Injectable Biocatalytic Nanocomposite Hydrogel Factories for Focal Enzyme-Prodrug Cancer Therapy.

Systemic enzyme-prodrug therapy (EPT) using nanofactories, nanoparticles encapsulating prodrug-activating enzymes, is a promising concept for anticancer therapy. However, systemic delivery systems can be problematic. As nanofactories are typically carried by the blood circulation to tissues throughout the body, conversion of anticancer drugs in normal tissues can cause severe side effects. To overcome this problem, we developed a novel focal EPT approach utilizing nanocomposite hydrogels composed of a poly(dl-lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(dl-lactide-co-glycolide) (PLGA-PEG-PLGA) copolymer, LAPONITE, and ß-galactosidase (ß-gal). The nanocomposite gels can be easily injected locally, and the inherent enzyme activity of ß-gal can be preserved long-term. Prodrug 5-FU-ß-gal readily permeated into the interior space of gels and was converted into the active anticancer drug 5-FU. Importantly, a single local injection of nanocomposite gels and prodrug 5-FU-ß-gal provided long-lasting antitumor activity in vivo without observable side effects, demonstrating the potential utility of injectable biocatalytic hydrogel factories for novel focal EPT systems.

Adverse reaction profiles of hemorrhagic adverse reactions caused by direct oral anticoagulants analyzed using the Food and Drug Administration Adverse Event Reporting System (FAERS) database and the Japanese Adverse Drug Event Report (JADER) database.

Direct oral anticoagulants (DOACs) are used in anticoagulant therapy. The purpose of this study was to evaluate the association of DOAC-induced gastrointestinal (GI) and nervous system hemorrhage using the FDA's Adverse Event Reporting System (FAERS) database and the Japanese Adverse Drug Event Report (JADER) database. We identified and analyzed the reports of hemorrhagic reactions between 2004 and 2016 from the FAERS and JADER databases, and calculated the adjusted reported odds ratio (ROR) using the multiple logistic regression method. Additionally, we used the time-to-onset analysis. In the FAERS database, the adjusted ROR of apixaban, rivaroxaban, and dabigatran for GI hemorrhage was 6.79 (5.84-7.91), 19.58 (18.85-20.34), and 14.51 (13.58-15.51), respectively. In the JADER database, the adjusted ROR of apixaban, rivaroxaban, edoxaban, and dabigatran for GI hemorrhage was 11.80 (9.50-14.64), 11.03 (9.18-13.26), 10.17 (6.95-14.88), and 9.85 (7.23-13.42), respectively. We found that the association of GI hemorrhage with DOACs was affected by sex (female). Additionally, 30% of GI hemorrhage was observed after 30 days. Hemorrhagic reactions of both GI and nervous systems were observed in both the spontaneous reporting system databases. We recommend that female patients who experience symptoms related to GI hemorrhage should be closely monitored and advised to adhere to an appropriate care plan. Additionally, our results show that patients should be closely monitored for hemorrhage even after a month.

Evaluation of Drug-Induced Photosensitivity Using the Japanese Adverse Drug Event Report (JADER) Database.

Drug-induced photosensitivity (DIP) refers to the development of cutaneous disorders caused by the combined effects of different medications and light. The aim of this study was to obtain new information on drug risk comparisons and on DIP onset profiles, including seasonal variations, for clinically used prescription drugs. We analyzed reports of DIP recorded in the Japanese Adverse Drug Event Report (JADER) database using a reporting odds ratio (ROR). We also used Weibull proportional-hazards models for each drug to examine the patterns of DIP. The JADER database contains 430587 reports recorded from April 2004 to November 2016. The ROR values (95% confidence interval [CI]) of losartan/hydrochlorothiazide (HCTZ), valsartan/HCTZ, and ketoprofen were 214.5 (162.1-283.9), 104.7 (66.3-165.5), and 117.9 (76.6-181.5), respectively. For time-to-onset analysis, the median durations (interquartile range) for DIP caused by losartan/HCTZ, valsartan/HCTZ, and ketoprofen were 56 (41-78), 49 (38-88), and 8 (2-14) days, respectively. The lower limit of the 95% CI for the Weibull shape parameter ß value for losartan/HCTZ was greater than 1. More than half of the reports of DIP onset following the administration of ketoprofen were recorded within 10 d of treatment initiation. The seasonal variation of photosensitivity reactions was shown to follow an annual sinusoidal pattern with a peak in April and May. Based on the results, losartan/HCTZ, valsartan/HCTZ, and ketoprofen should be used carefully in clinical practice to avoid DIP.

