[Issuance of Recommendation Entitled "Profession and Lifelong Learning of Pharmacists Responsible for Sustainable Medical Care" by Science Council of Japan and Subsequent Response].

In order to provide sustainable medical care in a super-aging society, pharmacists are required to play a role in integrated community care systems in cooperation with multiple professionals, in addition to prescription-based dispensing. We propose the necessity of building an interprofessional information sharing system, lifelong training for pharmacists, and the establishment of a professional certification system.

First phase 1 clinical study of olaparib in pediatric patients with refractory solid tumors.

BACKGROUND: The survival of patients with high-risk, refractory, relapsed, or metastatic solid tumors remains dismal. A poly(ADP-ribose) polymerase (PARP) inhibitor could be effective for the treatment of pediatric solid tumors with defective homologous recombination. METHODS: This open-label, multicenter phase 1 clinical trial evaluated the safety, tolerability, and efficacy of olaparib, a PARP inhibitor, in pediatric patients with refractory solid tumors to recommend a dose for Phase 2 trials. Olaparib (62.5, 125, and 187.5 mg/m2 twice daily) was administered orally every day (1 cycle = 28 days) using a standard 3 + 3 dose-escalation design. Patients aged 3-18 years with recurrent pediatric solid tumors were eligible. Pharmacokinetic and pharmacodynamic analyses were performed. RESULTS: Fifteen patients were enrolled and received olaparib monotherapy, which was well tolerated. The recommended phase 2 dose for daily administration was 187.5 mg/m2 twice daily. Pharmacokinetics were dose proportional. The area under the concentration-time curve from 0 to 12 h and the peak plasma concentration for 187.5 mg/m2 twice daily in children were comparable to previous data obtained in a 200-mg, twice-daily cohort and lower than those in the 300-mg twice-daily cohort in adults. Pharmacodynamic studies demonstrated substantial inhibition of PARP activity. Two partial responses were observed in patients with Wilms tumor and neuroblastoma. CONCLUSIONS: This report is the first clinical trial to describe the use of a PARP inhibitor as monotherapy in children. Olaparib was well tolerated, with preliminary antitumor responses observed in DNA damage response-defective pediatric tumors. LAY SUMMARY: This Phase 1 trial evaluated the efficacy and safety of olaparib in patients with refractory childhood solid tumors. Olaparib was well tolerated, achieving objective response in 2/15 patients. The DNA damage response was attenuated in nearly one-half of advanced neuroblastoma patients, demonstrating the utility of the PARP inhibitor. The results support further investigation of olaparib as a new treatment for DNA damage-response or repair-defective pediatric cancers.

Hematopoietic Cell Transplantation with Reduced Intensity Conditioning Using Fludarabine/Busulfan or Fludarabine/Melphalan for Primary Immunodeficiency Diseases.

PURPOSE: The purpose of our study was to compare the safety and efficacy of hematopoietic cell transplantation (HCT) using fludarabine (Flu)-based reduced intensity conditioning (RIC) with busulfan (BU) or melphalan (Mel) for primary immunodeficiency diseases (PID). METHODS: We retrospectively analyzed transplant outcome, including engraftment, chimerism, immune reconstitution, and complications in 15 patients with severe combined immunodeficiency (SCID) and 27 patients with non-SCID PID. The patients underwent Flu-based RIC-HCT with BU (FluBU: 7 SCID, 16 non-SCID) or Mel (FluMel: 8 SCID, 11 non-SCID). The targeted low-dose BU with therapeutic drug monitoring was set to 30 mg hour/L for SCID. RESULTS: The 2-year overall survival of all patients was 79.6% and that of patients with SCID in the FluBU and FluMel groups was 100% and 62.5%, respectively. In the FluBU group, all seven patients achieved engraftment, good immune reconstitution, and long-term survival. All five patients receiving umbilical cord blood transplantation achieved complete or high-level mixed chimerism and sufficient specific IgG production. In the FluMel group, six of eight patients achieved complete or high-level mixed chimerism. Viral reactivation or new viral infection occurred in one FluBU group patient and four FluMel group patients. In the non-SCID group, 10 of 11 patients (91%) who received FluMel achieved complete or high-level mixed chimerism but had variable outcomes. Patients with WAS (2/2 patients), NEMO deficiency (2/2 patients), and X-linked hyper IgM syndrome (2/3 patients) who received FluBU achieved complete or high-level mixed chimerism and long-term survival. CONCLUSIONS: RIC-HCT with FluBU is a safe and effective strategy for obtaining high-level donor chimerism, immune reconstitution including B cell function, and long-term survival in patients with SCID. In patients with non-SCID PID, the results varied according to the subtype of the disease. Further prospective studies are required to optimize the conditioning regimen for non-SCID PID.

