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1.
Bone Marrow Transplant ; 44(2): 75-9, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19169288

ABSTRACT

High-dose chemotherapy (HDT) and hematopoietic SCT are effective in patients with relapsing or refractory malignant lymphoma. Collection of sufficient numbers of stem cells is a prerequisite for such a therapy. In a pilot trial, we evaluated the feasibility of stem cell mobilization with vinorelbine/G-CSF in patients with lymphoma, a regimen allowing precise timing and harvesting of sufficient stem cells in myeloma patients. Forty-five patients with lymphoma received vinorelbine 35 mg/m(2) i.v. on day 1 and G-CSF 10 microg/kg/day s.c., divided in two daily doses from day 4 until collection. Stem cell collection was successfully performed in 43 patients (96%) with a median of 3.6 x 10(6) CD34(+) cells/kg (range: 1.4-16) in the collected product. In 28 patients (62%), the first stem cell apheresis was performed on day 8, and for 28 patients a sufficient stem cell yield was reached with one apheresis only. All 43 patients underwent high-dose chemotherapy with BEAM and auto-SCT with hematological recovery on time and without unexpected toxicity. In conclusion, vinorelbine/G-CSF allows accurate timing and safe harvesting of sufficient stem cells in patients with malignant lymphoma.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Granulocyte Colony-Stimulating Factor/therapeutic use , Hematopoietic Stem Cell Mobilization/methods , Hematopoietic Stem Cell Transplantation , Hodgkin Disease/therapy , Lymphoma, Non-Hodgkin/therapy , Vinblastine/analogs & derivatives , Adult , Aged , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Drug Costs , Granulocyte Colony-Stimulating Factor/administration & dosage , Humans , Middle Aged , Pilot Projects , Transplantation, Autologous , Vinblastine/administration & dosage , Vinblastine/therapeutic use , Vinorelbine
2.
Ther Umsch ; 63(1): 78-82, 2006 Jan.
Article in German | MEDLINE | ID: mdl-16450737

ABSTRACT

The first step in evaluating leukopenia is the analysis of the different leukocyte subpopulations. The automated total blood cell count gives a first impression of the decreased leukocyte subtype and if erythrocytes and/or platelets are involved. Microscopic interpretation of the blood smear verifies the automated differential and allows a statement on the morphology of the individual cells. Differential diagnosis of the decreased leukocyte subpopulation is vast and in many cases leukopenia is only an epiphenomenona of a systemic disease. Therefore therapy is always directed towards the underlying disorder.


Subject(s)
Hematologic Tests/methods , Leukopenia/blood , Leukopenia/diagnosis , Diagnosis, Differential , Humans , Leukopenia/pathology , Neutropenia/blood , Neutropenia/diagnosis , Neutropenia/pathology , Practice Guidelines as Topic , Practice Patterns, Physicians'
3.
Ther Umsch ; 61(2): 172-7, 2004 Feb.
Article in German | MEDLINE | ID: mdl-15018402

ABSTRACT

Thrombocytopenia has many causes. History, clinical examination of the patient, and a careful analysis of the peripheral blood smear may already lead to the etiology of cytopenia. The aim of the treatment is the correction of the underlying disease. In the management of immune thrombocytopenic purpura, the most common form of thrombocytopenia in adults, the goal is to avoid hemorrhages and not to increase the platelet value to normal.


Subject(s)
Thrombocytopenia/etiology , Adult , Diagnosis, Differential , Hemorrhagic Disorders/diagnosis , Hemorrhagic Disorders/etiology , Hemorrhagic Disorders/therapy , Humans , Platelet Count , Prognosis , Purpura, Thrombocytopenic, Idiopathic/diagnosis , Purpura, Thrombocytopenic, Idiopathic/etiology , Purpura, Thrombocytopenic, Idiopathic/therapy , Risk Factors , Thrombocytopenia/diagnosis , Thrombocytopenia/therapy
4.
Praxis (Bern 1994) ; 92(16): 763-8, 2003 Apr 16.
Article in German | MEDLINE | ID: mdl-12741100

