Designer benzodiazepine rat pharmacokinetics: A comparison of alprazolam, flualprazolam and flubromazolam.

Designer benzodiazepines, including flualprazolam and flubromazolam, are clandestinely produced to circumvent federal regulations. Although flualprazolam and flubromazolam are structurally similar to alprazolam, they do not have an approved medical indication. Flualprazolam differs from alprazolam by the addition of a single fluorine atom. Whereas, flubromazolam differs by the addition of a single fluorine atom and substitution of a bromine for a chlorine atom. The pharmacokinetics of these designer compounds have not been extensively evaluated. In the present study, we evaluated flualprazolam and flubromazolam in a rat model and compared the pharmacokinetics of both compounds to alprazolam. Twelve male, Sprague-Dawley rats were given a 2 mg/kg subcutaneous dose of alprazolam, flualprazolam and flubromazolam and plasma pharmacokinetic parameters were evaluated. Both compounds displayed significant two-fold increases in volume of distribution and clearance. Additionally, flualprazolam displayed a significant increase in half-life leading to a nearly double half-life when compared to alprazolam. The findings of this study demonstrate that fluorination of the alprazolam pharmacophore increases pharmacokinetic parameters including half-life and volume of distribution. The increase in these parameters for flualprazolam and flubromazolam leads to an overall increased exposure in the body and a potential for greater toxicity than alprazolam.

The use of GA-RxODE (Genetics Algorithms and Running simulations from Ordinary Differential Equations-based model) method to optimize bioequivalence studies.

Bioequivalence (BE) studies are prerequisite in generic products approval. Normally, they are quite simple in design and expensive in execution, and sometimes suffer ethical questioning. Genetics Algorithms and Running simulations from Ordinary Differential Equations-based model (GA-RxODE) is a multipurpose method used in pharmacokinetic (PK) optimization. It can be used to complete concentration-time (C-T) missing data. In this investigation, GA-RxODE was applied in BE field. For this purpose, three BE studies were selected as a source data comprising formulations of metformin, alprazolam and clonazepam. From them, five blood samples values per volunteer-round from specific preset times were chosen as if BE study was carried out with five instead of the classic 10-20 samples. With the five values of each volunteer a complete C-T curve was simulated by GA-RxODE and certain PK estimation parameters (as maximum concentration, Cmax , and area under C-T curve from zero to infinite, AUCinf ) were elicited. Finally, with these modeled parameters, a BE analysis was performed according to certain regulatory agencies guidances. Some results, expressed as geometric mean ratios of compared formulations and their 90% confidence intervals (CI90), were as follows: Metformin Cmax  = 0.954 (0.878-1.035), AUCinf  = 0.949 (0.881-1.022); Alprazolam Cmax  = 1.063 (0.924-1.222), AUCinf  = 1.036 (0.857-1.249), Clonazepam Cmax  = 0.927 (0.831-1.034), and AUCinf  = 1.021 (0.931-1.119). All CI90 were inside the 0.8-1.25 BE range. In summary, the simulated data were bioequivalent and non-significantly different from original studies' data. This raises the opportunity to perform more economic BE studies to build reliable PK estimation parameters from a few samples per volunteer.

Feasibility of physiologically based pharmacokinetic simulations for assessing pediatric patients after accidental drug ingestion: A case study of a 1.4-year-old girl who ingested alprazolam.

The accidental ingestion of drugs is a common concern, especially in the case of young children. A physiologically based pharmacokinetic (PBPK) model that implements the age-dependent size growth and ontogeny of organ functions can be used to predict the concentration-time profiles of drugs in the pediatric population. In this study, the feasibility of using a PBPK model for predicting the amount of drug accidentally swallowed by a child was assessed based on a case study in an infant. Alprazolam was the drug involved in the current case. The developed PBPK model of alprazolam was first evaluated using pharmacokinetic data obtained in healthy adult male volunteers. Then, it was adapted for application to virtual Japanese pediatric subjects having the same demographic information as the infant of interest. The pharmacokinetic data observed in the infant fell within the range of the 5th and 95th percentiles of the pharmacokinetic simulations after administration of 0.4 mg alprazolam (equivalent to one tablet) in the panel of virtual infants. PBPK simulations could provide estimates of the amount accidentally ingested by a child and also give mechanistic insights into the observed drug concentrations. The current study demonstrates the potential clinical utility of PBPK modeling.

Post-mortem Redistribution of Alprazolam in Rats.

