The deleterious effects of sofosbuvir and ribavirin (antiviral drugs against hepatitis C virus) on different body systems in male albino rats regarding reproductive, hematological, biochemical, hepatic, and renal profiles and histopathological changes.

Sofosbuvir is one of the crucial drugs used in the treatment of chronic hepatitis C virus (HCV) in adults and children with compensated liver disease, including cirrhosis. It may be used alone or with other drugs. Ribavirin is an antiviral medication used to treat HCV infection. It is not effective when used alone and must be used in combination with other medications, such as sofosbuvir. This study pertains to a comprehensive assessment of the deleterious effects of sofosbuvir (an antiviral drug against chronic HCV) or sofosbuvir combined with ribavirin (an antiviral drug against RNA and DNA viruses) on several biological activities of the body, including hematological, hormonal, biochemical, histological, and immunohistochemical examinations during a long-standing period on male healthy rats. In addition, fertility assessments were performed, including sperm collections and semen parameter investigations. This study was conducted on 21 male rats divided into three equal groups. Group I (control group) received distilled water; group II (sofosbuvir group) received sofosbuvir (4 mg/kg); and group III (sofosbuvir + ribavirin) received sofosbuvir (4 mg/kg) plus ribavirin (30 ml/kg). All groups received the specific drug for six months. Blood and tissue samples were collected for hematological, hormonal, biochemical, histological, and immunohistochemical examinations. In addition, sperm collection and assessments of semen parameters were performed. Results revealed that sofosbuvir causes a highly significant decrease in the mean of most hematological, immunological, hormonal, and biochemical parameters, except for a few numbers of parameters such as neutrophils, monocytes, basophils, cortisol, GOT, and lipase, which exhibit a significant increase. The same occurred in the sofosbuvir + ribavirin group, but at much higher levels, as most hematological, immunological, hormonal, and biochemical parameters exhibit a highly significant decrease except for monocytes, triglyceride, and lipase, which exhibit a significant increase. When compared to the sofosbuvir group alone, the sofosbuvir + ribavirin group demonstrated a highly significant decline in the mean of most hematological, immunological, hormonal, and biochemical parameters except lymphocytes and triglycerides, which exhibit a substantial increase. For the reproductive parameters, both groups exhibit a significant decrease in the total sperm motility percentage. Finally, it can be concluded that sofosbuvir causes acute pancreatitis and combined immunodeficiency. Ribavirin is associated with hormonal deficiency, which indicates the occurrence of hypopituitarism. Moreover, sofosbuvir and ribavirin synergistically affect myelosuppression and cause iron-deficiency anemia. However, sofosbuvir, or its combination with ribavirin, is associated with a reduced risk of hepatocellular carcinoma. Besides, adding ribavirin to be combined with sofosbuvir improved the immunodeficiency caused by sofosbuvir; this confirms that using ribavirin with sofosbuvir reduces the side effects of both alone.

Clinical Pharmacokinetics and Pharmacodynamics of Voclosporin.

Voclosporin is an approved option for the long-term treatment of lupus nephritis. We aimed to provide a narrative review of the pharmacokinetics and pharmacodynamics of voclosporin. In addition, we derived values for pharmacokinetic and pharmacodynamic parameters by graphical analysis of published diagrams. Compared with cyclosporin, low-dose voclosporin is associated with a lower nephrotoxicity risk and, compared to tacrolimus, with a lower diabetes risk. After repetitive dosing of 23.7 mg twice daily and at target trough concentrations of 10-20 ng/mL, the dominant or effect-indicative half-life is estimated at 7 hours. Compared with the pharmacodynamics of cyclosporin, the potency of voclosporin is stronger, with a lower concentration CE50 of 50 ng/mL already producing the half-maximum immunosuppressive effect. The Hill coefficient can be predicted to be low at H = 1.3, indicating a concentration-dependent effect on the immune system. The corresponding effect bisection time of 10 hours allows for dosing every 12 hours. Accordingly, the trough concentration will be above the threshold concentration that produces 5% of the maximum effect of 5.2 ng/mL for immunosuppression but below both the predicted threshold of 30 ng/mL for nephrotoxicity and the predicted threshold of 40 ng/mL for new-onset diabetes. The pharmacokinetic and pharmacodynamic properties suggest the use of low-dose voclosporin combined with mycophenolate and low-dose glucocorticoids for immunosuppressive maintenance therapy.

Arrhythmias related to antipsychotics and antidepressants: an analysis of the summaries of product characteristics of original products approved in Germany.

