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PubMed2002

Efficacy and safety of tacrolimus ointment compared with that of hydrocortisone acetate ointment in children with atopic dermatitis.

BACKGROUND: Vehicle-controlled studies have demonstrated the efficacy and safety of tacrolimus ointment in the treatment of patients with atopic dermatitis (AD). OBJECTIVE: This study was undertaken to compare 0.03% and 0.1% tacrolimus ointment with 1% hydrocortisone acetate ointment in children 2 to 15 years of age with moderate-to-severe AD. METHODS: Treatment was twice daily to affected areas for 3 weeks in this multicenter, randomized, double-blind, parallel-group study. The primary endpoint was the modified eczema area and severity index (mEASI) mean area under the curve (mAUC) as a percentage of baseline. RESULTS: Five hundred sixty patients were randomized and received at least one application of ointment. Discontinuations included 21 of 189 patients from the 0.03% tacrolimus group, 13 of 186 patients from the 0.1% tacrolimus group, and 20 of 185 patients from the hydrocortisone acetate group. The median mEASI mAUC as a percentage of baseline showed 0.03% and 0.1% tacrolimus to be significantly more effective than 1% hydrocortisone acetate (P <.001) and 0.1% tacrolimus to be more effective than 0.03% tacrolimus (P =.006). The mEASI mAUC as a percentage of baseline was 44.8%, 39.8%, and 64.0% for patients who received 0.03% tacrolimus, 0.1% tacrolimus, and 1% hydrocortisone acetate, respectively. Transient skin burning was the only adverse event to show a higher incidence in the tacrolimus treatment groups than in the hydrocortisone acetate group (P <.05). Laboratory parameters showed no treatment differences and no marked changes over time. CONCLUSION: Tacrolimus, 0.03% and 0.1%, was significantly more effective than 1% hydrocortisone acetate and 0.1% tacrolimus was more effective than 0.03% tacrolimus in the treatment of moderate-to-severe AD in children. No safety concerns were identified.

Administration, Topical↗

PubMed2005

Higher initial tacrolimus blood levels and concentration-dose ratios in kidney transplant recipients who develop diabetes mellitus.

Posttransplantation diabetes mellitus (PTDM) is a common complication of kidney transplantation, associated with poorer graft and patient outcomes. Tacrolimus is a strong immunosuppressive drug associated with low acute rejection rates, but a higher risk for PTDM. High trough levels of tacrolimus during the first month after transplantation have been found to be a significant risk factor for the development of PTDM. The aim of this single-center study was to identify the risk factors for the development of PTDM among kidney transplant recipients under tacrolimus therapy. We examined 73 cadaveric kidney transplant recipients receiving tacrolimus between 1994 and 2003. Age, donor and recipient gender, dialysis method, body mass index (BMI), first year weight gain, mismatches, incidence of acute rejection and delayed graft function, hepatitis C serology, first year cumulative steroid dose, first tacrolimus blood level, first tacrolimus blood level <15 ng/mL, and corresponding tacrolimus daily doses and concentration/dose ratios (CDR) were also collected. PTDM was defined as at least 2 fasting blood glucose values > or =126 mg/dL, according to the World Health Organization criteria. Incidence of first year PTDM was 27.4%. Patients with PTDM showed significantly higher age, BMI, first tacrolimus blood level, first tacrolimus CDR, and CDR with tacrolimus blood level <15 ng/mL as well as less 1-year weight gain. After logistic regression, age (relative risk [RR] 1.060, confidence interval [CI] 95%, 1.001-1.122; P = .043) and first tacrolimus blood level (RR 1.154; CI 95%, 1.038-1.283; P = .008) remain significant risk factors for developing PTDM. Older age and initial tacrolimus blood levels were the main risk factors for PTDM among our group of patients. Kidney transplant recipients who develop PTDM maintain a high CDR of tacrolimus.

Adult↗

PubMed1999

Increased clearance of tacrolimus in children: need for higher doses and earlier initiation prior to bone marrow transplantation.