Population pharmacokinetics of cefazolin before, during and after cardiopulmonary bypass in adult patients undergoing cardiac surgery.

PURPOSE: The aims of the present study were to establish a population pharmacokinetic (PPK) model of cefazolin for adult patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) and to assess the probability of target attainment (PTA) for the prophylaxis of surgical site infection (SSI) using cefazolin. METHODS: Adult patients who underwent cardiac surgery with CPB were enrolled in the prospective study. Blood samples for plasma cefazolin assay were collected, and total and unbound drug concentrations were measured and analysed using the nonlinear mixed-effects modelling (NONMEM) software considering saturable plasma protein binding. Using the PPK model, plasma unbound cefazolin concentration-time courses with current prophylaxis protocols were simulated, and the PTA for common SSI pathogens was estimated. RESULTS: A total of 199 blood samples were obtained from 27 patients. A one-compartment model with first-order elimination plus an on/off CPB compartment best described the data. The population mean for systemic drug clearance (CL) was reduced and that for the volume of distribution (V) was increased during CPB compared with the pre-CPB values. CPB-induced hypoalbuminemia was associated with reduced maximum protein binding (Bmax). The simulation studies suggested that the current dosing protocols are insufficient for attaining PTA > 0.9 throughout surgery against pathogens with minimum inhibitory concentrations (MICs) >8 mg/L. A new dosing protocol that achieves a PTA > 0.9 for pathogens with a MIC of 16 mg/L was proposed. CONCLUSION: PPK modelling with simulation may be valuable for devising a cefazolin prophylaxis protocol for patients undergoing cardiac surgery with CPB.

[Present and Future of the Japanese Pharmacopoeia in the Clinical Setting and Pharmacy Education].

The Japanese Pharmacopoeia (JP) has played a major role in ensuring the quality of drugs used in Japan as the ultimate source of information on pharmaceuticals. Physicians and pharmacists can reliably use drugs in the clinical setting because they trust the quality when medical treatment progresses smoothly. When there is a problem or challenge, they can refer to the JP. For pharmacists, both the quality of the drug and information on its efficacy and safety are indispensable. Twelve years have passed since the introduction of a 6-year course in pharmacy education, but the weight placed upon the JP has not increased in the educational curriculum. A specific behavioral objective of describing the significance and structure of the JP is included in the revised model core curriculum for pharmacy education. However, fewer than 60% of pharmacy schools have courses specifically focusing on the JP. Professors of physical chemistry, analytical chemistry, pharmaceutics, and pharmacognosy often teach the relevant sections of the JP in their lectures. The foundations of the Japanese manufacturing industry have been questioned because data falsification and inspection fraud have been disclosed in numerous fields. Therefore, ethical education for those who use the JP is a prerequisite for ensuring the reliability of pharmaceuticals.

Phase I clinical study of oral olaparib in pediatric patients with refractory solid tumors: study protocol.