The post-mortem toxicological findings may be misinterpreted, if the drug undergoes substantial post-mortem redistribution. As alprazolam is one of the most frequently evaluated drug for legal/forensic reasons in drug-related fatalities, we studied possible changes in alprazolam distribution after death in a rat model. Rats were sacrificed 30 minutes after alprazolam administration. Blood and tissue samples from 8 animals per sampling time were collected at 0, 2, 6, and 24 h after death. The experimental samples were assayed for alprazolam using validated UHPLC-PDA method. Median blood alprazolam concentrations increased approximately 2 times compared with ante-mortem levels due to the redistribution during early post-mortem phase and then slowly decreased with a half-life of 60.7 h. The highest alprazolam tissue concentrations were found in fat and liver and the lowest levels were observed in lungs and brain. The median amount of alprazolam deposited in the lungs was relatively stable over the 24-h post-mortem period, while in heart, liver and kidney the deposited proportion of administered dose increased by 43-48% in comparison with ante-mortem values indicating continuous accumulation of alprazolam into these tissues. These results provide evidence needed for the interpretation of toxicological results in alprazolam-related fatalities and demonstrate modest alprazolam post-mortem redistribution.

Evaluation of Erythromycin as a Tool to Assess CYP3A Contribution of Low Clearance Compounds in a Long-Term Hepatocyte Culture.

Long-term hepatocyte culture systems such as HepatoPac are well suited to evaluate the metabolic turnover of low clearance (CL) drugs because of their sustained metabolic capacity and longer-term viability. Erythromycin (ERY), a moderate, mechanism-based inhibitor of CYP3A, was evaluated as a tool in the HepatoPac model to assess contribution of CYP3A to the clearance of drug candidates. ERY inhibited CYP3A activity by 58% and 80% at 3 and 10 µM, respectively, for up to 72 hours. At 30 µM, ERY inhibited midazolam hydroxylation by >85% for the entire 144-hour duration of the incubation. Alprazolam CLint was inhibited 58% by 3 µM of ERY, 75% by 15 µM of ERY, 89% by 30 µM of ERY, and 94% by 60 µM of ERY. ERY (30 µM) did not markedly affect CLint of substrates for several other major cytochrome P450 isoforms evaluated and did not markedly inhibit uridine diphosphoglucuronosyl transferase (UGT) isoforms 1A1, 1A3, 1A4, 1A6, 1A9, 2B7, or 2B15 as assessed using recombinant UGTs. ERY only mildly increased CYP3A4 gene expression by 2.1-fold (14% of rifampicin induction) at 120 µM, indicating that at effective concentrations for inhibition of CYP3A activity (30-60 µM), arylhydrocarbon receptor, constitutive androstane receptor, and pregnane-X-receptor activation are not likely to markedly increase levels of other drug-metabolizing enzymes or transporters. ERY at concentrations up to 60 µM was not toxic for up to 6 days of incubation. Use of ERY to selectively inhibit CYP3A in high-functioning, long-term hepatocyte models such as HepatoPac can be a valuable strategy to evaluate the contribution of CYP3A metabolism to the overall clearance of slowly metabolized drug candidates. SIGNIFICANCE STATEMENT: This work describes the use of erythromycin as a selective inhibitor of CYP3A to assess the contribution of CYP3A in the metabolism of compounds using long-term hepatocyte cultures.

Effects of plasma concentration of micro-RNA Mir-27b and CYP3A4*22 on equilibrium concentration of alprazolam in patients with anxiety disorders comorbid with alcohol use disorder.

