Comparative cytochrome p450 in vitro inhibition by atypical antipsychotic drugs

Chlorpromazine's impact on Mytilus galloprovincialis: a multi-faceted investigation

The antipsychotic chlorpromazine (Cpz) has raised concern as a pharmaceutical effluent due to its wide medical applications. Moreover, its potent pro-oxidant properties and impact on the cell viability of the marine mollusc Mytilus galloprovincialis, even at low concentrations (ng/L), have been noted. Based on this evidence, in this study, we investigated the physiological effects of Cpz on M. galloprovincialis, to elucidate its fate within the organism, in terms of bioaccumulation, biotransformation, byssus changes and stress responses of the cellular thiolome. Histological and indicators of vitality analyses were also performed to better evaluate the influence of the drug on the morphology and cell viability of the digestive gland. To this end, two different concentrations of Cpz (Cpz I (12 ng/L or 37 pM) and Cpz II (12 μg/L or 37 nM)) were administered to mussels over 14 days. Cpz accumulation in the digestive gland significantly increased with water concentration (BCF of Cpz I and Cpz II). Biochemical analyses indicated lysosomal dysfunction, reflected in elevated total Cathepsin D activity and compromised lysosomal membrane stability. Stress-related and metal-buffering proteins (GST and metallothionein) responded to both Cpz concentrations. Cpz I induced phase I biotransformation activity (CYP450-dependent EROD), while Cpz II triggered caspase-3 activation, indicative of detoxification overload. Histological analysis revealed digestive gland atrophy, epithelial thinning, haemocyte infiltration, and brown cell presence. Byssus analysis showed significant alterations. In conclusion, our study underscores Cpz-induced physiological and histological changes in M. galloprovincialis, posing potential implications for mussel health and confirming the utilisation of this mussel as an indication of Cpz ecotoxicity.

Simulation of drug-drug interactions between breast cancer chemotherapeutic agents and antiemetic drugs

BACKGROUND

Chemotherapy-induced nausea and vomiting are commonly experienced side effects in breast cancer (BCa) patients. Antiemetic drugs used in BCa treatment are either inhibitors or inducers of cytochrome P450 (CYP) enzymes, while anticancer drugs are metabolized by CYPs.

OBJECTIVES

The purpose of the present work was to evaluate in silico drug-drug interaction (DDI) potential between BCa chemotherapeutic drugs and antiemetic agents.

METHODS

The Drug-Drug Interaction™ module of GastroPlus™ was employed to assess CYP-related interactions between antiemetic and anticancer therapy combinations. The CYP inhibitory or inducing parameters (IC50, Ki, EC50) used in simulations were obtained from the literature.

RESULTS

Analyses of twenty-three BCa drugs indicated that 22% of the chemotherapeutic drugs do not need an antiemetic agent due to their low emetogenicity, whereas 30% of the anticancer drugs are not metabolized by CYPs. The remaining eleven anticancer drugs metabolized by CYPs generated ninety-nine combinations with nine antiemetics. Simulation of DDIs suggest that about half of the pairs did not demonstrate any potential for DDI, whereas 30%, 10%, and 9% of the pairs showed weak, moderate, and strong interaction potential, respectively. In the present study, netupitant was the only antiemetic that showed strong inhibitory interactions (predicted AUC ratio > 5) with CYP3A4-metabolzied anticancer therapies (e.g., docetaxel, ribociclib, olaparib). Moderate to no interactions were observed with ondansetron, aprepitant, rolapitant, and dexamethasone in combination with anticancer agents.

CONCLUSION

It is critical to recognize that these interactions can get amplified in cancer patients because of the severity of the disease and chemotherapy toxicities. Clinicians need to be aware of the DDI likelihood of the drug combinations used in BCa treatment.

[Screening of potential non-azole inhibitors of lanosterol14-alpha demethylase (CYP51) of Candida fungi]

Currently, opportunistic fungi of the genus Candida are the main causative agents of mycoses, which are especially severe upon condition of acquired immunodeficiency. The main target for the development of new antimycotics is the cytochrome P450 51 (CYP51) of the pathogenic fungus. Due to the widespread distribution of Candida strains resistancy to inhibitors of the azole class, the screening for CYP51 inhibitors both among non-azole compounds and among clinically used drugs repurposing as antimycotics is becoming urgent. To identify potential inhibitors from the non-azole group, an integrated approach was applied, including bioinformatics analysis, computer molecular modeling, and a surface plasmon resonance (SPR) technology. Using in silico modeling, the binding sites for acetylsalicylic acid, ibuprofen, chlorpromazine and haloperidol (this compounds, according to the literature, showed antimycotic activity) were predicted in the active site of CYP51 of Candida albicans and Candida glabrata. The Kd values of molecular complexes of acetylsalicylic acid, ibuprofen and haloperidol with CYP51, determined by SPR analysis, ranged from 18 μM to 126 μM. It was also shown that structural derivatives of haloperidol, containing various substituents, could be positioned in the active site of CYP51 of Candida albicans with the possible formation of coordination bonds between the hydroxyl groups of the derivatives and the iron atom in the heme of CYP51. Thus, the potential basic structures of non-azole compounds have been proposed, which can be used for the design of new CYP51 inhibitors of Candida fungi.