The pharmacokinetics of tacrolimus have been studied in healthy volunteers and in adults undergoing bone marrow transplantation. However, there is little information on the pharmacokinetics of tacrolimus in children undergoing BMT. We studied pharmacokinetics of tacrolimus in seven patients (age 8-17 years) undergoing allogeneic stem cell transplantation. Four patients received matched unrelated donor (MUD) transplants, two underwent HLA-matched related donor transplants, and one underwent an umbilical cord blood donor transplant. All patients received tacrolimus by continuous infusion at 0.03-0.04 mg/kg/day beginning on the day prior to transplant. Tacrolimus whole blood concentrations were monitored by microparticle enzyme immunoassay. Our goal was to maintain a blood tacrolimus level of 10-20 microg/ml. Once patients were tolerating oral medications, tacrolimus infusion was converted to oral dosing using a 4:1 conversion. Dose of tacrolimus and resulting tacrolimus concentrations were recorded and the total body clearance of tacrolimus was calculated retrospectively. The mean clearance, based on first steady-state tacrolimus concentrations necessary for achieving a therapeutic level (10-20 microg/ml), was 108.1 ml/h/kg (range 79.7-142.0 ml/h/kg), greater than that reported in adult BMT patients (71 +/- 34 ml/h/kg). The average dose required to achieve that therapeutic range was 0.0354 mg/kg/day as an intravenous continuous infusion. Over the entire course of intravenous tacrolimus, mean clearance was 97.0 ml/h/kg (range 33.4-153.3 ml/h/kg). In six of the seven patients, clearance values dropped after 2-4 weeks of therapy by an average of 32.5 ml/h/kg. In two patients, sharp drops in clearance were temporally related to changes in liver function tests. Three of the seven patients died of severe acute GVHD; all these had undergone matched unrelated donor transplantation, and two of these three had initial clearance levels over 120 ml/h/kg. Thus, children appear to have more rapid tacrolimus clearance than adults and may need to begin therapy earlier in order to obtain stable and optimal levels. More studies are needed to confirm these preliminary results.

Adolescent↗

PubMed2004

Factors affecting variability in distribution of tacrolimus in liver transplant recipients.

AIMS: Therapeutic drug monitoring (TDM) of tacrolimus is complicated by conflicting data on the correlation between tacrolimus trough blood concentrations and the incidence of rejection. The aim of this cross-sectional study was to investigate the blood distribution and protein binding of tacrolimus in liver transplant recipients to explore better predictors of clinical outcome. METHODS: Blood and plasma distribution of 3H-dihydro-tacrolimus was investigated in 40 liver transplant recipients using Ficoll Paque and density gradient ultracentrifugation, respectively, and equilibrium dialysis to investigate plasma protein binding. RESULTS: In blood tacrolimus was mainly associated with the erythrocyte fraction (83.2%, range 74.6-94.9%), followed by diluted plasma (16.1%, range 4.5-24.9%), and lymphocyte fraction (0.61%, range: 0.11-1.53%). In plasma, lipoprotein deficient serum fraction (54.2%, range 38.5-68.2%) was the main reservoir of tacrolimus. The unbound fraction of tacrolimus was found to be 0.47 +/- 0.18% (range 0.07-0.89%). The percentage of tacrolimus associated with the lymphocytes (0.8 +/- 0.4 vs 0.3 +/- 0.1%, P = 0.012) and estimated unbound concentration (0.42 +/- 0.21 ng l-1vs 0.24 +/- 0.08 ng l-1, P < 0.001) of tacrolimus were significantly different in stable transplant recipients and those experiencing rejection. Haematocrit and red blood cell count significantly influenced the percentage of tacrolimus associated with erythrocytes. The fraction unbound of tacrolimus was correlated with alpha1-acid glycoprotein and high density lipoprotein cholesterol concentrations. CONCLUSIONS: Tacrolimus unbound concentration was observed to be lower in liver transplant recipients experiencing rejection and further study is required to evaluate its utility in the TDM of tacrolimus.

Adult↗

PubMed2003

Tacrolimus dosage requirements after initiation of azole antifungal therapy in pediatric thoracic organ transplantation.

Azole antifungals inhibit the metabolism of tacrolimus mediated by CYP3A4. Upon initiation of azole therapy, the required dose reduction of tacrolimus is unknown. We reviewed our experience with azole antifungals in our pediatric thoracic transplant population receiving tacrolimus. Tacrolimus levels and dosage requirements were compared before and during azole therapy. Thirty-one patients received both tacrolimus and an azole antifungal (fluconazole = 9, itraconazole = 22). The tacrolimus dose was empirically reduced by approximately one-third when azole therapy was initiated. Mean tacrolimus dose requirements decreased by 68% within the first month of therapy (pre-azole: 0.27 +/- 0.14 mg/kg/day; 30 day post-azole: 0.087 +/- 0.069 mg/kg/day; p < 0.001). Despite a mean decrease in tacrolimus dose from baseline of 33, 42, and 55% on day 1, 2, and 4 of azole therapy, respectively, there was still an unintended 38% increase in tacrolimus levels during the first month of azole therapy. A calculated dose-reduction protocol of 50% on day of azole initiation, 70% on day 3, and 75% on day 14 should result in minimal mean changes in the tacrolimus levels. There was no difference in tacrolimus dose reduction between fluconazole and itraconazole groups. Azole antifungals markedly decrease tacrolimus requirements within the first few days of therapy. An initial reduction in tacrolimus dose by one-third is insufficient, and dose reduction of at least 50% upon azole initiation seems warranted. Once azole antifungal therapy is initiated, frequent therapeutic drug monitoring is required.

