Publications by authors named "O Silpakit"

4 Publications

  • Page 1 of 1

A thai version of mindfulness questionnaire: Srithanya Sati scale.

East Asian Arch Psychiatry 2014 Mar;24(1):23-9

Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.

Objective: To develop a scale for assessing mindfulness named Srithanya Sati Scale (SSS) in Thai context.

Methods: Fourteen items were derived with the help from meditation experts. These were then validated by 16 mental health experts followed by analysis of their psychometric properties. A total of 466 subjects were purposively sampled from various sources. The construct validity of the scale was examined by confirmatory factor analysis. The hierarchical model was applied to test whether 3-factor model of SSS could adequately explain overall mindfulness. Test-retest reliability and the internal consistency of each subscale (awareness, acceptance, and self-recollection) were analysed by Pearson's correlation coefficient and Cronbach's alpha, respectively. Srithanya Stress Test was applied to test the discriminant validity of the questionnaire. The Philadelphia Mindfulness Scale was used for testing the concurrent validity.

Results: The 11-item SSS was found to fit across groups of people with different meditation experiences. Two of the components (awareness and self-recollection) explained the overall mindfulness in beginners. The reliability and other psychometric properties of the scale were highly acceptable.

Conclusion: The SSS may be a reliable, valid, and acceptable tool for measuring mindfulness in the Thai population. Further studies are warranted in people with more experience in meditation, as well as clinical populations.
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March 2014

The impact of dosage of sustained-release formulation on valproate clearance and plasma concentration in psychiatric patients: analysis based on routine therapeutic drug monitoring data.

J Clin Psychopharmacol 2011 Feb;31(1):115-9

Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.

Pharmacokinetic parameters were compared between 2 dosages of valproic acid (VPA) sustained-release (SR) formulation in psychiatric patients. A total of 66 psychiatric patients (21 women and 45 men; age range, 18-60 years) receiving 500 mg/d (n = 28) or 1000 mg/d (n = 38) of VPA SR for at least 4 weeks were recruited into the study. A 5-mL blood sample was collected into a plain tube and immediately centrifuged for plasma. Separation of free VPA was further done using Centrifree micropartition devices. Both total and free VPA concentrations (C(total) and C(free)) were analyzed by TDx analyzer with fluorescence polarization immunoassay technique. The patients' characteristics and pharmacokinetic parameters were compared between the 2 dosage groups using independent t test or χ² test where appropriate. The results show that the increment in C(total) (mg/mL) for every milligram-per-kilogram increment in dosage was decreased from 7 ± 3 to 4 ± 1 (mg/L) / (mg/kg) when the total VPA clearance (CL(total)) increased from 6.1 ± 2.6 to 9.0 ± 3.1 mL/kg per hour with the increasing dose in the 500 mg/d and 1000 mg/d groups, respectively (P < 0.05). The increment in C(free) [0.6 ± 0.3 vs 0.5 ± 0.2 (mg/L) / (mg/kg)] and CL(free) (80.4 ± 41.5 vs 92.2 ± 47.6 ml/kg per hour) were not significantly different. Owing to the saturation of protein binding, percent free VPA was significantly increased from 8 ± 3 to 11 ± 3 when the dose was increased from 500 to 1000 mg/d (P < 0.05). In conclusion, an increase in the VPA dose resulted in a disproportional increase between dosage and C(total), whereas a proportional increase between dosage and C(free) still existed. Therefore, our study suggests that the therapeutic range of C(free) is 4 to 12 mg/L based on the therapeutic range of C(total) (45-100 mg/L) for general psychiatric conditions.
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http://dx.doi.org/10.1097/JCP.0b013e318203b405DOI Listing
February 2011

Chrono impact versus enteric coated valproate in Thai epileptic patients.

J Med Assoc Thai 2005 Nov;88(11):1651-9

Department of Neurology, Prasat Neurological Institute, Bangkok 10400, Thailand.

Background: Since its first clinical use more than 30 years ago, Valproic acid is still being widely prescribed It has been available in Thailand for more than 20 years. Sodium valproate slow-released (SVSR) form has been used in clinical practice in Thailand since 1990. The objectives of this open study were to access the compliance and satisfaction consequences in the epileptic patients.

Material And Method: In this prospective, multi-center study, the authors compared the compliance and satisfaction consequences in epileptic patients switched from more than two times daily sodium valproate enteric-coated tablet (SVEC) regimen to the same total daily dose of SVSR form given once or twice daily.

Results: Eighty-nine of the 100 patients completed the study. 43.8% were male (39 of 89 patients). Mean age was 34.74 +/- 12.67 years. Most common etiology of epilepsy was idiopathic 40.4%. Patients were very/fairly happy with the SVSR form 94.4% compared to the SVEC form 56.2% (p = 0.000). Patients had been experiencing no problem with the SVSR form 67.4% compared to SVEC form 38.2% (p = 0.000) and also never missing taking SVSR. form 77.5% compared to SVEC form 40.4% (p = 0.000). According to convenience, patients preferred to administer SVSR form once a day 92.1% and never over taking dosed the antiepileptic drug 96.6%. SVSR form had fewer side effects than the enteric-coated form interms of memory problem (40.4% vs 48.3%) (p = 0.000), sleepiness (30.3% vs 42.7%) (p = 0.041) and difficulty in thinking clearly (38.2% vs 44.9%) (p = 0.001). The patients were seizure free during the study period comparing SVSR form 76.4% to SVEC form 65.2% (p = 0.011).

Conclusion: Patients preferred once daily regime. Switching from SVEC to SVSR form increased seizure free, reduced side effects, improved patient's compliance and satisfaction.
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November 2005

Comparative study of bioavailability and clinical efficacy of carbamazepine in epileptic patients.

Ann Pharmacother 1997 May;31(5):548-52

Division of Neurology, Srithanya Hospital, Nonthaburi, Thailand.

Objective: To compare the bioavailability of three generic brands of carbamazepine tablets with that of a proprietary brand in adult patients with epilepsy.

Design: A double-blind, randomized, three-phase crossover study.

Setting: A psychiatric facility.

Participants: Eighteen patients with epilepsy who had taken carbamazepine at least 5 months before entering the study.

Main Outcome Measures: Ten blood specimens from each patient were collected at steady-state. Plasma concentration of carbamazepine was analyzed for pharmacokinetic parameters such as maximum plasma concentration (Cmax), mean time to reach maximum concentration (tmax), and mean AUC.

Results: There were no statistically significant differences in these parameters among four brands of carbamazepine. However, when comparing the 90% CI of AUC of three generic brands with that of the proprietary brand, the AUC of two generic brands lay within a range of 80% to 120%. The effects of gender and each brand of carbamazepine on these pharmacokinetic parameters were also analyzed. Breakthrough seizures occurred even though the plasma concentration of carbamazepine was therapeutic.

Conclusions: The bioavailability of two generic brands of carbamazepine tablets (Carmapine and Carzepine) and the proprietary brand (Tegretol) were equivalent in this sample of adult patients with epilepsy.
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http://dx.doi.org/10.1177/106002809703100504DOI Listing
May 1997
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