Alprazolam is used in the treatment of patients with anxiety disorders comorbid with alcohol use disorder. Some proportion of these patients does not respond adequately to treatment with alprazolam, while many of them experience dose-dependent adverse drug reactions. Results of the previous studies have shown that CYP3A is involved in the biotransformation of alprazolam, the activity of which is dependent, inter alia, on the polymorphism of the encoding gene. OBJECTIVE: The objective of our study was to investigate the effect of 99366316G>A polymorphism of the CYP3A4 gene on the concentration/dose indicator of alprazolam in patients with anxiety disorders comorbid with alcohol use disorder, using findings on enzymatic activity of CYP3A (as evaluated by the 6-beta-hydroxy-cortisol/cortisol ratio measurement) and on CYP3A4 expression level obtained by measuring the miR-27b plasma concentration levels in patients with anxiety disorders comorbid with alcoholism. MATERIAL AND METHODS: Our study enrolled 105 patients with anxiety disorders comorbid with alcohol use disorder (age - 37.8±14.6 years). Therapy included alprazolam in an average daily dose of 5.6±2.4 mg per day. Treatment efficacy was evaluated using the psychometric scales. Therapy safety was assessed using the UKU Side-Effect Rating Scale. For genotyping and estimation of the microRNA (miRNA) plasma levels, we performed the real-time polymerase chain reaction. The activity of CYP3A was evaluated using the HPLC-MS/MS method by the content of the endogenous substrate of the given isoenzyme and its metabolite in urine (6- beta-hydroxy-cortisol/cortisol). Therapeutic drug monitoring (TDM) has been performed using HPLC-MS/MS. RESULTS: Our study revealed the statistically significant results in terms of the treatment efficacy evaluation (HAMA scores at the end of the treatment course): (GG) 3.0 [2.0; 5.0] and (GA) 4.0 [4.0; 5.0], p = 0.007; at the same time, the statistical significance in the safety profile was not obtained (the UKU scores): (GG) 3.0 [2.0; 3.8] and (GA) 3.0 [1.5; 4.0], p = 0.650. We revealed a statistical significance for concentration/dose indicator of alprazolam in patients with different genotypes: (GG) 1.583 [0.941; 2.301] and (GA) 2.888 [2.305; 4.394], p = 0.001). Analysis of the results of the pharmacotranscriptomic part of the study didn't show the statistically significant difference in the miR-27b plasma levels in patients with different genotypes: (GG) 25.6 [20.4; 28.8], (GA) 25.7 [19.7; 33.1], p = 0.423. At the same time, correlation analysis revealed a statistically significant relationship between the alprazolam efficacy profile evaluated by changes in HAMA scale scores and the miR-27b plasma concentration: rs = 0.20, p = 0.042. Also, we didn't reveal the correlation between the miRNA concentration and safety profile: rs = 0.15, p = 0.127. In addition, we revealed the relationship between the CYP3A enzymatic activity (as evaluated by 6-beta-hydroxycortisol/ cortisol ratio measurement) and the miR-27b plasma concentration: rs = -0.27, p = 0.006. At the same time, correlation analysis revealed a statistically significant relationship between the alprazolam concentration and the miR-27b plasma concentration: rs = 0.28, p = 0.003. CONCLUSION: The effect of genetic polymorphism of the CYP3A4 gene on the efficacy and safety profiles of alprazolam was demonstrated in a group of 105 patients with anxiety disorders comorbid with alcohol use disorder. At the same time, miR-27b remains a promising biomarker for assessing the level of CYP3A4 expression, because it correlates with the encoded isoenzyme's activity.

Pharmacokinetic assessment of alprazolam-induced neonatal abstinence syndrome using physiologically based pharmacokinetic model.

Sustained benzodiazepine use during pregnancy can induce neonatal abstinence syndrome (NAS). In this study, the association between NAS and plasma alprazolam concentration was examined using the measured neonatal concentrations in the time series as well as simulated plasma concentrations of pregnant woman and neonate by physiologically based pharmacokinetic (PBPK) modeling. A neonate born to a mother taking alprazolam daily throughout pregnancy exhibited symptoms such as apnea and vomiting from 9 h to 4 days after birth. Finnegan score was 7 at birth and decreased to 0 by day 4. Apnea improved by 24 h post-delivery and gastrointestinal symptoms disappeared by day 4. The plasma alprazolam concentration in the neonate was 15.2 ng/mL immediately after birth and gradually decreased over 3 days. Measured neonate and estimated maternal plasma alprazolam concentrations were within the 90% prediction intervals of each concentration by PBPK simulation using "pregnancy" and "pediatrics" population parameters including in Simcyp population-based ADME simulator. In conclusion, NAS symptoms such as apnea and digestive events disappeared in parallel with the decrease of the neonate's plasma alprazolam concentrations. Moreover, PBPK modeling and simulation is a useful methodology for toxicological assessment in special characteristics populations lacking specific experimental data.

Quantification of eight benzodiazepines in human breastmilk and plasma by liquid-liquid extraction and liquid-chromatography tandem mass spectrometry: Application to evaluation of alprazolam transfer into breastmilk.

Breastfeeding is strongly encouraged for infant and maternal health. Benzodiazepines (BZDs) are widely prescribed drugs for symptoms, such as anxiety and insomnia, which many women could experience during the postpartum period. However, limited information is currently available to evaluate the transfer of different BZDs into breastmilk. In order to assess the proprieties of this medication during breastfeeding, robust and sensitive analytical methods to quantify BZDs are required. For this purpose, we developed a method for quantification of BZDs, including alprazolam, bromazepam, clonazepam, clotiazepam, etizolam, flunitrazepam, lorazepam, and CM7116 (a metabolite of ethyl loflazepate), in human breastmilk and plasma using liquid chromatography/tandem mass spectrometry (LC/MS/MS). Sample preparation was performed by a simple liquid-liquid extraction (LLE) with ethyl acetate. For sample preparation of CM7116, the pretreatment process to completely obtain the metabolite was added before the LLE step. The BZDs were separated by a C18 column using a gradient elution of acetonitrile in aqueous ammonium acetate solution, and were detected in the positive ion electrospray mode with multiple reaction monitoring (MRM). Lower limits of quantification (LLOQs) in breastmilk ranged from 0.25 to 0.5 ng/mL, and those in plasma ranged from 0.5 to 1.0 ng/mL. The intra-day and inter-day precision, and accuracy of data were assessed and found to be acceptable. The developed method was successfully applied to measure the concentration of alprazolam in breastmilk and plasma, which were donated by a lactating woman who had been regularly treated with alprazolam. Milk to plasma (M/P) ratios were calculated as 0.52 (before oral administration) and 0.49 (2 h after administration) 3 days after delivery. The M/P ratio 1 month after delivery was calculated as 0.41 (2 h after administration). We estimated that the relative infant dose (RID) values of alprazolam ranged from 3.11 to 4.61%.