ABSTRACT

Choriocarcinoma are malignant neoplastic tumors from the trophoblastic tissue with a tendency to early metastases. Beside pulmonary metastases there are often cerebral metastases, leading to intracerebral hemorrhage often responsible for the first clinical symptoms. In young women, symptoms like vaginal or pulmonary bleeding or neurologic disturbances shortly after a hydatiform mole or a normal pregnancy, accompanied by high levels of HCG in serum and CSF, choriocarcinoma should be considered. Choriocarcinoma are very sensitive to chemotherapy, which consists--depending on the stage of the disease--of a mono- or polychemotherapy. Cure rates are high, even in extended stages with cerebral metastases--as in the case described. Brain metastases with or without oncotic aneurysms can be rapidly controlled by immediate whole brain irradiation. Surgical interventions may be necessary in the case of life threatening bleedings. Levels of HCG in serum and cerebrospinal fluid are good markers to control the effect of therapy. But--as shown in this patient--levels of HCG in CSF may decrease protracted without affecting prognosis. Oncotic aneurysms are rarely reported and mostly detected post mortem. The presented case leads to a more optimistic attitude and demonstrates efficacy of immediately started radio- and chemotherapy.


Subject(s)
Brain Neoplasms/secondary , Choriocarcinoma/secondary , Uterine Neoplasms , Adult , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Blindness/etiology , Brain Neoplasms/complications , Brain Neoplasms/diagnostic imaging , Brain Neoplasms/drug therapy , Brain Neoplasms/radiotherapy , Cerebral Angiography , Choriocarcinoma/complications , Choriocarcinoma/diagnostic imaging , Choriocarcinoma/drug therapy , Choriocarcinoma/radiotherapy , Chorionic Gonadotropin/blood , Chorionic Gonadotropin/cerebrospinal fluid , Combined Modality Therapy , Dactinomycin/therapeutic use , Doxorubicin/therapeutic use , Etoposide/therapeutic use , Female , Follow-Up Studies , Humans , Intracranial Aneurysm/complications , Intracranial Aneurysm/diagnostic imaging , Leucovorin/therapeutic use , Methotrexate/therapeutic use , Pregnancy , Prognosis , Radiotherapy Dosage , Time Factors , Tomography, X-Ray Computed , Vincristine/therapeutic use
5.
Bone Marrow Transplant ; 31(2): 99-103, 2003 Jan.
Article in English | MEDLINE | ID: mdl-12621490

ABSTRACT

Cyclophosphamide with granulocyte colony stimulating factor (G-CSF) is commonly used to mobilize stem cells in multiple myeloma. Timing of collection is variable and incidence and severity of side effects is substantial. To optimize timing of collection, to reduce side effects and to limit costs of the procedure, we evaluated vinorelbine, a drug shown to have activity in multiple myeloma, in combination with G-CSF as mobilizing regimen. A total of 19 consecutive patients with advanced stage multiple myeloma received one dose of vinorelbine 35 mg/m(2) intravenously on day 1 in an outpatient setting and G-CSF 10 microg/kg/day from day 4 divided in two daily doses. Median CD34+ cell blood counts measured on day 8 of mobilization were 142 x 10(6)/l (range 57-467). One 15-l apheresis on day 8 resulted in sufficient stem cells (median 11.1 x 10(6) CD34+ cells/kg, range 6.2-36.0 prior and median 7.5 x 10(6) CD34+ cells/kg, range 4.0-20.2 post-positive CD34+ cell selection) for transplantation. Hematopoietic recovery was swift with ANC >0.5 x 10(9)/l on day 11 median (range 10-15) and platelets >20 x 10(9)/l on day 12 median (range 10-15) after reinfusion of the stem cells on day 0. No episodes of febrile neutropenia were observed during mobilization. In our institutions cost reduction for the procedure was about 1700 euros compared to the mobilization with cyclophosphamide and G-CSF. Vinorelbine and G-CSF allow precise timing and harvesting of sufficient stem cells, and might be an alternative to cyclophosphamide in the mobilization of stem cells for autologous transplantation in multiple myeloma.


Subject(s)
Granulocyte Colony-Stimulating Factor/therapeutic use , Hematopoietic Stem Cell Mobilization/methods , Multiple Myeloma/therapy , Stem Cell Transplantation/methods , Vinblastine/analogs & derivatives , Vinblastine/therapeutic use , Aged , Antigens, CD/blood , Antigens, CD34/blood , Cost-Benefit Analysis , Female , Granulocyte Colony-Stimulating Factor/adverse effects , Granulocyte Colony-Stimulating Factor/economics , Humans , Male , Middle Aged , Multiple Myeloma/drug therapy , Recombinant Proteins , Switzerland , Vinblastine/adverse effects , Vinblastine/economics , Vinorelbine
6.
Am J Hematol ; 66(2): 142-4, 2001 Feb.
Article in English | MEDLINE | ID: mdl-11421295

ABSTRACT

Paraneoplastic pemphigus is a severe mucocutaneous disease associated in most cases with B-cell lymphoproliferative disorders. Independent of the course of the underlying malignancy, this autoimmune skin disease is resistant to any treatment in most cases and may lead to death by infectious complications. We observed a patient with recovery of paraneoplastic pemphigus associated with follicular non-Hodgkin's-lymphoma after therapy with rituximab. In addition, we reviewed the literature and analyzed the few cases with comparable outcome with other treatment modalities.