Analysis of Variance↗

PubMed2003

Effect of coadministered lopinavir and ritonavir (Kaletra) on tacrolimus blood concentration in liver transplantation patients.

With the advent of highly active antiretroviral therapy (HAART), HIV positivity is no longer a contraindication for liver transplantation. Some of the antiretroviral agents, particularly protease inhibitors (e.g., ritonavir, indinavir, and nelfinavir) have been described as potent inhibitors of the metabolism of certain immunosuppressive drugs. In this article we describe a profound interaction between tacrolimus and Kaletra (Abbott Laboratories, Chicago, IL) (a combination of lopinavir and ritonavir) in 3 liver transplantation patients. Patient 1, who was maintained on a 5 mg twice daily dose of tacrolimus with a trough blood concentration around 10.6 ng/mL, required only 0.5 mg of tacrolimus per week after addition of Kaletra to achieve similar tacrolimus blood concentrations, with a half-life of 10.6 days. In patient 2, the area under the blood concentration versus time curve for tacrolimus increased from 31 ng/mL/h to 301 ng/mL/h after addition of Kaletra, with a corresponding half-life of 20 days. When the patient was subsequently switched to nelfinavir, the half-life decreased to 10.3 days. Patient 3, who was maintained with 4 to 8 mg/d of tacrolimus and a corresponding blood concentration of 10 ng/mL before Kaletra, required a tacrolimus dose of 1 mg/wk and tacrolimus concentrations of 5 ng/mL with Kaletra. In conclusion, a combination of lopinavir and ritonavir led to a much more profound increase in tacrolimus blood concentrations than use of single protease inhibitor, nelfinavir. A tacrolimus dose of less than 1 mg/wk may be sufficient to maintain adequate blood tacrolimus concentrations in patients on Kaletra. Patients may not need a further dose of tacrolimus for 3 to 5 weeks depending on liver function when therapy with Kaletra is initiated. Great caution is required in the management of tacrolimus dosage when Kaletra is introduced or withdrawn in HIV-positive patients after liver transplantation, particularly in the presence of hepatic dysfunction.

Adult↗

PubMed2003

Pharmacokinetic interaction between corticosteroids and tacrolimus after renal transplantation.

BACKGROUND: Tacrolimus is an immunosuppressive drug that is a substrate of cytochrome P450 3A (CYP3A) enzymes and P-glycoprotein (P-gp). After transplantation, many pharmacological interactions have been described. Corticosteroids induce both CYP3A and P-gp activity. This study was designed to investigate the presence of a clinically significant interaction between steroids and tacrolimus after renal transplantation. METHODS: We studied 83 renal transplant recipients receiving tacrolimus after transplantation. Patients were divided into three groups, according to steroid dose (low: 0-0.15 mg/kg/day; intermediate: 0.16-0.25 mg/kg/day; and high: >0.25 mg/kg/day). All other medications, including those known to interact with CYP3A and/or P-gp, were recorded. Steroid dosage, tacrolimus dosage, tacrolimus trough concentration (C0) and tacrolimus concentration/dose ratio [C0 divided by the 24 h dosage (mg/kg)] were assessed for each dosage group after 1 and 3 months of tacrolimus treatment. RESULTS: The three groups were not different as regards the use of non-immunosuppressive treatments or clinical events. At 1 and 3 months, the tacrolimus doses and concentration/dose ratios differed significantly in the three steroid dosage groups. With the higher doses, higher tacrolimus doses were needed to achieve the blood tacrolimus targeted trough level. CONCLUSIONS: We demonstrated that pharmacokinetic interaction occurs between steroids and tacrolimus in renal transplant patients. The higher the steroid dosage, the higher the dosage of tacrolimus needed to achieve target trough levels in these patients. The most likely interaction mechanism is specific enzymatic induction of CYP3A and/or P-gp. Interaction is present, even when the steroid dosage is low. The clinical events liable to occur during steroid sparing or tapering must be taken into account because it may be associated with episodes of tacrolimus-related nephrotoxicity.

Adult↗

PubMed2003

Tacrolimus and mycophenolate mofetil provide effective immunosuppression in rat laryngeal transplantation.