PURPOSE: Most psychiatric drugs, such as antidepressants (AD) and antipsychotics (AP), may cause cardiac adverse events (CAE). We used summaries of product characteristics (SmPC) for assessing the likelihood of AD and AP to cause CAE. METHODS: We identified all original medicinal products (OMP) of AD and AP approved in Germany. We searched for their SmPCs using the online services of PharmaNet.Bund, Gelbe liste®, Rote Liste®, Fachinfo-Service®, and via manufacturer contact. We extracted frequencies of reported CAE (QT prolongation, Torsade de Pointes tachycardia, and ventricular arrhythmia) and performed a risk assessment. RESULTS: We obtained the SmPCs of 24 AD and 26 AP identified as OMP. Comparably high reported frequencies regarding QT prolongation were found for Invega® (paliperidone), Serdolect® (sertindole) (≥ 1/100 and < 1/10), and Zoloft® (sertraline) (≥ 1/10.000 and < 1/1000); regarding Torsade de Pointes tachycardia were found for Serdolect® (≥ 1/1000 to < 1/100), Zoloft®, and Trevilor® (venlafaxine) (≥ 1/10.000 and < 1/1000); regarding ventricular tachycardia for Solian® (amisulpride), Xomolix® (droperidol), Zyprexa® (olanzapine), and Trevilor® (≥ 1/10.000 and < 1/1000). CONCLUSION: The risk and frequency of CAE, as reported in the SmPCs, varied significantly among substances and between groups. There are more reports for AP than AD. The AP with the most frequently reported CAE (QT prolongation and Torsade de Pointes tachycardia) was Serdolect®; for AD, Zoloft® (QT prolongation, Torsade de Pointes tachycardia) and Trevilor® (Torsade de Pointes tachycardia and ventricular tachycardia) carried a higher cardiac risk.

The Impact of CYP3A4*22 on Tacrolimus Pharmacokinetics and Outcome in Clinical Practice at a Single Kidney Transplant Center.

Background: Although there is evidence that the CYP3A4*22 variant should be considered in tacrolimus dosing in renal transplantation, its impact beyond tacrolimus dose requirements remains controversial. Methods: In a cohort of 121 kidney transplant recipients, we analyzed the CYP3A4*1B, CYP3A4*22, and CYP3A5*3 alleles and the ABCB1 variants 1236C>T, 2677G>T/A, and 3435C>T for their impact on exposure and dose requirement. Relevant clinical outcome measures such as acute rejection within the first year after transplantation, delayed graft function, and renal function at discharge (estimated glomerular filtration rate) were evaluated. Results: Extensive metabolizer (n = 17, CYP3A4*1/*1 carriers with at least one CYP3A5*1 allele) showed significantly higher tacrolimus dose requirement (P = 0.004) compared with both intermediate metabolizer (IM, n = 93, CYP3A5*3/*3 plus CYP3A4*1/*1 or CYP3A4*22 carriers plus one CYP3A5*1 allele), and poor metabolizer (n = 11, CYP3A4*22 allele in combination with CYP3A5*3/*3) after onset of therapy. Significantly higher dose requirement was observed in CYP3A5 expressers (P = 0.046) compared with non-expressers again at onset of therapy. Using the log additive genetic model, the area under the curve for the total observation period up to 16 days was significantly associated with the CYP3A5*3 genotype (P = 3.34 × 10-4) as well as with the IM or extensive metabolizer phenotype (P = 1.54 × 10-4), even after adjustment for multiple testing. Heterozygous carriers for CYP3A4*22 showed significantly higher areas under the curve than the CYP3A4*1/*1 genotype in the second week post-transplantation (adjusted P = 0.016). Regarding clinical outcomes, acute rejection was significantly associated with human leukocyte antigen mismatch (≥3 alleles; OR = 12.14, 95% CI 1.76, 525.21, P = 0.019 after correction for multiple testing). Graft recipients from deceased donors showed higher incidende of delayed graft function (OR 7.15, 95% CI 2.23, 30.46, adjusted P = 0.0008) and a lower estimated glomerular filtration rate at discharge (P = 0.0001). Tested CYP3A4 or CYP3A5 variants did not show any effects on clinical outcome parameters. ABCB1 variants did neither impact on pharmacokinetics nor on clinical endpoints. Conclusion: At our transplantation center, both CYP3A5*3 and, to a lesser extent, CYP3A4*22 affect tacrolimus pharmacokinetics early after onset of therapy with consequences for steady-state treatment in routine clinical practice.

Comparative Protective Effects of N-Acetylcysteine, N-Acetyl Methionine, and N-Acetyl Glucosamine against Paracetamol and Phenacetin Therapeutic Doses-Induced Hepatotoxicity in Rats.

