A4 genetic polymorphism on aumolertinib metabolic characteristics. Through microsomal enzyme reactions, we screened 153 drugs and identified 15 that significantly inhibited the metabolism of aumolertinib. Among them, telmisartan and carvedilol exhibited potent inhibitory activities in rat liver microsomes (RLM) and human liver microsomes (HLM). In vivo, the pharmacokinetic parameters of aumolertinib, including AUC and Cmax, were significantly altered when co-administered with carvedilol, with a notable decrease in the clearance rate CLz/F. Interestingly, the pharmacokinetic parameters of the metabolite HAS-719 exhibited a similar trend as aumolertinib when co-administered. Mechanistically, both telmisartan and carvedilol exhibited a mixed-type inhibition on the metabolism of aumolertinib. Additionally, we used a baculovirus-insect cell expression system to prepare 24 recombinant CYP3A4 microsomes and obtained enzymatic kinetic parameters using aumolertinib as a substrate. Enzyme kinetic studies obtained the kinetic parameters of various CYP3A4 variant-mediated metabolism of aumolertinib. Based on the relative clearance rates, CYP3A4.4, 5, 7, 8, 9, 12, 13, 14, 17, 18, 19, 23, 24, 33, and 34 showed significantly lower clearance rates compared to the wild-type. Among the different CYP3A4 variants, the inhibitory potency of telmisartan and carvedilol on the metabolism of aumolertinib also varied. The IC50 values of telmisartan and carvedilol in CYP3A4.1 were 6.68 ± 1.76 μM and 0.60 ± 0.25 μM, respectively, whereas in CYP3A4.12, the IC50 exceeded 100 μM. Finally, we utilized adeno-associated virus to achieve liver-specific high expression of CYP3A4*1 and CYP3A4*12. In the group with high expression of the less active CYP3A4*12, the magnitude of the drug-drug interaction was significantly attenuated. In conclusion, CYP3A4 genetic polymorphism not only influences the pharmacokinetic characteristics of aumolertinib, but also the inhibitory potency of telmisartan and carvedilol on it.

This study aimed to provide an understanding of the influence of eugenol on CYP1A2, 2C9, 2D6, and 3A4 in human liver microsomes (HLM). Specific substrate for CYP1A2, 2C9, 2D6, and 3A4 were incubated in HLM with or without eugenol. The formation of their respective metabolites was assessed with HPLC analytical methods. Eugenol at 1, 10 and 100 µM levels inhibited the activity of CYP1A2 and CYP2C9 by 23.38 %, 23.57 %, 39.80 % and 62.82 %, 63.27 %, 67.70 % respectively. While, CYP2D6 and CYP3A4 activity was decreased by 40.70 %, 45.88 %, 62.68 % and 37.41 %, 42.58 % and 67.86 % at 1, 10 and 100 µM eugenol level respectively. The IC50 value of eugenol for CYP2D6 and CYP3A4 was calculated as 11.09 ± 3.49 µM and 13.48 ± 3.86 µM respectively. Potential herb-drug interactions was noted when eugenol is administered simultaneously with medications metabolized by these enzymes, most notably CYP2C9, CYP2D6 and CYP3A4.

Cytochrome P450 3A4 (CYP3A4) is a crucial enzyme in the metabolism of xenobiotics, particularly in drug metabolism interactions (DDIs), making it a significant factor in clinical drug use. However, current assay techniques are both laborious and costly, making it difficult to construct a high-throughput monitoring method that can be used in conjunction with the clinic. This poses certain safety hazards for drug combination. Therefore, it is crucial to develop a synchronized monitoring method for the inhibition and induction of CYP3A4. In this study, we utilized 3D culture technology to develop a HepaRG cells spheroid model. The CYP450 and transporter expression, the albumin secretion, and urea synthesis capacity characteristics were analyzed. The NEN probe was utilized as a tracer molecule for CYP3A4. The fluorescence intensity of metabolites was characterized by laser confocal technique to determine the inhibition and expression of CYP3A4 in the HepaRG cell spheroid model by the antibiotics for sepsis. The results indicate that the HepaRG sphere model successfully possessed the physiological phenotype of the liver, which could be used for drug interaction monitoring. Through positive drug testing, NEN probe was able to achieve bidirectional characterization of CYP3A4 induction and inhibition. The monitoring method described in this paper was successfully applied to drug interaction monitoring of commonly used antibiotics in sepsis patients, which is a convenient and rapid monitoring method. The proposed method offers a new strategy for monitoring CYP3A4-mediated drug-drug interactions with a high-throughput assay, which will help to improve the safety of clinical drug combination.