OBJECTIVES/HYPOTHESIS: Tacrolimus is efficacious in several transplantation settings. Some studies have demonstrated improved results using combination therapy with mycophenolate mofetil. Our primary objective was to evaluate the efficacy and optimal dosing of tacrolimus in preventing rejection, using an established rat model of laryngeal transplantation. Further, the ability of mycophenolate to allow lower dosing of tacrolimus while achieving equivalent immunosuppression was investigated. STUDY DESIGN: A dosage efficacy study with 10 experimental arms was conducted. METHODS: Dosage groups were 0.1, 0.2, 0.3, and 0.6 mg/kg tacrolimus alone and 0.1 mg/kg tacrolimus combined with 15 mg/kg mycophenolate mofetil, 0.1 mg/kg tacrolimus combined with 30 mg/kg mycophenolate mofetil, 0.1 mg/kg tacrolimus combined with 40 mg/kg mycophenolate mofetil, 0.2 mg/kg tacrolimus combined with 15 mg/kg mycophenolate mofetil, 0.2 mg/kg tacrolimus combined with 30 mg/kg mycophenolate mofetil (30 d only), and 0.2 mg/kg tacrolimus combined with 40 mg/kg mycophenolate mofetil. Each group contained 8 to 10 rats. Grafts were harvested for histopathological analysis on day 15 or 30 after transplantation. Histopathological appearance of the graft was blindly graded according to an established scale. Dosage groups were compared on rejection score using Wilcoxon's rank sum test and the Jonckheere-Terpstra test for trend. RESULTS: There was a significant association between increasing dose of tacrolimus and decreasing rejection score at both 15 and 30 days (P <.001). In the groups treated with 0.1 mg/kg T, an increasing dose of mycophenolate was associated with lower rejection scores at both 15 and 30 days (P =.001). In the group treated with 0.2 mg/kg T, there was no evidence that the addition of mycophenolate resulted in lower rejection at 15 days. However, at 30 days, combination therapy with increasing doses of mycophenolate was associated with decreasing rejection score (P =.002). CONCLUSIONS: Tacrolimus is an effective immunosuppressive agent for laryngeal transplantation. Mycophenolate mofetil allows lower doses of tacrolimus to be used while preserving graft viability in the early post-transplantation period.

Animals↗

PubMed2003

Tacrolimus enhances transforming growth factor-beta1 expression and promotes tumor progression.

BACKGROUND: Immunosuppressive therapy is a risk factor for the increased incidence and metastatic progression of malignancies in organ graft recipients. Transforming growth factor (TGF)-beta(1) has been associated with tumor invasion and metastasis, and we have implicated cyclosporine-associated TGF-beta(1) hyperexpression in tumor progression in mice. METHODS: BALB/c mice or severe combined immunodeficient-beige mice were treated with 2 or 4 mg/kg of tacrolimus, and the effect of treatment on mouse renal cancer cell pulmonary metastasis was investigated. We also determined whether tacrolimus induces TGF-beta(1) expression. Spleens from tacrolimus-treated mice were analyzed for level of expression of TGF-beta(1) mRNA with the use of competitive-quantitative polymerase chain reaction assay, and circulating levels of TGF-beta(1) protein were measured with the use of an enzyme-linked immunosorbent assay. RESULTS: Treatment with tacrolimus resulted in a dose-dependent increase in the number of pulmonary metastases in the BALB/c mice (197+/-16 in untreated mice, 281+/-26 in mice treated with 2 mg/kg of tacrolimus, and 339+/-25 in mice treated with 4 mg/kg of tacrolimus; no treatment vs. 4 mg/kg tacrolimus, Bonferroni's P<0.001) and in the severe combined immunodeficient-beige mice (117+/-18 in untreated mice, 137+/-19 in mice treated with 2 mg/kg of tacrolimus, and 216+/-29 in mice treated with 4 mg/kg of tacrolimus; no treatment vs. 4 mg/kg tacrolimus, P<0.05). Treatment with 4 mg/kg but not 2 mg/kg of tacrolimus resulted in a significant increase in the levels of expression of TGF-beta(1) mRNA and circulating levels of TGF-beta(1) protein. CONCLUSIONS: Tacrolimus has a dose-dependent effect on tumor progression and TGF-beta(1) expression, and tacrolimus-induced TGF-beta(1) overexpression may be a pathogenetic mechanism in tumor progression.

Animals↗

PubMed2003

Increased topical tacrolimus absorption in generalized leukemic erythroderma.