Physiologically Based Pharmacokinetic Modelling of Hyperforin to Predict Drug Interactions with St John's Wort.

BACKGROUND AND OBJECTIVES: Herb-drug interactions with St John's wort (SJW) have been widely studied in numerous clinical studies. The objective of this study was to develop and evaluate a physiologically based pharmacokinetic (PBPK) model for hyperforin (the constituent of SJW responsible for interactions), which has the potential to provide unique insights into SJW interactions and allow prediction of the likely extent of interactions with SJW compared to published interaction reports. METHODS: A PBPK model of hyperforin accounting for the induction of cytochrome P450 (CYP) 3A, CYP2C9 and CYP2C19 was developed in the Simcyp® Simulator (version 17) and verified using published, clinically observed pharmacokinetic data. The predictive performance of this model based on the prediction fold-difference (expressed as the ratio of predicted and clinically observed change in systemic exposure of drug) was evaluated across a range of CYP substrates. RESULTS: The verified PBPK model predicted the change in victim drug exposure due to the induction by SJW (expressed as area under the plasma concentration-time curve (AUC) ratio) within 1.25-fold (0.80-1.25) of that reported in clinical studies. The PBPK simulation indicated that the unbound concentration of hyperforin in the liver was far lower than in the gut (enterocytes). Simulations revealed that induction of intestinal CYP enzymes by hyperforin was found to be more pronounced than the corresponding increase in liver CYP activity (15.5- vs. 1.1-fold, respectively, at a hyperforin dose of 45 mg/day). CONCLUSION: In the current study, a PBPK model for hyperforin was successfully developed, with a predictive capability for the interactions of SJW with different CYP3A, CYP2C9 and CYP2C19 substrates. This PBPK model is valuable to predict the extent of herb-drug interactions with SJW and help design the clinical interaction studies, particularly for new drugs and previously unstudied clinical scenarios.

Influence of ethanol on the metabolism of alprazolam.

BACKGROUND: Alprazolam is a commonly used benzodiazepine in clinical practice, and when coingested with ethanol, alprazolam can increase behavioral irritability and aggression. However, the mechanism of its interaction with ethanol remains unknown. RESEARCH DESIGN AND METHODS: The pharmacokinetics of alprazolam was studied in vivo in rat experiments involving the simultaneous administration of alprazolam and ethanol, and the interactions between ethanol and alprazolam were investigated in vitro in human liver microsomes. In silico molecular docking was applied to analyze the change in the CYP3A4-alprazolam-binding conformation when ethanol was coadministered with alprazolam. RESULTS: Compared with alprazolam administered alone (2 mg/kg), the Cmax of alprazolam increased when ethanol was simultaneously administered at 3 g/kg. The concentrations of alprazolam significantly increased by 39%, 17%, 105%, and 642% at 5, 10, 30, and 120 min intervals in the brain when coadministered with ethanol, respectively. Molecular docking results suggested that the conformation of CYP3A4 with alprazolam changed when ethanol was bound to the SER119 residue, which seems critical in the process of CYP3A4-alprazolam binding. CONCLUSIONS: Ethanol might increase the toxicity of alprazolam by inhibiting the activity of CYP3A4, although other pharmacokinetic processes may be affected. Ethanol could change the conformation of CYP3A4 and affect alprazolam binding.

Does using alprazolam during outpatient flexible cystoscopy decrease anxiety and pain? / ¿Disminuye el Alprazolam la ansiedad y el dolor durante la cistoscopia flexible ambulatoria?