In vitro inhibition of human cytochrome P450 enzymes by the novel atypical antipsychotic drug asenapine: a prediction of possible drug-drug interactions

BACKGROUND

Inhibition of cytochrome P450 (CYP) enzymes is the most common cause of harmful drug-drug interactions. The present study aimed at examining the inhibitory effect of the novel antipsychotic drug asenapine on the main CYP enzymes in human liver.

METHODS

The experiments were performed in vitro using pooled human liver microsomes and the human cDNA-expressed CYP enzymes: CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 (Supersomes). Activities of CYP enzymes were determined using the CYP-specific reactions: caffeine 3-N-demethylation (CYP1A2), diclofenac 4'-hydroxylation (CYP2C9), perazine N-demethylation (CYP2C19), bufuralol 1'-hydroxylation (CYP2D6), and testosterone 6β-hydroxylation (CYP3A4). The rates of the CYP-specific reactions were assessed in the absence and presence of asenapine using HPLC.

RESULTS

The obtained results showed that both in human liver microsomes and Supersomes asenapine potently and to a similar degree inhibited the activity of CYP1A2 via a mixed mechanism (K_i = 3.2 μM in liver microsomes and Supersomes) and CYP2D6 via a competitive mechanism (K_i = 1.75 and 1.89 μM in microsomes and Supersomes, respectively). Moreover, asenapine attenuated the CYP3A4 activity via a non-competitive mechanism (K_i = 31.3 and 27.3 μM in microsomes and Supersomes, respectively). In contrast, asenapine did not affect the activity of CYP2C9 or CYP2C19.

CONCLUSION

The potent inhibition of CYP1A2 and CYP2D6 by asenapine, demonstrated in vitro, will most probably be observed also in vivo, since the calculated K_i values are close to the presumed concentration range for asenapine in the liver in vivo. Therefore, pharmacokinetic interactions involving asenapine and CYP2D6 or CYP1A2 substrates are likely to occur during their co-administration to patients.

Evaluation of Herb-Drug Interactions of Hovenia dulcis Fruit Extracts

Background:

Hovenia dulcis (Rhamnaceae) fruits are popularly used as herbal medicines or dietary supplements in Asian countries due to functions such as liver protection and detoxification from alcohol poisoning. Accordingly, it is very likely for dietary supplemental products, including H. dulcis fruit extracts, to be taken with prescription drugs.

Objective:

In this study, possible food–drug interactions involving H. dulcis fruit extracts were evaluated based on the inhibition of cytochrome P450 (CYP) enzyme activity.

Material and Methods:

The water extract of H. dulcis fruit extracts was incubated in human liver microsomes with CYP-specific substrates. The formation of the CYP-specific metabolites was measured using liquid chromatography-tandem mass spectrometry.

Results:

H. dulcis fruit extracts showed negligible effects on seven CYP isozyme activities at all concentrations tested.

Conclusion:

This result suggests that H. dulcis fruit extracts may have minimal pharmacokinetic interactions with coadministered drugs through the modulation of CYP enzymes.

SUMMARY

Food-drug interactions involving H. dulcis fruit extracts were evaluated.

The inhibition of CYPs by H. dulcis extracts was tested.

H. dulcis extracts showed negligible effects on CYP activities.

H. dulcis extracts may have minimal pharmacokinetic interactions with co-administered drugs.

Abbreviations Used: CYP: cytochrome P450 enzymes, HPLC: High performance liquid chromatography, LC-MS/MS : liquid chromatography-tandem mass spectrometry, MRM: multiple-reaction monitoring

Inhibition of human cytochrome P450 isoenzymes by a phenothiazine neuroleptic levomepromazine: An in vitro study

BACKGROUND

Inhibition of cytochrome P450 (CYP) isoenzymes is the most common cause of harmful drug-drug interactions. The present study was aimed at examining the inhibitory effect of the phenothiazine neuroleptic levomepromazine on main CYP isoenzymes in human liver.

