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Abstract: What is already known about this subject • Schisandra sphenanthera extract (SchE) and tacrolimus are often co-administrated in treating renal and liver transplant recipients in China. • We discovered occasionally that blood tacrolimus concentrations are markedly increased in some patients who receive tacrolimus and concomitant SchE. • This is the first study to investigate the effects of SchE on the pharmacokinetics of tacrolimus. What this study adds • Following administration of SchE in healthy volunteers, the mean AUC, AUMC and Cmax of tacrolimus substantially increases, whereas its CL/F and V/F decreases significantly. • Blood tacrolimus concentrations need to be closely monitored and dose adjustments of tacrolimus have to be made accordingly in the presence of SchE. Aim To assess the effect of Schisandra sphenanthera extract (SchE) on the pharmacokinetics of tacrolimus in healthy volunteers. Methods Twelve healthy male volunteers were orally treated with SchE, three capsules twice daily for 13 days. Pharmacokinetic investigations of oral tacrolimus administration at 2 mg were performed both before and at the end of the SchE treatment period. Whole blood tacrolimus concentrations were determined by enzyme-linked immunosorbent assay. Estimated pharmacokinetic parameters before and with SchE were calculated with noncompartmental techniques. Results Following administration of SchE, the average percentage increases of individual increases in AUC, AUMC and Cmax of tacrolimus were 164.2% [95% confidence interval (CI) 70.1, 258.4], 133.1% (95% CI 49.5, 261.3) and 227.1% (95% CI 155.8, 298.4), respectively (P < 0.01 or 0.05). On average, there was a 36.8% (95% CI 13.4, 60.2) increase in tacrolimus tmax (P < 0.01). The average percentage decreases in CL/F and V/F were 49.0% (95% CI 31.1, 66.9) and 53.7% (95% CI 40.1, 67.4), respectively (P < 0.01). Conclusions SchE can increase the oral bioavailability of tacrolimus. The results of this study will add important information to the interaction area between drugs and herbal products.

Abstract: Objective: To estimate the prevalence of, and factors associated with, abnormal serum cholinesterase (SChE) levels among chilli-farm workers in Chatturat District, Chaiyaphum Province. Methods: A total of 350 chilli-farm workers aged 18-60 yr were randomly sampled and interviewed. A reactive-paper finger-blood test was used to assess SChE levels. Results: The prevalence of abnormal SChE levels was 32.0%. The most common pesticide-related symptoms were dizziness (38.0%), headache (30.9%), nausea/vomiting (26.9%), and fever (26.9%). Multiple logistic regression analysis revealed 7 factors were independently associated with abnormal SChE level: male gender, single/separated/divorced, being a permanent worker, spraying pesticide more than 3 times per month, having moderate or poor pesticide-use behaviors, and low perceived susceptibility and severity of pesticide use. Conclusions: The prevalence of abnormal SChE levels among chilli-farm workers was quite high. It would be beneficial to decrease pesticide use and encourage alternative measures. Effective preventive interventions to increase correct perceptions of pesticide use, the use of personal protective measures and continuing monitoring for blood cholinesterase, especially for male permanent farm workers, are recommended.

Abstract: Acute organophosphate poisoning (OPP) such as dichlorvos may be monitored by the measurement of the erythrocyte acetyl cholinesterase (EAChE) and the serum cholinesterase (SChE) activities. The aim of this study was to look at correlation between the severity of the OPP judged by certain parameters such as coma, hemodynamic disturbances, respiratory failure, and the decrease of cholinesterases enzymes including EAChE and SChE at admission. Cholinesterase activity was determined upon admission and then on days 3 and 15 in the morning. Clinical effects, EAChE, and SChE activities data were investigated in 42 patients with OPP aged of 29.6 ± 11.8 years with acute cholinergic crisis in all cases. They were comatose in 29% of cases, presenting both hypotension or shock and hypoxemia in 17% of cases. Fifteen of them (36%) required mechanical ventilation. The mean EAChE activity at admission was 24.3 ± 11.6 μ mol/mL per hour at 37 °C; it was 1260 ± 2204 IU/L for SChE. There were no correlations between the EAChE and the SChE activities. The EAChE was decreased only in comatose patients and those presenting hypotension, hypoxemia, and bradycardia with a cutoff of 23.5 μ mol/mL per hour at 37 °C. Death was observed in 2 patients with a deep decrease of the EAChE at 5 μ mol/mL per hour at 37 °C in 1 case and 9 μ mol/mL per hour at 37 °C in another. The kinetics of improvement of the EAChE activity below the cutoff showed the absence of statistical improvement of the EAChE activity on day 3 (16.6 ± 9 vs 19.5 ± 5.7 μ mol/mL per hour at 37 °C); this improvement was remarkable on day 15 (16.6 ± 9 vs 27.5 ± 6.5 μ mol/mL per hour at 37 °C, P = .0004). In summary, the marked decrease of EAChE activity appears in this study as prognostic factor in acute OPP, and coma, respiratory failure, hemodynamic disturbances, and death are associated with a decrease of the EAChE of less than 23.5 μ mol/mL per hour at 37 °C.