Association between Selective Serotonin Reuptake Inhibitor Therapy and Suicidality: Analysis of U.S. Food and Drug Administration Adverse Event Reporting System Data.

Selective serotonin reuptake inhibitors (SSRIs) are prescribed for the treatment of depression worldwide. SSRIs are suspected to increase the risk of suicidal ideation and behavior (suicidality) in children, adolescents, and young adults. We examined the association between SSRI therapy and suicidality by applying a logistic regression model to age-stratified data from the Food and Drug Administration (FDA) Adverse Event Reporting System database. We attempted to mitigate the effect of patient-related factors by data subsetting. We selected case reports for SSRIs as referred to in the World Health Organization Anatomical Therapeutic Chemical classification code N06AB. The association between SSRIs and "suicidal events" or "self-harm events" was calculated as a reporting odds ratio (ROR) and adjusted for covariates by logistic regression. For subjects <18 years old (y.o.) the adjusted RORs (95% confidence interval) of SSRI therapy with suicidal events were 9.58 (8.97-10.23) in the whole data analysis and 4.64 (4.15-5.19) in the subset analysis; those with self-harm events were 31.40 (27.71-35.58) and 16.31 (13.12-20.29), respectively. Although the adjusted RORs were lower in the subset analyses than in the whole data analyses, both analyses indicated associations between SSRI treatment and suicidal and self-harm events. In both analyses these associations were stronger in the <18 y.o. group than other age groups. Children and adolescents should be closely monitored for the occurrence of suicidality when they are prescribed SSRIs. In addition, we found that data subsetting might mitigate the effect of an intrinsic risk among patients taking the suspected drug.

Analysis of Neuropsychiatric Adverse Events in Patients Treated with Oseltamivir in Spontaneous Adverse Event Reports.

There have been concerns that oseltamivir causes neuropsychiatric adverse events (NPAEs). We analyzed the association of age and gender with NPAEs in patients treated with oseltamivir using a logistic regression model. NPAE data were obtained from the U.S. Food and Drug Administration Adverse Event Reporting System (2004 to 2013). The lower limit of the reporting odds ratio (ROR) 95% confidence interval (CI) of "abnormal behavior" in Japan, Singapore, and Taiwan was ≥1. The effects of the interaction terms for oseltamivir in male patients aged 10-19 years were statistically significant. The adjusted ROR of "abnormal behavior" was 96.4 (95% CI, 77.5-119.9) in male patients aged 10-19 years treated with osletamivir. In female patients, the results of the likelihood ratio test for "abnormal behavior" were not statistically significant. The adjusted NPAE RORs were increased in male and female patients under the age of 20 years. Oseltamivir use could be associated with "abnormal behavior" in males aged 10-19 years. After considering the causality restraints of the current analysis, further epidemiological studies are recommended.

Evaluation of Dabigatran- and Warfarin-Associated Hemorrhagic Events Using the FDA-Adverse Event Reporting System Database Stratified by Age.

Dabigatran and warfarin are oral anticoagulant drugs widely used for the prevention of stroke in patients with atrial fibrillation. The objective of this study was to evaluate the interaction between aging and dabigatran- and warfarin-induced gastrointestinal (GI) and nervous system hemorrhage using data available in the FDA Adverse Event Reporting System (FAERS) database. We analyzed reports of hemorrhagic events in the GI and nervous system recorded in the FAERS database between 2004 and 2014 using an adjusted reporting odds ratio (ROR). We demonstrated that dabigatran-associated GI hemorrhage was significantly increased in patients over the age of 80 years. The RORs of dabigatran increased with increasing age, although aging had little effect on warfarin-associated GI hemorrhage. The ROR for anticoagulant-associated nervous system hemorrhage was not significantly affected by aging, as compared to GI hemorrhage. Our results indicate that the excretion of dabigatran may be affected by aging, as compared to warfarin, likely due to renal function decline. Our results emphasize the need for physicians to closely monitor GI bleeding in aging patients, because it is closely related to renal function deterioration.

Thixotropic ß-Chitin Nanofiber Hydrogel with a Living Body-Responsive Self-Hardening Property and Its Application as a Sprayable Antiadhesion Barrier.