OBJECTIVE: To report a case of elevated blood tacrolimus concentration after application of topical tacrolimus ointment in an erythrodermic patient. CASE SUMMARY: A 44-year-old man developed generalized erythroderma and itching due to infection with human T-cell lymphotropic virus. Despite application of strong glucocorticosteroid ointments, the symptoms and area of erythroderma were not alleviated. Daily topical application of tacrolimus 0.1% ointment was added and therapeutic drug monitoring was started. The dose and applied area of tacrolimus were gradually increased from 2.5 to 12.5 g/d and from 10% to 90% of body surface area, respectively. Because the trough concentration of tacrolimus in whole blood increased from 7.5 ng/mL on treatment day 9 to 15.4 ng/mL on day 13, the dose was reduced to 10 g/d. However, the concentration further elevated to 16.5 ng/mL. Therefore, the applied area was reduced to 20% of body surface area, and the tacrolimus concentration decreased gradually thereafter. Although the transient increase of blood tacrolimus concentration was observed on day 23, treatment with 20% applied area and 5 g/d were maintained. DISCUSSION: Topically applied tacrolimus was substantially absorbed with the expansion of its applied area and dose. Increased tacrolimus concentrations may have a tendency to depend on the increase of the percent of body surface area per dose. Our findings showing the elevation of blood tacrolimus concentration after application of the ointment to a large area of the body suggest that the applied area should be as narrow as possible in a barrier-disrupted condition such as erythroderma. However, the safety of tacrolimus ointment has not been established in patients with generalized erythroderma. CONCLUSIONS: Tacrolimus concentrations in whole blood should be carefully monitored to prevent nephrotoxicity. Based on the results of that monitoring, the application area and dose of tacrolimus ointment should be closely adjusted, especially in generalized erythrodermic cases.

Administration, Topical↗

PubMed2000

Tacrolimus: a further update of its pharmacology and therapeutic use in the management of organ transplantation.

UNLABELLED: Tacrolimus (FK-506) is an immunosuppressant agent that acts by a variety of different mechanisms which include inhibition of calcineurin. It is used as a therapeutic alternative to cyclosporin, and therefore represents a cornerstone of immunosuppressive therapy in organ transplant recipients. Tacrolimus is now well established for primary immunosuppression in liver and kidney transplantation, and experience with its use in other types of solid organ transplantation, including heart, lung, pancreas and intestinal, as well as its use for the prevention of graft-versus-host disease in allogeneic bone marrow transplantation (BMT), is rapidly accumulating. Large randomised nonblind multicentre studies conducted in the US and Europe in both liver and kidney transplantation showed similar patient and graft survival rates between treatment groups (although rates were numerically higher with tacrolimus- versus cyclosporin-based immunosuppression in adults with liver transplants), and a consistent statistically significant advantage for tacrolimus with respect to acute rejection rate. Chronic rejection rates were also significantly lower with tacrolimus in a large randomised liver transplantation trial, and a trend towards a lower rate of chronic rejection was noted with tacrolimus in a large multicentre renal transplantation study. In general, a similar trend in overall efficacy has been demonstrated in a number of additional clinical trials comparing tacrolimus- with cyclosporin-based immunosuppression in various types of transplantation. One notable exception is in BMT, where a large randomised trial showed significantly better 2-year patient survival with cyclosporin over tacrolimus, which was primarily attributed to patients with advanced haematological malignancies at the time of (matched sibling donor) BMT. These survival results in BMT require further elucidation. Tacrolimus has also demonstrated efficacy in various types of transplantation as rescue therapy in patients who experience persistent acute rejection (or significant adverse effect's) with cyclosporin-based therapy, whereas cyclosporin has not demonstrated a similar capacity to reverse refractory acute rejection. A corticosteroid-sparing effect has been demonstrated in several studies with tacrolimus, which may be a particularly useful consideration in children receiving transplants. The differences in the tolerability profiles of tacrolimus and cyclosporin may well be an influential factor in selecting the optimal treatment for patients undergoing organ transplantation. Although both drugs have a similar degree of nephrotoxicity, cyclosporin has a higher incidence of significant hypertension, hypercholesterolaemia, hirsutism and gingival hyperplasia, while tacrolimus has a higher incidence of diabetes mellitus, some types of neurotoxicity (e.g. tremor, paraesthesia), diarrhoea and alopecia. CONCLUSION: Tacrolimus is an important therapeutic option for the optimal individualisation of immunosuppressive therapy in transplant recipients.

Adult↗

PubMed1997

Tacrolimus (FK 506) overdose: a report of five cases.