METHODS

The experiment was performed in vitro using the human cDNA-expressed CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4 (Supersomes). CYP isoenzyme activities were determined using the CYP-specific reactions: caffeine 3-N-demethylation (CYP1A2), diclofenac 4'-hydroxylation (CYP2C9), perazine N-demethylation (CYP2C19), bufuralol 1'-hydroxylation (CYP2D6) and testosterone 6β-hydroxylation (CYP3A4). The rates of the CYP-specific reactions were assessed in the absence and presence of levomepromazine (1-50 μM). The concentrations of CYP-specific substrates and their metabolites formed by CYP isoenzymes were measured by HPLC with UV or fluorimetric detection.

RESULTS

Levomepromazine potently inhibited CYP2D6 (K(i) = 6 μM) in a competitive manner. Moreover, the neuroleptic moderately diminished the activity of CYP1A2 (K(i) = 47 μM) and CYP3A4 (K(i) = 34 μM) via a mixed mechanism. On the other hand, levomepromazine did not affect the activities of CYP2C9 and CYP2C19.

CONCLUSION

The inhibition of CYP1A2, CYP2D6 and CYP3A4 by levomepromazine, demonstrated in vitro in the present study, should also be observed in vivo (especially the CYP2D6 inhibition by levomepromazine), since the calculated K(i) values are below or close to the presumed concentration range for levomepromazine in the liver in vivo. Therefore pharmacokinetic interactions involving levomepromazine and CYP2D6, CYP1A2 or CYP3A4 substrates are likely to occur in patients during co-administration of the above-mentioned substrates/drugs.

Drug-Drug Interactions With Antiviral Agents in People Who Inject Drugs Requiring Substitution Therapy

OBJECTIVE

To describe potential drug-drug interactions in the area of HIV/hepatitis C virus (HCV) coinfection and injection drug use, including those between antiretrovirals (ARVs), direct-acting antivirals (DAAs), and opioid-agonist therapy, and to supply a practical approach to their management.

DATA SOURCES

We searched PubMed for relevant articles published up until February 2015 as well as conference reports and drug-drug-interaction Web sites.

DATA SELECTION AND DATA EXTRACTION

We used the following search terms: pharmacokinetic and pharmacodynamic drug-drug interaction, opioid substitution, HIV, hepatitis and the individual names of the relevant agents of the following drug classes and the drug classes itself: reverse transcriptase inhibitors, nonnucleoside reverse transcriptase inhibitors, protease inhibitors, direct-acting antivirals, opioide, benzodiazepines, anticonvulsants, antidepressants and antipsychotics. Additional references were identified from a review of literature citations and drug-drug interaction Web sites. In our evaluation, we included German- and English-language studies and reports addressing drug-drug interactions between opioid agonist therapy and ARVs or DAAs.

DATA SYNTHESIS

Pharmacokinetic data were available for all ARVs and DAAs except rilpivirine, indinavir, saquinavir, maraviroc, dolutegravir, and MK-8742 with buprenorphine as well as maraviroc with methadone Drug-drug interactions of potential clinical relevance are most likely to occur between opioid-replacement therapy and ARVs, particularly the nonnucleoside reverse transcriptase inhibitors, efavirenz and nevirapine, and HIV protease inhibitors.

CONCLUSION

Integrase inhibitors may be safely coadministered with opioid-replacement therapy. With respect to HCV DAAs, most currently approved and late-stage investigational agents do not have clinically significant interactions with opioid-replacement therapy. ARV and DAAs may interact with other drug classes commonly used in the opioid-dependent population, including benzodiazepines, antidepressants, anticonvulsants, and antipsychotics.

[Carbamazepine and psychotropic treatment interaction: Two case studies of carbamazepine overdosage]

Drug interaction is a frequent situation in pediatrics and child psychiatry. Carbamazepine (CBZ) is an antiepileptic drug used as a mood stabilizer in child psychiatry. CBZ is known to be a potent inducer of various CYP isoenzymes of cytochrome P450, which might result in a decrease in the plasma concentration of associated treatments. We describe two cases of CBZ overdosage in adolescent inpatients (14 and 16 years). The patients were treated with risperidone associated with fluoxetine in one and with loxapine in the other case, and CBZ was introduced as a mood stabilizer. Patients presented typical clinical symptoms (fatigue, dizziness, gastrointestinal signs, blurred vision). Overdosage was confirmed by an elevated CBZ plasma concentration (17 and 15.5 mg/L, therapeutic range 4-12 mg/L). We recommend introducing CBZ very progressively in patients treated with psychotropics, particularly when it is associated to several treatments. An intensification of clinical and biological follow-up with early plasma concentration testing should allow for better treatment adjustment.