BACKGROUND: There is no established standard chemotherapy for recurrent pediatric solid tumors such as neuroblastoma and sarcoma. Since some of these tumor cells show dysfunctions in homologous recombination repair, the goal is to conduct a phase I study of olaparib, a poly(ADP-ribose) polymerase inhibitor. In this clinical trial, the aims are to evaluate the safety, tolerability, and efficacy of olaparib in pediatric patients with refractory solid tumors and to recommend a dose for phase II trials. METHODS: In this open-label, multicenter study, olaparib tablets (62.5, 125, and 187.5 mg/m2 b.i.d.) will be administered orally in a standard 3 + 3 dose escalation design. Patients aged 3 to 18 years with recurrent pediatric solid tumors are eligible. Pharmacokinetic and pharmacodynamic analyses will also be performed. DISCUSSION: This study aims to extend the indications for olaparib by assessing its safety and efficacy in pediatric refractory solid tumor patients. TRIAL REGISTRATION: UMIN-CTR ( UMIN000025521 ); Registered on January 4, 2017.

Effects of cardiopulmonary bypass on the disposition of cefazolin in patients undergoing cardiothoracic surgery.

The aim of the study was to evaluate the disposition of plasma unbound cefazolin in patients undergoing cardiothoracic surgery with cardiopulmonary bypass (CPB). Adult patients undergoing cardiothoracic surgery with CPB were enrolled in the study. Cefazolin sodium was given intravenously before skin incision (1 g) and at the beginning of CPB (2 g). Thereafter, an additional dose (1 g) was given every 4 hours. Seven to ten blood samples were collected before and during surgery. Plasma total and unbound (ultrafiltrated) cefazolin concentrations were analyzed using an HPLC-UV method. Plasma protein binding was analyzed with the Langmuir model. Twenty-seven patients (aged 70 ± 12 years, body weight 62 ± 12 kg, mean ± SD) with GFR >30 mL min-1 completed the study. There was a significant (P < 0.001) increase in median plasma unbound fraction of cefazolin from 21% before skin incision to 45% during CPB (P < 0.001), which was accompanied by a significant (P < 0.001) reduction in median plasma albumin concentration from 36 to 27 g L-1. Plasma concentrations of unbound cefazolin exceeded the assumed target thresholds of 2 µg mL-1 in all samples and of 8 µg mL-1 in all but one of 199 samples. The increased plasma unbound fraction of cefazolin would be attributable to dilutional reduction of serum albumin at the beginning of CPB and to saturable plasma protein binding of cefazolin. These data reveal CPB may alter the plasma protein binding and possibly distribution of cefazolin. Further studies are warranted to reappraise the protocol of antimicrobial prophylaxis with cefazolin in patients undergoing surgery with CPB.

Clozapine-Induced Acute Hyperglycemia Is Accompanied with Elevated Serum Concentrations of Adrenaline and Glucagon in Rats.

Clozapine, an atypical antipsychotic agent, has been reported to cause acute hyperglycemia. However, the mechanism of clozapine-induced rapidly developing hyperglycemia is not well elucidated. To clarify the mechanism underlying clozapine-induced acute hyperglycemia, we investigated the effects of single intravenous administration of clozapine on the serum concentrations of glucose and several endogenous substances in rats. Male Wistar rats received an intravenous injection of saline (control) or clozapine 2.5, 5, 10 mg/kg. Blood samples were obtained periodically after clozapine administration to determine the serum concentrations of glucose, adrenaline, glucagon, insulin, corticosterone, and clozapine. The serum concentrations of glucose, adrenaline, and glucagon increased dose-dependently after the administration of clozapine at 2.5-10 mg/kg, and reached maxima at 5 mg/kg of clozapine. The serum concentration of corticosterone increased after the administration of clozapine, but no significant variation was observed with the dosage of clozapine. The concentration of serum insulin increased in a dose-dependent manner after clozapine administration. In conclusion, a single administration of clozapine increased the serum concentration of glucose in rats, and adrenaline and/or glucagon would be associated with clozapine-induced acute hyperglycemia.