OBJECTIVES: To evaluate the effect of pre-operative alprazolam medication on anxiety and pain in flexible cystoscopy for bladder cancer follow-up. METHODS: A total of 86 male patients who had flexible cystoscopy for bladder cancer follow-up at 6th and 9th months were included in the study. A visual analog scale (VAS) pain score and the State-Trait Anxiety Inventory (STAI) were used. The 6th (VAS-1) and 9th (VAS-2) month pain scores and 6th month STAI score (STAI-1) and, 9th month STAI score before (STAI-2a) and after alprazolam (0.5 mg) intake (STAI-2b) were compared. RESULTS: The mean age was 66.49±12.45 years. Patients were grouped by age≤65 (Group-1) and age≥66 (Group-2). Mean VAS score for VAS-1 and VAS-2 were 2.66±0.96 and 2.44±1.05, respectively (p = 0.007). The mean VAS-1 and VAS-2 scores in Group 1 were 3.0±1.05 and 2.73±1.18, respectively (p = 0.009). The mean VAS-1 and VAS-2 scores in Group 2 were 2.36±0.77 and 2.17±0.86 respectively (p = 0.031). The differences between mean anxiety scores were all statistically significant. All STAI (1, 2a, and 2b) and VAS (1 and 2) scores in Group-1 were statistically significantly higher than Group-2. Increasing STAI score is associated with a statistically significant increase in the VAS scores in the 0.50 and 0.75 quantiles (p = 0.021 and p = 0.039, respectively). CONCLUSIONS: Using alprazolam before flexible cystoscopy reduces both anxiety (STAI-1 vs STAI-2b) and pain (VAS-1 vs VAS-2). Previous cystoscopy experience reduces anxiety (STAI-2a vs. STAI-2b). Elderly patients have less anxiety and pain scores than younger patients in flexible cystoscopy

OBJETIVOS: Evaluar el efecto del alprazolam preoperatorio sobre la ansiedad y el dolor durante la cistoscopia flexible en el seguimiento del cáncer vesical. Métodos Se incluyeron 86 pacientes varones en seguimiento con cistoscopia flexible por cáncer vesical a los 6 y 9 meses. Se utilizaron una escala visual analógica (EVA) para el dolor y el Formulario STAI (State-trait anxiety Inventory) de ansiedad. Se compararon los resultados de dolor al 6º (EVA1) y 9º mes (EVA2) y los resultados del formulario STAI al 6º (STAI 1) y 9º mes, antes (STAI 2a) y después de la toma de alprazolam (STAI 2b). RESULTADOS: La edad media fue de 66,49±12,45 años. Los pacientes se agruparon por edad ≤ 65 años (Grupo 1) y ≥ 66 (Grupo 2). Las puntuaciones de la EVA 1 y EVA 2 fueron 2,66±0,96 y 2,44±1,05, respectivamente (p = 0,007). La media de las puntuaciones EVA 1 y EVA 2 en el grupo 1 fueron 3,0±1,05 y 2,73±1,18, respectivamente (p = 0,009). La media de las puntuaciones EVA 1 y EVA 2 en el grupo 2 fueron 2,36±0,77 y 2,17±0,86, respectivamente (p = 0,031). Las diferencias entre las puntuaciones medias de ansiedad fueron todas significativas. Todas las STAI (1, 2a y 2b) y EVA (1 y 2) en el grupo 1 fueron superiores a las del grupo 2, con diferencias estadísticamente significativas.Una puntuación del STAI creciente se asocia con un aumento significativo de las puntuaciones de la EVA en los cuartiles 0,50 y 0,75 (p = 0,021 y p = 0,039, respectivamente). CONCLUSIONES: La utilización de alprazolam antes de la cistoscopia flexible reduce tanto la ansiedad (STAI-1 vs STAI-2b) como el dolor (EVA-1 vs EVA-2). La experiencia de cistoscopia previa reduce la ansiedad (STAI-2a vs. STAI-2b). Los pacientes ancianos tienen valores más bajos de ansiedad y dolor en la cistoscopia flexible que los pacientes jóvenes

CYP3A4-based drug-drug interaction: CYP3A4 substrates' pharmacokinetic properties and ketoconazole dose regimen effect.

The aim of the study was to assess the magnitude of the CYP3A4 inhibitory effect of 2 dosing regimens of ketoconazole and the influence of the pharmacokinetic properties of the CYP3A4 substrate on the extent of the substrate exposure increase. For this purpose, a clinical study was conducted and PBPK modeling simulations were performed. A crossover study was conducted in healthy subjects. The study was designed to compare the effects of different regimens of reversible CYP3A4 inhibitors, i.e., ketoconazole 400 mg OD, ketoconazole 200 mg BID, on two CYP3A4 substrates, alprazolam and midazolam, reflecting different pharmacokinetic properties in terms of first-pass effect and elimination. In parallel, time-based simulations were performed using the Simcyp population-based Simulator to address the usefulness of modeling to assess interaction clinical study design with CYP3A4 substrates. Comparison of the OD versus BID regimens for ketoconazole showed an opposite trend for the 2 substrates: BID (200 mg) dosing regimen provided the maximal clearance inhibition for alprazolam, while it was OD (400 mg) dosing regimen for midazolam. However, these effects are moderate despite the well-known pharmacokinetic differences between these substrates, suggesting that these differences are not enough. In the other way round, these investigations show how two CYP3A4 substrates can be different without leading to a major impact of the ketoconazole dosing regimen. The clinical findings are consistent with the Simcyp predictions, in particular the opposite trend observed with midazolam and alprazolam and the ketoconazole dosing regimen. These clinical investigations showed the influence of the CYP3A4 substrates' pharmacokinetic properties and the relevance of ketoconazole dose regimen on the magnitude of the interaction ratios. In addition, PBPK Simcyp simulations demonstrated how they can be used to help clinical study design assessment to capture the maximum effect.