Considering recent advances in surgical techniques, sprayable antiadhesion barriers that are compatible with minimally invasive procedures are needed. However, the relatively low mechanical stiffness of the current thixotropic reversible sol-to-gel transition hydrogels has hindered their medical application. Herein, we show a thixotropic sprayable ß-chitin nanofiber hydrogel that spontaneously lost the thixotropic property in response to the environments within the living body. Furthermore, interactions between hydrogels and the biological environment result in a significant increase in mechanical stiffness. Due to these advantageous properties, ß-chitin nanofiber hydrogels administered by spray prevent postoperative abdominal adhesions and are thus promising sprayable antiadhesion barriers.

Covalent Stem Cell-Combining Injectable Materials with Enhanced Stemness and Controlled Differentiation In Vivo.

Biohybrid materials, which are defined as engineered functional materials combining living components with nonliving synthetic materials, are considered promising bioactive materials for applications in in vivo tissue engineering. However, the rational design of biohybrid materials applicable to in vivo tissue engineering faces major challenges associated with techniques for combining living cells with nonliving synthetic materials and cell sources. Here, we report injectable covalent stem cell-combing biohybrid materials prepared via a bio-orthogonal click cross-linking reaction of azide-modified adipose-derived stem cells (N3[+]ADSCs), one of the most promising cell sources utilized clinically, with alkyne-modified biocompatible alginate polymers. The mechanical properties of the covalent stem cell-combining biohybrid materials can be adapted to the mechanical properties of the surrounding environment in which they are transplanted by alternating the number of N3[+]ADSCs, the concentration of alkyne-modified alginate, and the number of alkyne groups. Importantly, ADSCs in the covalent biohybrid materials expressed a high level of CD-105, a marker for undifferentiated mesenchymal stem cells, in the body in the absence of differentiation signals, whereas very little CD-105 was expressed in the control physical cell-loading materials, demonstrating that this covalent stem cell-combining approach results in enhanced retention of the material's "stemness" and controlled differentiation in the body. We assessed the potential utility of the covalent stem cell-combining biohybrid materials for in vivo tissue engineering using a murine severe skeletal muscle defect-healing model. Importantly, all of the tissues regenerated by the covalent biohybrid material treatment expressed MYH3, a myogenic marker protein, whereas no expression of MYH3 was detected in the tissues reconstructed by treatment with control physical stem cell-loading materials and Matrigel, indicating that this covalent stem cell-combining approach results in controlled differentiation in the body. Our data demonstrate the potential utility of covalent stem cell-combining biohybrid materials with host tissue-integrative and controlled differentiation capabilities available for in vivo tissue engineering.

Angiogenesis Promotion by Combined Administration of DFO and Vein Endothelial Cells Using Injectable, Biodegradable, Nanocomposite Hydrogel Scaffolds.

Desferrioxamine (DFO) upregulates HIF-1α and stimulates expression of vascular endothelial growth factor (VEGF), thereby accelerating neovascularization. As DFO acts primarily upon surrounding vein endothelial cells to stimulate angiogenesis, the angiogenic efficacy of DFO could be reduced in severely injured tissues lacking a sufficient number of vein endothelial cells. We hypothesized that combined administration of DFO and vein endothelial cells is a promising tissue engineering approach for promoting neovascularization. In this study, we evaluated the applicability of this approach using injectable, biocompatible, biodegradable nanocomposite gels consisting of poly(dl-lactide-co-glycolide)-b-polyethylene glycol-b-poly(dl-lactide-co-glycolide) (PLGA-PEG-PLGA) copolymers and clay nanoparticle LAPONITE. The nanocomposites exhibited irreversible thermo-gelation in the presence of DFO, and the mechanical strength was strongly affected by the amount of DFO. The storage moduli of the gels increased with increasing amount of DFO. These results indicate that the interaction between DFO and LAPONITE works as physical cross-linking points and facilitates the formation of the gel network. The nanocomposite gels achieved sustained slow release of DFO due to interactions between DFO and LAPONITE. Human umbilical vein endothelial cells (HUVECs) cultured on DFO-loaded nanocomposite gels exhibited a higher degree of vascular tube formation than cells cultured on nanocomposite gels without DFO. Moreover, the number of branching points and the diameter of the blood vessels regenerated in the gels significantly increased with increasing DFO amount, indicating that DFO released from the gels facilitates vascular tube-forming capacity. As a proof of concept, we demonstrate that the combined administration of DFO and vein endothelial cells using nanocomposite gels promotes greater angiogenesis than DFO administration alone using the same gels by in vivo experiments, confirming the validity of our hypothesis. Considering the multiple advantages of nanocomposite gels with regard to potential vascularization capacity, certain biocompatibility, biodegradability, and injectable cell- and drug-delivery capacity, we concluded that the nanocomposite gels have potential utility as scaffolding biomaterials for vascularization in tissue engineering applications.