Association of schizophrenia onset age and white matter integrity with treatment effect of D-cycloserine: a randomized placebo-controlled double-blind crossover study.

BACKGROUND: It has been reported that drugs which promote the N-Methyl-D-aspartate-type glutamate receptor function by stimulating the glycine modulatory site in the receptor improve negative symptoms and cognitive dysfunction in schizophrenia patients being treated with antipsychotic drugs. METHODS: We performed a placebo-controlled double-blind crossover study involving 41 schizophrenia patients in which D-cycloserine 50 mg/day was added-on, and the influence of the onset age and association with white matter integrity on MR diffusion tensor imaging were investigated for the first time. The patients were evaluated using the Positive and Negative Syndrome Scale (PANSS), Scale for the Assessment of Negative Symptoms (SANS), Brief Assessment of Cognition in Schizophrenia (BACS), and other scales. RESULTS: D-cycloserine did not improve positive or negative symptoms or cognitive dysfunction in schizophrenia. The investigation in consideration of the onset age suggests that D-cycloserine may aggravate negative symptoms of early-onset schizophrenia. The better treatment effect of D-cycloserine on BACS was observed when the white matter integrity of the sagittal stratum/ cingulum/fornix stria terminalis/genu of corpus callosum/external capsule was higher, and the better treatment effect on PANSS general psychopathology (PANSS-G) was observed when the white matter integrity of the splenium of corpus callosum was higher. In contrast, the better treatment effect of D-cycloserine on PANSS-G and SANS-IV were observed when the white matter integrity of the posterior thalamic radiation (left) was lower. CONCLUSION: It was suggested that response to D-cycloserine is influenced by the onset age and white matter integrity. TRIAL REGISTRATION: UMIN Clinical Trials Registry (number UMIN000000468 ). Registered 18 August 2006.

HLA haploidentical hematopoietic cell transplantation using clofarabine and busulfan for refractory pediatric hematological malignancy.

Haploidentical hematopoietic cell transplantation (HCT) conditioning with clofarabine and target area under the blood concentration-time curve (AUC)-based busulfan adjustment was performed in three patients with refractory pediatric leukemia. The target AUC for two patients who had already received multiple transplantations was 3600 and 4000 µmol min/L, and that for the patient with Down's syndrome was 3000 µmol min/L. Regimen-related toxicity was well tolerated in all cases. All three maintained cytological remission throughout the follow-up period (between 31 and 167 weeks). Thus, haploidentical HCT conditioning with clofarabine and target AUC-based busulfan adjustment may be a preferable option for children with recurrent or refractory pediatric leukemia.

Effects of Miconazole Oral Gel on Blood Concentrations of Tacrolimus and Cyclosporine: A Retrospective Observational Study.

BACKGROUND: Although azole antifungal agents have been shown to affect the pharmacokinetics of calcineurin inhibitors such as tacrolimus (TAC) and cyclosporine (CyA) by inhibiting drug metabolism, there are few clinical reports on drug interactions between miconazole (MCZ) oral gel and calcineurin inhibitors. In this study, the effects of MCZ oral gel on the blood concentrations of TAC and CyA were investigated. METHODS: In this retrospective study, 18 patients concomitantly administered MCZ oral gel and TAC (9 for dermatomyositis, 3 for myasthenia gravis, 2 for systemic lupus erythematosus, 2 for rheumatoid arthritis, 1 for polymyositis, 1 for prevention of graft-versus-host disease after bone marrow transplantation), and 15 patients concomitantly administered MCZ oral gel and CyA (11 for interstitial pneumonia, 2 for pemphigus, 1 for eosinophilic granulomatosis with polyangiitis, 1 for systemic lupus erythematosus) were evaluated. The dose-adjusted blood concentrations of TAC or CyA were compared before and after the initiation of MCZ oral gel. RESULTS: The trough blood concentration/dose (C/D) ratios of TAC and CyA increased significantly with the administration of MCZ oral gel. The median C/D ratios of TAC and CyA increased by 108% (range: -44% to 216%) and 44% (range: -34% to 195%), respectively. CONCLUSIONS: These results suggest that MCZ oral gel affects the pharmacokinetics of TAC and CyA. Detailed monitoring of the blood concentrations of these drugs, followed by dose adjustments, is needed for each patient because of the difficulties associated with accurately predicting the degree of the effects of MCZ oral gel.