INTRODUCTION: Tacrolimus (FK 506), a potent anti-T cell agent, has been shown to be effective in preventing the rejection of transplanted organs. Published research on tacrolimus has focused on effects associated with therapeutic use. Virtually no literature addresses the acute toxicity or the management of tacrolimus overdose. We report five cases of acute overdose with tacrolimus. CASE REPORTS: A 2-year-old female with no prior medical history ingested 10 mg of tacrolimus. She remained asymptomatic. A 2-year-old female with a history of multiple visceral organ transplants ingested 11 mg of her tacrolimus. She was admitted to the hospital and activated charcoal was administered. Her renal function was monitored and no changes were noted in a 24 h period. She was discharged. A 29-year-old male renal transplant patient took 150 mg of tacrolimus. He recovered with only a minimal creatinine elevation. A 23-year-old heart and lung transplant patient ingested 375 mg of tacrolimus. She had no effects from the overdose. A 34-year-old female experienced an acute/chronic overdose of 7-9 mg and remained asymptomatic. DISCUSSION: Tacrolimus is a neutral macrolide antibiotic that is extracted from the fermentation broth of the soil fungus Streptomyces tsukubaensis. Chronic oral dosing has been associated with numerous side effects. Although these patients ingested significant doses of tacrolimus, they suffered few toxic manifestations associated with tacrolimus. CONCLUSION: Little information is available regarding acute tacrolimus overdosage. In this small series of patients, tacrolimus did not produce acute physiologic incapacitation.

Adult↗

PubMedDate not supplied

Raloxifene does not affect the changes in bone histomorphometric parameters induced by low dose tacrolimus in male rats.

Raloxifene is a selective estrogen receptor modulator. The drug reduces bone loss and prevents fractures in postmenopausal women. Tacrolimus, an immunosuppressant, is used to prevent organ transplant rejection. The effect of raloxifene and tacrolimus on the osseous bone in men has not been exhaustively determined. To study the effects of raloxifene, tacrolimus as well as concurrent administration of raloxifene and tacrolimus on the osseous tissue in male rats, a preliminary assessment of the drug action on histomorphometric parameters of rat bones was made. The experiments were carried out on mature male Wistar rats. The animals were divided into six groups, 7 animals each: I--control rats; II--rats which were administered raloxifene (5 mg/kg po daily); III-- rats which were administered tacrolimus (0.3 mk/kg po daily); IV - rats which were administered tacrolimus (0.6 mg/kg po daily; V-- rats which were administered raloxifene (5 mg/kg po daily) and tacrolimus (0.3 mg/kg po daily); VI - rats which were administered raloxifene (5 mg/kg po daily) and tacrolimus (0.6 mg/kg po daily). The drugs were administered for 4 weeks. Body mass, macrometric parameters of the tibia, femur and L-4 vertebra, histomorphometric parameters of tibia (transverse growth, width of osteoid, area of the transverse cross section of bone marrow cavity and cortical bone), and the femur (width of trabeculae, width of epiphyseal cartilage) were examined. The action of raloxifene in male rats was demonstrated through increased width of osteoid. An increased traverse growth of bone and osteoid width as well as transverse cross section of the cortical bone and the marrow cavity and increased thickness of trabeculae were observed in male rats receiving tacrolimus at 0.3 mg/kg. The administration of tacrolimus at 0.6 mg/kg resulted in increased traverse growth of bone and increased thickness of osteoid, whereas the thickness of trabeculae remained unaffected. The results obtained in the rats administered concurrently raloxifene and tacrolimus (at 0.3 mg/kg or at 0.6 mg/kg) were similar to those obtained in the group of rats receiving tacrolimus at 0.3 mg/kg. It seems that the most valuable in entire experimental system of the study are the results obtained in the group receiving tacrolimus at 0.3 mg/kg po, which are indicative of intensified bone remodeling processes with dominant the bone formation process.

Animals↗

PubMed1995

Metabolism of the immunosuppressant tacrolimus in the small intestine: cytochrome P450, drug interactions, and interindividual variability.

The small intestinal metabolism of tacrolimus, which is used as an immunosuppressant in transplantation medicine, was investigated in this study. Tacrolimus was metabolized in vitro by isolated human, pig, and rat small intestinal microsomes. The metabolites generated were identified by HPLC/MS. Tacrolimus and its metabolites were quantified using HPLC or HPLC/MS. The cytochrome P450 (CYP) enzymes responsible for tacrolimus metabolism in small intestine were identified using specific CYP antibodies and inhibitors. For characterization of the interindividual variability, microsomes were isolated from small intestinal samples of patients who had undergone resection for various reasons. In an in vitro model using pig small intestinal microsomes, 32 drugs were analyzed for their interactions with tacrolimus metabolism. After incubation with human, rat, and pig small intestinal microsomes, the metabolites 13-O-demethyl and 13,15-O-demethyl tacrolimus were identified. The metabolism of tacrolimus by human small intestine was inhibited by anti-CYP3A, troleandomycin, and erythromycin, indicating that, as in the liver, CYP3A enzymes are the major enzymes for tacrolimus metabolism in the human small intestine. Metabolism of tacrolimus by small intestinal microsomes isolated from 14 different patients varied between 24 and 110 pmol/13-O-demethyl tacrolimus/min/mg microsomal protein, with a mean +/- SD of 54.2 +/- 29.2 pmol/min/mg. Of 32 drugs tested, 15 were found to inhibit small intestinal tacrolimus metabolism: bromocryptine, corticosterone, cyclosporine, dexamethasone, ergotamine, erythromycin, ethinyl estradiol, josamycin, ketoconazole, nifedipine, omeprazole, progesterone, rapamycin, troleandomycin, and verapamil. All of these drugs inhibited tacrolimus metabolism by human liver microsomes as well. It is concluded that tacrolimus is metabolized by cytochrome CYP3A enzymes in the small intestine. The rate of the CYP3A enzymatic activities varies about 5 times from patient to patient, and drugs that interfere with the in vitro metabolism of tacrolimus in the liver also inhibit its small intestinal metabolism.