Evaluation of Cytochrome P450 (CYP) 3A4-Based Interactions of Levomilnacipran with Ketoconazole, Carbamazepine or Alprazolam in Healthy Subjects.

BACKGROUND AND OBJECTIVES: Levomilnacipran is a serotonin and norepinephrine reuptake inhibitor with balanced potency for the reuptake inhibition of norepinephrine and serotonin, approved in the USA for the treatment of major depressive disorder (MDD) in adults. We conducted studies in healthy human subjects to investigate pharmacokinetic interactions when levomilnacipran extended-release (ER) is administered in combination with an inhibitor (ketoconazole), an inducer (carbamazepine), or a substrate (alprazolam) of cytochrome P450 (CYP) 3A4. METHODS: Randomised, open-label studies were conducted in healthy volunteers (n = 34 ketoconazole, n = 34 carbamazepine, n = 30 alprazolam) and pharmacokinetic parameters were determined when levomilnacipran was administered alone or together with the relevant study drug. RESULTS: Co-administration of ketoconazole with levomilnacipran ER increased levomilnacipran maximum concentration (C max) by 39% [90% confidence interval (CI) 31-47%] and area under the concentration-time curve (AUC) by 57% (90% CI 47-67%), whereas carbamazepine reduced the C max and AUC of levomilnacipran by 26% (90% CI 22-30%) and 29% (90% CI 26-32%), respectively. Levomilnacipran at steady state had no significant effect on the pharmacokinetics of a single 1 mg dose of alprazolam extended release (XR); neither did single-dose alprazolam XR affect the steady-state pharmacokinetics of levomilnacipran. No new safety concerns were noted in these studies. CONCLUSIONS: Based on these results, the levomilnacipran ER dose should not exceed 80 mg once daily when used with ketoconazole, compared to 120 mg once daily in the absence of ketoconazole. No dose adjustment for levomilnacipran is suggested when levomilnacipran ER is co-administered with carbamazepine or other CYP3A4 inducers. Co-administration with levomilnacipran of drugs metabolised by CYP3A4, such as alprazolam, requires no dose adjustment due to pharmacokinetic considerations.

Pharmacokinetics and physiologic effects of alprazolam after a single oral dose in healthy mares.

The objective of this study was to evaluate the pharmacokinetic properties and physiologic effects of a single oral dose of alprazolam in horses. Seven adult female horses received an oral administration of alprazolam at a dosage of 0.04 mg/kg body weight. Blood samples were collected at various time points and assayed for alprazolam and its metabolite, α-hydroxyalprazolam, using liquid chromatography/mass spectrometry. Pharmacokinetic disposition of alprazolam was analyzed by a one-compartmental approach. Mean plasma pharmacokinetic parameters (±SD) following single-dose administration of alprazolam were as follows: Cmax 14.76 ± 3.72 ng/mL and area under the curve (AUC0-∞ ) 358.77 ± 76.26 ng·h/mL. Median (range) Tmax was 3 h (1-12 h). Alpha-hydroxyalprazolam concentrations were detected in each horse, although concentrations were low (Cmax 1.36 ± 0.28 ng/mL). Repeat physical examinations and assessment of the degree of sedation and ataxia were performed every 12 h to evaluate for adverse effects. Oral alprazolam tablets were absorbed in adult horses and no clinically relevant adverse events were observed. Further evaluation of repeated dosing and safety of administration of alprazolam to horses is warranted.

Metabolism of alprazolam (a marker of CYP3A4) in hemodialysis patients with persistent inflammation.