Mechanism Underlying Induction of Hyperglycemia in Rats by Single Administration of Olanzapine.

Acute administration of olanzapine rapidly elevates blood glucose levels. However, the mechanism underlying the rapid development of hyperglycemia with the administration of olanzapine remains unclear. The aim of the present study was to clarify the mechanism underlying olanzapine-induced acute hyperglycemia. Male Wistar rats received an intravenous infusion of saline (control) or olanzapine 2.5, 5, or 10 mg/kg. Blood samples were obtained periodically after olanzapine infusion to determine serum concentrations of glucose, olanzapine, and several endogenous substances. In a separate experiment, rats received an intravenous injection of propranolol (2 mg/kg) 30 min before infusion of olanzapine (10 mg/kg). The intravenous infusion of olanzapine induced dose-dependent increases in the serum concentrations of glucose, epinephrine, and insulin. Pretreatment with propranolol suppressed olanzapine-induced elevations in the serum concentration of glucose, but did not affect the serum concentration of olanzapine or olanzapine-induced increase in the serum concentration of epinephrine. Although the serum concentration of corticosterone increased after administration of olanzapine, no significant differences were observed among the olanzapine dose groups. Furthermore, administration of olanzapine did not affect the serum concentration of glucagon or histamine. We developed a pharmacokinetic-pharmacodynamic model assuming that the olanzapine-induced secretion of epinephrine leads to elevated serum glucose concentrations. This model appeared to satisfactorily characterize olanzapine-induced hyperglycemia. In conclusion, a single intravenous dose of olanzapine dose-dependently increased the serum concentration of glucose in rats, and epinephrine plays a role in olanzapine-induced acute hyperglycemia.

Haploidentical Bone Marrow Transplantation With Clofarabine and Busulfan Conditioning for a Child With Multiple Recurrent Acute Lymphoblastic Leukemia.

Outcome of children with acute lymphoblastic leukemia (ALL) has improved over the years, but not for those with multiple recurrences because of high therapy resistance and heavily pretreated history that potentially cause physical damages. We describe the case of an 11-year-old boy with a third relapse of ALL and a history of 2 allogeneic bone marrow transplantations. He was successfully treated with clofarabine combination chemotherapy and achieved a fourth remission at 16 months following haploidentical bone marrow transplantation with conditioning regimen of clofarabine and busulfan. Clofarabine/busulfan conditioning might be a preferable option for children with multiple recurrent ALL, and warrants further investigation.

Pharmacokinetic-pharmacodynamic analysis of sunitinib-induced thrombocytopenia in Japanese patients with renal cell carcinoma.

The aim of the present study was to clarify the therapeutic range and adequate dose of sunitinib in Japanese renal cell carcinoma patients by means of a pharmacokinetic-pharmacodynamic analysis of sunitinib-induced thrombocytopenia. Six patients with renal cell carcinoma were enrolled in this study. After starting the sunitinib treatment, between three and seven blood samples were obtained from each patient just before the administration of sunitinib. Serum concentrations of sunitinib and its active metabolite N-desethyl-sunitinib were fit to the 1-compartment model with first-order absorption. Changes in platelet counts were fit to the pharmacokinetic-pharmacodynamic model, in which the proliferation of platelet progenitor cells was assumed to be linearly inhibited by sunitinib and its metabolite. All patients using 50 mg as an initial dose of sunitinib developed grade 2 or 3 thrombocytopenia. The pharmacokinetic-pharmacodynamic model created successfully described the time course of sunitinib-induced thrombocytopenia and could predict changes in platelet counts after alterations to the dosage of sunitinib administered. The simulation results indicated that the total trough level of sunitinib to avoid severe thrombocytopenia should be <100 ng/mL, and also that the initial daily dose of sunitinib could be reduced to 37.5 mg or 25 mg in most Japanese patients. In addition to the pharmacokinetic-guided dosage adjustment, the careful monitoring of platelet counts is required for the safe use of sunitinib.