Animals↗

PubMed1998

Single-center randomized trial comparing tacrolimus (FK506) and cyclosporine in the prevention of acute myocardial rejection.

BACKGROUND: To compare the efficacy and safety of tacrolimus and cyclosporine in heart transplantation, this single-center, prospective, randomized, open-label clinical trial was undertaken. METHODS: Seventy-three adult patients were randomly assigned at the time of transplantation to receive either tacrolimus (n=43) or cyclosporine (n=30) as the primary immunosuppressant. Ten of the 43 patients in the tacrolimus group received the drug intravenously in the perioperative period; all other patients received only oral tacrolimus. RESULTS: With a mean follow-up of 27 months, patient survival rates (tacrolimus 83%, cyclosporine 81%) were similar. Fewer patients experienced acute rejection in the tacrolimus group (79%) than in the cyclosporine group (100%), but the difference was not statistically significant. The number of infections and dialysis and insulin requirements were similar for the 2 treatment groups, but the proportion of patients requiring multidrug antihypertensive regimens was lower in the tacrolimus group (12.5% vs 50.0% at month 6; p=.025). The interpatient variance in pharmacokinetic parameters in a subset of 10 patients was much higher after the first oral dose of tacrolimus than at steady-state (eg, first-dose time at which maximal concentration is reached (t(max)): 3.5+/-2.5h, steady-state t(max): 2.0+/-0.7h), and patients treated with intravenous tacrolimus (n=13) rather than oral tacrolimus (n=30) reached target concentrations faster and with less interpatient variability (eg, at day 0: 9.72+/-10.9 ng/mL intravenously vs 3.31+/-8.1 orally). CONCLUSIONS: Tacrolimus was associated with similar efficacy and safety profiles compared with cyclosporine. The higher interpatient variance in absorption associated with oral tacrolimus during the first few days after transplantation would suggest that intravenous tacrolimus should be used during the perioperative period.

Administration, Oral↗

PubMed2002

Efficacy and safety of tacrolimus ointment compared with that of hydrocortisone butyrate ointment in adult patients with atopic dermatitis.

BACKGROUND: Vehicle-controlled studies have demonstrated the efficacy and safety of tacrolimus ointment for patients with atopic dermatitis. OBJECTIVE: This study was undertaken to compare 0.03% and 0.1% tacrolimus ointment with 0.1% hydrocortisone-17-butyrate ointment, a midpotent to potent topical corticosteroid, in the treatment of adult patients with moderate-to-severe atopic dermatitis. METHODS: Patients applied ointment twice daily to all affected areas for 3 weeks in this multicenter, randomized, double-blind, parallel-group study. The primary endpoint was the modified eczema area and severity index (mEASI) mean area under the curve as a percentage of baseline. RESULTS: Five hundred seventy patients were randomized and received treatment. Discontinuations included 22 of 193 patients from the 0.03% tacrolimus group, 22 of 191 patients from the 0.1% tacrolimus group, and 17 of 186 patients from the hydrocortisone butyrate group. The median mEASI mean area under the curve as a percentage of baseline was 47.0%, 36.5%, and 36.1% for patients who received 0.03% tacrolimus, 0.1% tacrolimus, and 0.1% hydrocortisone butyrate, respectively. There was no statistically significant difference between 0.1% tacrolimus and 0.1% hydrocortisone butyrate; however, the lower improvement in mEASI for 0.03% tacrolimus was statistically significant when compared with 0.1% tacrolimus (P <.001) or hydrocortisone butyrate (P =.002). Skin burning and pruritus at the application site showed a higher incidence in the tacrolimus treatment groups than in the hydrocortisone butyrate group (P <.05). Laboratory parameters showed no treatment differences and no marked changes over time. CONCLUSIONS: The efficacy of 0.1% tacrolimus ointment was similar to that of 0.1% hydrocortisone butyrate ointment and was lower for 0.03% tacrolimus ointment. No serious safety concerns were identified.