Exportin-inspired artificial cell nuclear-exporting nanosystems.

Inspired by the structural and chemical features of naturally occurring importin/exportin that allows them to pass through the nuclear pore complexes, we successfully developed an artificial nuclear-exporting nanosystem capable of eliminating compounds accumulated abnormally in the nucleus.

Biological Tissue-Inspired Living Self-Healing Hydrogels Based on Cadherin-Mediated Specific Cell-Cell Adhesion.

Regarding synthetic self-healing materials, as healing reactions occur at the molecular level, bond formation occurs when healing chemicals are nanometer distances apart. However, motility of healing chemicals in materials is quite limited, permitting only passive diffusion, which reduces the chance of bond formation. By contrast, biological-tissues exhibit significant high-performance self-healing, and cadherin-mediated cell-cell adhesion is a key mechanism in the healing process. This is because cells are capable of a certain level of motility and actively migrate to damage sites, thereby achieving cell-cell adhesion with high efficacy. Here, we report biological-tissue-inspired, self-healing hydrogels in which azide-modified living cells are covalently cross-linked with alkyne-modified alginate polymers via bioorthogonal reactions. As a proof-of-concept, we demonstrate their unique self-healing capabilities originating from cadherin-mediated adhesion between cells incorporated into the gels as mobile healing mechanism. This study provides an example of self-healing material incorporating living components into a synthetic material to promote self-healing.

Neuropsychiatric Adverse Events of Montelukast: An Analysis of Real-World Datasets and drug-gene Interaction Network.

Montelukast is a selective leukotriene receptor antagonist that is widely used to treat bronchial asthma and nasal allergy. To clarify the association between montelukast and neuropsychiatric adverse events (AEs), we evaluated case reports recorded between January 2004 and December 2018 in the Food and Drug Administration Adverse Event Reporting System (FAERS). Furthermore, we elucidated the potential toxicological mechanisms of montelukast-associated neuropsychiatric AEs through functional enrichment analysis of human genes interacting with montelukast. The reporting odds ratios of suicidal ideation and depression in the system organ class of psychiatric disorders were 21.5 (95% confidence interval (CI): 20.3-22.9) and 8.2 (95% CI: 7.8-8.7), respectively. We explored 1,144 human genes that directly or indirectly interact with montelukast. The molecular complex detection (MCODE) plug-in of Cytoscape detected 14 clusters. Functional analysis indicated that several genes were significantly enriched in the biological processes of "neuroactive ligand-receptor interaction." "Mood disorders" and "major depressive disorder" were significant disease terms related to montelukast. Our retrospective analysis based on the FAERS demonstrated a significant association between montelukast and neuropsychiatric AEs. Functional enrichment analysis of montelukast-associated genes related to neuropsychiatric symptoms warrant further research on the underlying pharmacological mechanisms.

A thin hydrogel barrier linked onto cell surface sialic acids through covalent bonds induces cancer cell death in vivo.

Hypersialylation is the aberrant expression of sialic acid in cell surface glycans and is pervasive in cancer cells. Recent studies have shown that hypersialylation provides a microenvironment conducive to cancer progression, mediated by the interaction between sialic acid and sialic acid-binding receptors. Therefore, a technique to block the interaction between the overexpressed sialic acid on cancer cell surfaces and its receptors is a promising approach to develop new cancer therapies. We focused on hydrogels as an artificial barrier to block this interaction and present here the development of a novel technique for selectively covalently binding a thin hydrogel barrier on sialic acid residues on cancer cell surfaces. This technique effectively inhibited cancer cell adhesion, motility and growth, caused cancer cell death in vitro, and completely suppressed tumor growth in vivo, thereby clearly demonstrating a potent antitumor effect.

Alcohol-induced impaired insulin secretion in a Japanese population: 5-year follow up in the Gifu Diabetes Study.