OBJECTIVE: To investigate the impact of persistent inflammation in hemodialysis (HD) patients on the pharmacokinetics of alprazolam, a cytochrome P450 (CYP) 3A4 substrate, and its metabolites and the role of HD in the impact of persistent inflammation in this clinical context. METHODS: The study population comprised 26 HD patients (mean age 64 years, range 27-79 years; 19 men, 7 women) who were given 1 mg of alprazolam orally in the evening before the day of HD. Unconjugated and conjugated alprazolam and its 4-hydroxy and α-hydroxy metabolites were measured by liquid chromatography-mass spectrometry at 10, 34 (start of HD) and 38 (end of HD) h after intake. C-reactive protein (CRP) was measured weekly beginning 2 months before study initiation, and alpha 1-acid glycoprotein and 4ß-hydroxycholesterol were measured at baseline. CYP3A4 activity was estimated as the ratio of unconjugated alprazolam to 4-hydroxyalprazolam between 10 and 34 h following alprazolam intake. RESULTS: After a single dose of alprazolam, plasma concentrations of unconjugated alprazolam and its metabolites decreased gradually, and unconjugated 4-hydroxyalprazolam was eliminated more rapidly than unconjugated alprazolam by HD. In contrast, the plasma concentrations of conjugated alprazolam and its conjugated metabolites increased during the 34 h following drug intake and the subsequent HD decreased their levels by almost 80%. The ratio of unconjugated alprazolam to 4-hydroxyalprazolam was correlated with CRP levels (r(s) = 0.49, P = 0.01). There was no significant correlation between CYP3A4 activity measured by alprazolam (4-hydroxylation) and alpha 1-acid glycoprotein or 4ß-hydroxycholesterol. Conjugated alprazolam was also found in the plasma. CONCLUSIONS: The correlation between CYP3A4 activity (assessed by alprazolam 4-hydroxylation) and CRP level suggests that inflammation may downregulate CYP3A4 activity. If confirmed, this could have major implications for drug dosing in persistently inflamed patients.

Transdermal delivery of alprazolam from a monolithic patch: formulation based on in vitro characterization.

Alprazolam, a benzodiazepine widely used for the treatment of psychiatric disorders, has been aimed to be formulated in a transdermal delivery system (TDS) prototype. A series of TDS prototypes dosed in all cases at 0.35 mg·cm(-2) of alprazolam were prepared as a monolithic drug in adhesive matrix using acrylic pressure-sensitive adhesives (PSA) of acrylate vinyl acetate (Duro-tack(®)). The effects of several permeation enhancers as azone, transcutol, propylene glycol, dodecyl alcohol, decyl alcohol, diethanolamine, N-methyl pyrrolidone and lauric acid were studied. Prototypes have been characterized based on adhesion parameters (peel adhesion and shear adhesion), in vitro human skin permeation and in vitro drug release according to European Pharmacopoeia for the selected prototype. Best results show that a combination of permeation enhancers from different chemical groups is able to provide almost a 33 fold increase in the transdermal alprazolam flux of an aqueous saturated dispersion (from 0.054 ± 0.019 to 1.76 ± 0.21 µg h.cm(-2)). Based on these in vitro flux data, a predictive simulation of the achievable plasmatic levels was performed assuming a constant systemic infusion of drug. In summary, it is possible to obtain a prototype of a TDS of alprazolam with adequate adhesive properties (peel adhesion and shear adhesion) and able to predict sustained therapeutic plasmatic levels.

Cross-conditional entropy and coherence analysis of pharmaco-EEG changes induced by alprazolam.

RATIONALE: Quantitative analysis of electroencephalographic signals (EEG) and their interpretation constitute a helpful tool in the assessment of the bioavailability of psychoactive drugs in the brain. Furthermore, psychotropic drug groups have typical signatures which relate biochemical mechanisms with specific EEG changes. OBJECTIVES: To analyze the pharmacological effect of a dose of alprazolam on the connectivity of the brain during wakefulness by means of linear and nonlinear approaches. METHODS: EEG signals were recorded after alprazolam administration in a placebo-controlled crossover clinical trial. Nonlinear couplings assessed by means of corrected cross-conditional entropy were compared to linear couplings measured with the classical magnitude squared coherence. RESULTS: Linear variables evidenced a statistically significant drug-induced decrease, whereas nonlinear variables showed significant increases. All changes were highly correlated to drug plasma concentrations. The spatial distribution of the observed connectivity changes clearly differed from a previous study: changes before and after the maximum drug effect were mainly observed over the anterior half of the scalp. Additionally, a new variable with very low computational cost was defined to evaluate nonlinear coupling. This is particularly interesting when all pairs of EEG channels are assessed as in this study. CONCLUSIONS: Results showed that alprazolam induced changes in terms of uncoupling between regions of the scalp, with opposite trends depending on the variables: decrease in linear ones and increase in nonlinear features. Maps provided consistent information about the way brain changed in terms of connectivity being definitely necessary to evaluate separately linear and nonlinear interactions.