Administration, Topical↗

PubMed2006

Cyclosporin versus tacrolimus for liver transplanted patients.

BACKGROUND: Most liver transplant recipients receive either cyclosporin or tacrolimus to prevent rejection. Both drugs inhibit calcineurin phosphatase which is thought to be the mechanism of their anti-rejection effect and principle toxicities. The drugs have different pharmacokinetic profiles and potencies. Several randomised clinical trials have compared cyclosporin and tacrolimus in liver transplant recipients, but it remains unclear which is superior. OBJECTIVES: To evaluate the beneficial and harmful effects of immunosuppression with cyclosporin versus tacrolimus for liver transplanted patients. SEARCH STRATEGY: The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials in The Cochrane Library, MEDLINE, EMBASE, and Science Citation Index Expanded, and conference proceedings were searched (August 2005) to identify relevant randomised clinical trials. Our search included scanning of reference lists in relevant articles and correspondence with investigators and pharmaceutical companies. SELECTION CRITERIA: All randomised clinical trials where tacrolimus was compared with cyclosporin for the initial treatment of first-time liver transplant recipients. We included randomised trials irrespective of blinding, language, and publication status. DATA COLLECTION AND ANALYSIS: The primary outcome measure was all-cause mortality. Data were synthesised (fixed-effect model) and results expressed as relative risk (RR), values less than 1.0 favouring tacrolimus, with 95% confidence intervals (CI). Two authors assessed trials for eligibility, quality, and extracted data independently. MAIN RESULTS: We included 16 randomised trials. The number of deaths was 254 in the tacrolimus group (1899 patients) and 302 in the cyclosporin group (1914 patients). At one year, mortality (RR 0.85, 95% CI 0.73 to 0.99) and graft loss (RR 0.73, 95% CI 0.61 to 0.86) were significantly reduced in tacrolimus-treated recipients. Tacrolimus reduced the number of recipients with acute rejection (RR 0.81, 95% CI 0.75 to 0.88), and steroid-resistant rejection (RR 0.54, 95% CI 0.47 to 0.74) in the first year. Differences were not seen with respect to lymphoproliferative disorder or de-novo dialysis rates, but more de-novo insulin-requiring diabetes mellitus (RR 1.38, 95% CI 1.01 to 1.86) occurred in the tacrolimus group. More patients were withdrawn from cyclosporin therapy than from tacrolimus (RR 0.57, 95% CI 0.49 to 0.66). AUTHORS' CONCLUSIONS: Tacrolimus is superior to cyclosporin in improving survival (patient and graft) and preventing acute rejection after liver transplantation, but it increases the risk of post-transplant diabetes. Treating 100 recipients with tacrolimus instead of cyclosporin would avoid acute rejection and steroid-resistant rejection in nine and seven patients, respectively, and graft loss and death in five and two patients, respectively, but four additional patients would develop diabetes after liver transplantation.

Cyclosporine↗

PubMed2002

Roles of the jejunum and ileum in the first-pass effect as absorptive barriers for orally administered tacrolimus.

BACKGROUND: The immunosuppressant tacrolimus shows poor and variable bioavailability following oral administration in clinical use. Recently, the hepatic and intestinal metabolisms, or first-pass effect, of tacrolimus have been suggested to be responsible for its bioavailability. In the present study, we investigated the respective contribution of the jejunum and ileum to the first-pass effect of tacrolimus in rats. METHODS: The metabolism of tacrolimus in everted sacs of the duodenum, jejunum, and ileum was examined. Tacrolimus was administered intravenously or intraintestinally to sham-operated, jejunum-resected, or ileum-resected rats. Blood samples were collected over a 240-min period, and whole-blood tacrolimus concentrations were measured by semiautomated microparticle enzyme immunoassay. The pharmacokinetic parameters of tacrolimus in each group were estimated. RESULTS: The metabolic activity of tacrolimus appeared to be the highest in the everted sacs of the duodenum. The bioavailability of tacrolimus in the jejunum- or ileum-resected rats was higher than that in sham-operated controls. On the other hand, the time to peak concentration in the jejunum-resected rats was about twofold slower than those in ileum-resected and sham-operated rats. CONCLUSIONS: These results suggested that the first-pass effect of tacrolimus in the small intestine shows regional differences and the extraction of tacrolimus in the small intestine consists of the amount of extraction in the jejunum and ileum. In addition, the ileum rather than the jejunum as a graft of segmental small bowel transplantation would be useful to avoid the adverse effects of tacrolimus.

Administration, Oral↗