Active topical therapy by "Furuta method" for effective pressure ulcer treatment: a retrospective study.

BACKGROUND: We newly proposed that "Furuta method," a pharmacist intervention guidelines, is a topical ointment therapy that considers the physical properties and moist environment of wounds for pressure ulcer (PU) treatment. The aim of this multicenter retrospective study was to investigate the effectiveness of this method for PU. METHODS: A total of 888 consecutive patients who underwent treatment for PU at 37 hospitals and five dispensing pharmacies in Japan between August 2010 and July 2014 were included in the study. Based on a survey on compliance to "Furuta method," single-blind allocation was conducted into compliance (n = 437) and non-compliance (n = 451) groups, followed by a retrospective data collection. The primary and secondary outcomes were the healing period and rates of unhealed wounds, respectively. Data was expressed as mean ± standard deviation. Two-sided log rank tests were used for between-group comparisons of PU progression, whereas Kaplan-Meier plots were used for comparison between groups. We performed rigorous adjustment for marked differences in baseline patient characteristics by propensity score (PS) matching. RESULTS: After PS matching, patients were categorized as DESIGN-R d2 (n = 202), D3 (n = 130), D4 and 5 (n = 76), and DU (n = 76). In terms of the healing period, the patients in the compliance groups healed faster than those in the non-compliance groups in d2 (23.6 ± 36.8 vs. 32.2 ± 16.6 days; P < 0.001), D3 (46.8 ± 245.5 vs.137.3 ± 52.7 days; P < 0.001), and D4, 5 (122.5 ± 225.7 vs. 258.2 ± 292.7 days; P < 0.001). There were significantly lesser events of PU progression in the compliance group than in the non-compliance group (15 vs. 54; P = 0.003). CONCLUSIONS: "Furuta method" is the new therapeutic strategy of PU, a pharmacist intervention guidelines, may possibly increase healing rates of PUs.

Effects of moxifloxacin on serum glucose concentrations in rats.

Moxifloxacin, a fluoroquinolone antimicrobial agent, has been reported to cause serum glucose abnormalities such as hyper- and hypoglycemia. The purpose of the present study was to investigate the effect of moxifloxacin on serum glucose concentrations in rats. Rats were intravenously injected with moxifloxacin and samples of their arterial blood were collected periodically. Serum glucose concentrations increased with moxifloxacin at 100 mg/kg, and temporal elevations were observed in serum epinephrine and histamine concentrations. On the other hand, intravenous injection of moxifloxacin at 75 mg/kg did not affect serum glucose, epinephrine, or histamine concentrations. Serum immunoreactive insulin concentrations remained unchanged by moxifloxacin both at 75 and 100 mg/kg. In conclusion, moxifloxacin can induce histamine release, leading to an increase in serum epinephrine concentrations and hyperglycemia.

Effect of cimetidine on pentamidine induced hyperglycemia in rats.