Efectos cognitivos del consumo prolongado de alprazolam: el síndrome amnésico / Cognitive effects of the long consumption of alprazolam: the amnesic syndrome

Los efectos adversos por uso inadecuado de benzodiacepinas ocurren frecuentemente pero es algo poco tenido en cuenta. Estudios sobre los efectos del alprazolam en la memoria obtienen diferentes resultados. El objetivo es estudiar las alteraciones de memoria en una mujer (48 años) con consumo prolongado de alprazolam (> 10 años). Se realizó una valoración de capacidades mnésicas (memoria visual, verbal y de trabajo). Lo obtenido nos indica que hay un rendimiento inferior al esperado en todas las áreas de memoria. La participante muestra un perfil de alteración generalizada de las diferentes capacidades de memoria, en contraste con los estudios anteriores que solo muestran alteraciones en una capacidad, un proceso o no muestran afectación. La principal implicación de este estudio es que permite conocer detalladamente las capacidades y los procesos de memoria afectados, de este modo podemos reconocerlos (AU)

The adverse effects for inadequate use of benzodiacepines happen frequently but it is not born in mind. Studies on the effects of the alprazolam in the memory obtain different results. The aim is to study the alterations of memory in a woman (48 years old) with long consumption of alprazolam (over ten years). Was realized an evaluation of memory capacities (visual, verbal and working memory). The obtained in the tests of the memory evaluation indicates us that there is a low performance in all of them. The participant shows a profile of widespread alteration of the different memory capacities, in contrast to the previous studies that only show alterations in a capacity, one process or not show affectation. The principal implication of this study is that allows to know in detail the capacities and processes of memory affected, of this way we can recognize them (AU)

Sources of interindividual variability in IVIVE of clearance: an investigation into the prediction of benzodiazepine clearance using a mechanistic population-based pharmacokinetic model.

Prediction of metabolic clearance in extreme individuals rather than the 'average human' is becoming an attractive tool within the pharmaceutical industry. The current study involved prediction of variability in metabolic clearance for alprazolam, triazolam and midazolam with emphasis on the following factors: first, evaluation of clearance prediction accuracy using intrinsic clearance (CL(int)) data from in vitro metabolic data and back-calculation from in vivo clearance data. Second, the sensitivity of predicted in vivo variability to changes in variability for physiological parameters (e.g. liver weight, haematocrit, CYP3A abundance). Finally, reported estimates of variability in hepatic CYP3A4 abundance (coefficient of variation (CV) 95%) were refined by separating experimental from interindividual variability using a repeat measurement protocol in 52 human liver samples. Using in vitro metabolic data, predicted clearances were within 2-fold of observed for triazolam and midazolam. Clearance of alprazolam was overpredicted by 2.0- to 3.7-fold. Use of in vivo CL(int) values improved prediction of intravenous clearance to within 2-fold of observed for all drugs. Initially, the variability in clearance was overestimated for all drugs (by 1.8- to 3.6-fold). Use of a reduced hepatic CYP3A4 CV of 41%, representative of interindividual variability alone improved predictions of variability in clearance for all drugs to within 2-fold of observed.

Alprazolam as an in vivo probe for studying induction of CYP3A in cynomolgus monkeys.

Induction of the cytochrome P450 (P450) enzyme is a major concern in the drug discovery processes. To predict the clinical significance of enzyme induction, it is helpful to investigate pharmacokinetic alterations of a coadministered drug in a suitable animal model. In this study, we focus on the induction of CYP3A, which is involved in the metabolism of approximately 50% of marketed drugs and is inducible in both the liver and intestine. As a marker substrate for CYP3A activity, alprazolam (APZ) was selected and characterized using recombinant CYP3A enzymes expressed in Escherichia coli. Both human CYP3A4 and its cynomolgus P450 ortholog predominantly catalyzed APZ 4-hydroxylation with sigmoidal kinetics. When administered intravenously and orally to cynomolgus monkeys, APZ had moderate clearance; its first-pass extraction ratio after oral dosing was estimated to be 0.09 in the liver and 0.45 in the intestine. Pretreatment with multiple doses of rifampicin (20 mg/kg p.o. for 5 days), a known CYP3A inducer, significantly decreased plasma concentrations of APZ after intravenous and oral administrations (0.5 mg/kg), and first-pass extraction ratios were increased to 0.39 in the liver and 0.63 in the intestine. The results were comparable to those obtained in clinical drug-drug interaction (DDI) reports related to CYP3A induction, although the rate of recovery of CYP3A activity seemed to be slower than rates estimated in clinical studies. In conclusion, pharmacokinetic studies using APZ as a probe in monkeys may provide useful information regarding the prediction of clinical DDIs due to CYP3A induction.