BACKGROUND AND AIMS: Both paracetamol (PA) and phenacetin (PH) are analgesic and antipyretic agents. Part of phenacetin therapeutic activity is attributed to its metabolism into paracetamol. Paracetamol causes direct hepatic oxidative stress damage. The present study aimed to investigate the possible damaging effects of both PA and PH, when used in therapeutic doses, on rat liver and to compare the antioxidant and hepatoprotective effects of N-acetylcysteine (NAC), N-acetyl-methionine (NAM), and N-acetylglucosamine (NAG) against PA- or PH-induced hepatic damage. METHODS: 90 male Wistar albino rats (120-140 gm) were undertaken, categorized randomly into 9 groups of 10 rats each, and administered by gavage for 2 weeks with DMSO 1% (controls), PA, PA+NAC, PA+NAM, PA+NAG, PH, PH+NAC, PH+NAM, and PH+NAG. Biochemical assays of malondialdehyde (MDA), nitric oxide (NO), reduced glutathione (GSH), total thiols, and alpha-fetoprotein (AFP) in liver homogenates and serum assays of ALT, AST, 8-hydroxy guanine (8-OH-Gua), and AFP were done. Also histopathological examinations of liver tissues in various groups were done. RESULTS: PA and PH cause significant increase in hepatic levels of MDA, NO, and AFP and serum ALT, AST, and 8-OH-Gua levels, with significant decrease in hepatic GSH and total thiols. NAG and NAC significantly improve the PA- and PH-induced hepatic and blood, biochemical, and histopathological disturbances, respectively. CONCLUSIONS: Both PA and PH induce oxidative stress in rat liver within their therapeutic doses. NAG and NAC in pharmacological doses can antagonize the oxidative damaging effect of both PA and PH.

Analytical Validation and Cross-Validation of an NFAT-Regulated Gene Expression Assay for Pharmacodynamic Monitoring of Therapy With Calcineurin Inhibitors.

BACKGROUND: Analysis of residual gene expression of the nuclear factor of activated T cell (NFAT)-regulated genes has been developed as a pharmacodynamic biomarker to monitor therapy with calcineurin inhibitors. The availability of commercial primer sets (Search-LC) and the well-established assay protocol makes this biomarker a promising candidate to be used clinically in different laboratories. However, implementation of the method in routine practice requires analytical robustness and comparable results across laboratories. Therefore, a protocol originally established at the Institute of Immunology, Heidelberg was verified at the Institute of Laboratory Medicine, Klinikum Stuttgart, and a comparison study was conducted between the 2 laboratories. METHODS: For the analytical verification, whole blood samples of healthy individuals were incubated with tacrolimus in vitro. Linearity, imprecision, and limit of quantification, as well as sample stability, were investigated. For interlaboratory comparison, samples of patients under cyclosporine A therapy were analyzed in Heidelberg and then reanalyzed in Stuttgart within 24 hours. RESULTS: Tacrolimus (6.25-50 mcg/L) decreased the expression of NFAT-regulated genes in vitro dose dependently (15%-89%). Within- and between-assay coefficient of variations (n = 6 each) were <17%. The limit of quantification was <200 cDNA copies for each of the interleukin-2, interferon-γ, and granulocyte-macrophage colony-stimulating factor genes. Samples were stable for 24 hours. Interlaboratory comparison using patient samples correlated well (r = 0.951) but showed an inconsistent bias depending on the magnitude of residual gene expression. CONCLUSIONS: The assay can be set up with a satisfactory analytical performance in a routine molecular biological laboratory and shows comparable results between laboratories. The reproducibility of the NFAT-regulated gene expression assay across laboratories can facilitate the implementation of this assay for pharmacodynamic routine monitoring of calcineurin inhibitors in different centers.

Performance of a phosphoflow assay to determine phosphorylation of S6 ribosomal protein as a pharmacodynamic read out for mTOR inhibition.

OBJECTIVES: The S6 ribosomal protein (S6RP) is phosphorylated by the mammalian target of rapamycin (mTOR). The objective of this study was to assess the analytical suitability of a commercial kit-based phosphoflow cytometry protocol using whole blood (WBS) to measure the level of phosphorylated S6RP (p-S6RP) in T-cell subsets to study the pharmacodynamic effects of mTOR inhibitors (mTORi). DESIGN AND METHODS: A kit was used for fixation and permeabilization of mitogen-stimulated cells, and p-S6RP was assessed separately in CD3+CD4+ and CD3+CD8+ cells by employing an anti-phospho-Ser235/236 antibody. Specificity, linearity, within-run precision and stability were investigated in either WBS spiked with everolimus and non-mTORi immunosuppressants or in WBS from patients on immunosuppressive therapy (n=56). In addition, healthy controls (n=10) and patients without immunosuppression (n=10) were included. A comparison (n=15) with an established western blot method based on anti-phospho p70S6 kinase (Thr389) was made by splitting WBS. RESULTS: Everolimus decreased p-S6RP in vitro concentration dependently (0.00-27.4µg/L). This effect was also confirmed in vivo after a single dose of everolimus to healthy volunteers (n=3). However, spiking WBS with 500µg/L cyclosporine also decreased p-S6RP. The within-run coefficient of variation was <18% in transplant patients and <27% in healthy controls for both cell subsets. Sample stability for p-S6RP analysis was limited (<24h). p-S6RP was significantly decreased in CD3+CD8+ cells of patients treated with sirolimus (p=0.02) but not with everolimus. No significant correlation between the phosphoflow- and western blot method was noted. CONCLUSION: The phosphoflow assay of p-S6RP performed well analytically, but sample stability, specificity, and method comparison results question its fitness for clinical purposes.