The antiprotozoal agent pentamidine, used for the treatment of Pneumocystis jirovecii pneumonia (PCP), is known to cause abnormalities in blood glucose homeostasis, such as hypoglycemia and hyperglycemia. Pentamidine has been reported to be a substrate of organic cation transporter 1 (OCT1). We investigated the combination effects of cimetidine, an OCT1 inhibitor, on the pharmacokinetics of pentamidine and on pentamidine-induced hyperglycemia. Pentamidine was infused intravenously to rats for 20 min at a dose of 7.5 or 15 mg/kg and serum samples were obtained periodically. The serum concentration of glucose did not change significantly after pentamidine infusion at 7.5mg/kg, while it increased with pentamidine at 15 mg/kg, and the maximal concentration of glucose was 167 ± 36 mg/dl, 30 min after the start of pentamidine infusion. Cimetidine (50mg/kg) enhanced the pentamidine-induced elevation of glucose concentration and the maximal concentration of glucose was 208 ± 33 mg/dl in the pentamidine 15 mg/kg treated group. Cimetidine combination significantly reduced total body clearance of pentamidine and increased pentamidine concentrations in the liver, kidneys, and lungs. A significant correlation was found between changes in serum glucose concentrations and serum concentrations of pentamidine 30 min after the start of pentamidine infusion. These results suggest that the hyperglycemic effect of pentamidine is dependent on the concentration of pentamidine and can be enhanced by cimetidine combination.

Pharmacodynamics of cibenzoline-induced hypoglycemia in rats.

Hypoglycemia is one of the serious adverse effects induced by cibenzoline (CBZ), an antiarrhythmic agent. In order to clarify the pharmacodynamics of CBZ-induced hypoglycemia, CBZ was administered intravenously to conscious rats at a dose of 5, 10 or 20 mg/kg and serum samples were collected periodically to determine the concentrations of CBZ, insulin and glucose. The pharmacokinetics of CBZ showed nonlinear characteristics and could be described by a two-compartment model with Michaelis-Menten elimination kinetics. CBZ induced a rapid increase in the serum concentration of insulin. As the CBZ dose was increased, a greater hypoglycemic effect occurred. The indirect response model was applied to account for the CBZ-induced increase in insulin secretion and the subsequent decrease in serum glucose. A linear relationship was assumed between the serum concentration of CBZ and its stimulating effect on insulin secretion. A nonlinear relationship was assumed between the serum concentration of insulin and its stimulating effect on the elimination of serum glucose. The time courses of serum concentrations of CBZ, insulin and glucose after intravenous injection of CBZ could be described by the pharmacokinetic and pharmacodynamic model developed. This approach will be useful for the identification of variable factors related to CBZ-induced hypoglycemia.

Gatifloxacin-induced histamine release and hyperglycemia in rats.

Gatifloxacin, a fluoroquinolone antimicrobial agent, has been reported to cause both hypoglycemia and hyperglycemia in diabetic and non-diabetic patients. The purpose of the present study was to investigate the mechanism of gatifloxacin-induced hyperglycemia in normal and diabetic rats. Rats received a single intravenous injection of gatifloxacin and samples of their arterial blood were collected periodically. Diabetic rats were produced by the injection of streptozotocin and nicotinamide. In normal rats, the concentration of serum glucose decreased after the injection of gatifloxacin at 50mg/kg, while it increased with gatifloxacin at 100mg/kg. The concentrations of serum epinephrine and histamine increased after the injection of gatifloxacin at 100mg/kg. The increases in serum glucose and epinephrine concentrations were reduced by pretreatment with diphenhydramine at 1mg/kg. In diabetic rats, the concentration of serum glucose actually increased after the injection of gatifloxacin at 50mg/kg, concomitant with increases in the serum epinephrine and histamine concentrations. The concentration of serum immunoreactive insulin slightly increased after the injection of gatifloxacin at 50mg/kg. In addition, repeated oral administration of gatifloxacin to rats at 300 mg/kg twice a day for 7 days did not change glucose tolerance. In conclusion, gatifloxacin-induced release of histamine can contribute to an increase in the serum epinephrine concentration and hyperglycemia in normal rats. In diabetic rats, lower doses of gatifloxacin can induce hyperglycemia owing to the low level of insulin secretion that they exhibit compared with normal animals.