AIMS/INTRODUCTION: Although moderate alcohol consumption lowers the risk of type 2 diabetes in European populations, the same cannot be assumed for Japanese patients with diabetes related to low insulin secretion rather than resistance. We aimed to evaluate the effects of daily alcohol consumption on glucose tolerance and diabetes development risk in Japanese populations. MATERIALS AND METHODS: This retrospective study randomly enrolled 452 men and 659 women aged 40-78 years in 2005 (Gifu, Japan). The participants completed a 75-g oral glucose tolerance test and medical questionnaire. The homeostasis model assessment of insulin resistance, homeostasis model assessment of ß-cell function and insulinogenic index were used to estimate insulin sensitivity and secretion. The relationships between alcohol consumption and these parameters were analyzed using logistic regression after adjusting for potential confounders. The 5-year changes in hemoglobin A1c levels were also evaluated. RESULTS: The adjusted odds ratios for elevated homeostasis model assessment of ß-cell function values (<40%) in the 0-19.9 g/day, 20.0-39.9 g/day and ≥ 40 g/day alcohol consumption groups were 0.98, 1.46 and 2.68, respectively. Alcohol consumption induced a significant decrease in the insulin secretion level among the ≥40 g/day drinkers, especially in men. However, there was no risk of increased insulin resistance based on the homeostasis model assessment of insulin resistance (<2.5) results. The 5-year risk of elevated hemoglobin A1c levels (≥6.5%) was increased according to increase in alcohol consumption in both men and women. CONCLUSIONS: Daily alcohol consumption was associated with reduced insulin secretion and an increased diabetes development risk in Japanese populations.

[Adverse Event Trends Associated with Over-the-counter Combination Cold Remedy: Data Mining of the Japanese Adverse Drug Event Report Database].

OTC combination cold remedies are widely used in Japan. In the present study, we aimed to evaluate the adverse event profiles of OTC combination cold remedy based on the components using the Japanese Adverse Drug Event Report (JADER) database. The JADER database contained 430587 reports between April 2004 and November 2016. 1084 adverse events associated with the use of OTC combination cold remedy were reported. Reporting odds ratio (ROR) was used to detect safety signals. The ROR values for "skin and subcutaneous tissue disorders", "hepatobiliary disorders", and "immune system disorders" stratified by system organ class of the Medical Dictionary for Regulatory Activities (MedDRA) were 9.82 (8.71-11.06), 2.63 (2.25-3.07), and 3.13 (2.63-3.74), respectively. OTC combination cold remedy containing acetaminophen exhibited a significantly higher reporting ratio for "hepatobiliary disorders" than OTC combination cold remedy without acetaminophen. We demonstrated the potential risk of OTC combination cold remedy in a real-life setting. Our results suggested that the monitoring of individuals using OTC combination cold remedy is important.

Contraceptives as possible risk factors for postpartum depression: A retrospective study of the food and drug administration adverse event reporting system, 2004-2015.

Aim: Postpartum depression is a mood disorder that commonly affects women during the early postpartum period. The objective of this study was to analyse the association of postpartum depression with drugs (including contraceptive devices and implants) with spontaneously reported adverse events reported in the US Food and Drug Administration Adverse Event Reporting System database. Design: Retrospective study. Method: Reports of postpartum depression events between 2004-2015 were analysed with a reporting odds ratio (ROR) algorithm. The Medical Dictionary for Regulatory Activities was used to identify postpartum depression. Results: The reporting odds ratios (95% confidence intervals, CI) of levonorgestrel (an intrauterine device with progestogen), etonogestrel (a hormonal contraceptive implant), sertraline and drospirenone (an oral contraceptive) were 12.5 (8.7-18.0), 14.0 (8.5-22.8), 12.2 (6.5-23.1) and 5.4 (2.7-10.9) respectively. Among the drugs in the US Food and Drug Administration Adverse Event Reporting System database, the use of contraceptives or an intrauterine device with progestogen might convey risk for postpartum depression.

Analysis of polypharmacy effects in older patients using Japanese Adverse Drug Event Report database.

Population aging is a global phenomenon, and choosing appropriate medical care for the elderly is critical. Polypharmacy is suspected to increase the risk of adverse events (AEs) in older patients. We examined the AE profiles associated with polypharmacy and aging using the Japanese Adverse Drug Event Report (JADER) database. We attempted to mitigate the effect of patient-related factors using a multiple-logistic regression technique and data subsetting. We selected case reports for AEs as specified in the Medical Dictionary for Regulatory Activities (MedDRA). The association between polypharmacy and "renal disorder" or "hepatic disorder" was evaluated using reporting odds ratio (ROR) and adjusted for covariates using multiple-logistic regression. For renal disorder, advanced polypharmacy showed higher adjusted RORs, because the value of administered drugs group [1.82 (1.76-1.88), ≥ 10] was higher than that of the number of administered drugs group [1.27 (1.24-1.31), 5-9]. The lower limit of the 95% confidence interval (CI) of adjusted ROR for age (≥ 60 years) was > 1 for renal disorder. For hepatic disorder, the adjusted RORs were as follows: 1.17 (1.14-1.20) for the number of administered drugs group (5-9) and 1.14 (1.11-1.18) for the number of administered drugs group (≥ 10). The adjusted RORs of hepatic disorder compared to those of renal disorder had lower adjusted RORs related to the increase in the number of administered drugs. Therefore, elderly individuals should be closely monitored for the occurrence of renal disorder when they are subjected to polypharmacy. This approach might apply to the simultaneous evaluation of the AE risk of polypharmacy and aging.

[Evaluation of the Association of Hand-Foot Syndrome with Anticancer Drugs Using the US Food and Drug Administration Adverse Event Reporting System (FAERS) and Japanese Adverse Drug Event Report (JADER) Databases].

The Japanese Ministry of Health, Labor, and Welfare lists hand-foot syndrome as a serious adverse drug event. Therefore, we evaluated its association with anticancer drug therapy using case reports in the Japanese Adverse Drug Event Report (JADER) and the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS). In addition, we calculated the reporting odds ratio (ROR) of anticancer drugs potentially associated with hand-foot syndrome, and applied the Weibull shape parameter to time-to-event data from JADER. We found that JADER contained 338224 reports from April 2004 to November 2014, while FAERS contained 5821354 reports from January 2004 to June 2014. In JADER, the RORs [95% confidence interval (CI)] of hand-foot syndrome for capecitabine, tegafur-gimeracil-oteracil, fluorouracil, sorafenib, and regorafenib were 63.60 (95%CI, 56.19-71.99), 1.30 (95%CI, 0.89-1.89), 0.48 (95%CI, 0.30-0.77), 26.10 (95%CI, 22.86-29.80), and 133.27 (95%CI, 112.85-157.39), respectively. Adverse event symptoms of hand-foot syndrome were observed with most anticancer drugs, which carry warnings of the propensity to cause these effects in their drug information literature. The time-to-event analysis using the Weibull shape parameter revealed differences in the time-dependency of the adverse events of each drug. Therefore, anticancer drugs should be used carefully in clinical practice, and patients may require careful monitoring for symptoms of hand-foot syndrome.

Time-to-Onset Analysis of Drug-Induced Long QT Syndrome Based on a Spontaneous Reporting System for Adverse Drug Events.

Long QT syndrome (LQTS) is a disorder of the heart's electrical activity that infrequently causes severe ventricular arrhythmias such as a type of ventricular tachycardia called torsade de pointes (TdP) and ventricular fibrillation, which can be fatal. There have been no previous reports on the time-to-onset for LQTS based on data from spontaneous reporting systems. The aim of this study was to assess the time-to-onset of LQTS according to drug treatment. We analyzed the association between 113 drugs in 37 therapeutic categories and LQTS including TdP using data obtained from the Japanese Adverse Drug Event Report database. For signal detection, we used the reporting odds ratio (ROR). Furthermore, we analyzed the time-to-onset data and assessed the hazard type using the Weibull shape parameter. The RORs (95% confidence interval) for bepridil, amiodarone, pilsicainide, nilotinib, disopyramide, arsenic trioxide, clarithromycin, cibenzoline, donepezil, famotidine, sulpiride, and nifekalant were 174.4 (148.6-204.6), 17.3 (14.7-20.4), 52.0 (43.4-62.4), 13.9 (11.5-16.7), 69.3 (55.3-86.8), 54.2 (43.2-68.0), 4.7 (3.8-5.8), 19.9 (15.9-25.0), 8.1 (6.5-10.1), 3.2 (2.5-4.1), 7.1 (5.5-9.2), and 254.8 (168.5-385.4), respectively. The medians and quartiles of time-to-onset for aprindine (oral) and bepridil were 20.0 (11.0-35.8) and 18.0 (6.0-43.0) days, respectively. The lower 95% confidence interval of the shape parameter ß of bepridil was over 1 and the hazard was considered to increase over time.Our study indicated that the pattern of LQTS onset might differ among drugs. Based on these results, careful long-term observation is recommended, especially for specific drugs such as bepridil and aprindine. This information may be useful for the prevention of sudden death following LQTS and for efficient therapeutic planning.