Subject(s)
Antibodies, Monoclonal/administration & dosage , Lymphoma, Follicular/complications , Pemphigus/drug therapy , Aged , Antibodies, Monoclonal, Murine-Derived , Antineoplastic Agents/administration & dosage , Female , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/complications , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Lymphoma/complications , Lymphoma/drug therapy , Lymphoma, Follicular/drug therapy , Paraneoplastic Syndromes/drug therapy , Pemphigus/etiology , Rituximab
8.
Cancer Genet Cytogenet ; 113(1): 90-2, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10459354

ABSTRACT

A 66-year-old Caucasian woman presented with a Philadelphia chromosome positive common B-cell acute lymphoblastic leukemia and a dic(9;12) involving the der(9)t(9;22), a rearrangement so far not observed in acute lymphoblastic leukemia. The patient was treated for the acute lymphoblastic leukemia, but showed refractory disease and died 6 months after initial diagnosis. This case suggests that, in the combination of t(9;22) and dic(9;12), the known poor prognostic feature of t(9;22) in acute lymphoblastic leukemia may outweigh the favorable outcome reported in patients with dic(9;12).


Subject(s)
Burkitt Lymphoma/genetics , Chromosomes, Human, Pair 12 , Chromosomes, Human, Pair 9 , Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics , Translocation, Genetic , Aged , Chromosome Banding , Female , Humans , Karyotyping , Recurrence
9.
Bone Marrow Transplant ; 20(7): 607-9, 1997 Oct.
Article in English | MEDLINE | ID: mdl-9337064

ABSTRACT

We observed the occurrence of celiac disease following allogeneic bone marrow transplantation in a patient transplanted for acute leukemia. The marrow donor was his HLA-identical sister, who had suffered from celiac disease since birth. The post-transplant period was characterized by recurrent episodes of diarrhea. Detailed workup showed atrophic intestinal mucosa on histology and anti-gliadin and anti-endomysium antibodies in the serum, features that were not present before transplantation. GVHD was absent at that time. The patient remains free of symptoms on gluten-free diet and slight immunosuppression. This case suggests transmission of celiac disease by bone marrow transplantation and supports the T cell concept in celiac disease.


Subject(s)
Bone Marrow Transplantation/adverse effects , Celiac Disease/etiology , Leukemia/therapy , Acute Disease , Adolescent , Celiac Disease/immunology , Humans , Lymphocyte Depletion , Male , T-Lymphocytes/immunology , Transplantation, Homologous
11.
Schweiz Med Wochenschr ; 126(45): 1944-5, 1996 Nov 09.
Article in German | MEDLINE | ID: mdl-8946598

ABSTRACT

In acute promyelocytic leukemia (APL), disseminated intravascular coagulation is frequently observed. Massive alveolar bleeding can lead to respiratory insufficiency, requiring tracheal intubation and mechanical ventilation. Today all-transretinoic acid (ATRA) is part of induction chemotherapy in acute promyelocytic leukemia. The administration of ATRA is oral. No intravenously administered form is available. ATRA can be administered to intubated patients in the following manner: the daily amount of ATRA is placed in a sterile 50 ml tube. After addition of about 20 ml of sterile water the tube is heated in a waterbath to a temperature of 37 degrees C until the capsules melt and the suspension is completely liquid. The resulting oily fluid is then administered via nasogastric tube. We have treated 2 patients with acute promyelocytic leukemia intubated due to massive alveolar bleeding in this manner, and have observed a differentiation of promyelocytes to granulocytes and complete remission in both patients, indicating that the ATRA administered had been resorbed intestinally.


Subject(s)
Antineoplastic Agents/therapeutic use , Leukemia, Promyelocytic, Acute/drug therapy , Tretinoin/therapeutic use , Adolescent , Adult , Female , Humans , Male , Remission Induction , Treatment Outcome
12.
Ann Hematol ; 73(3): 149-51, 1996 Sep.
Article in English | MEDLINE | ID: mdl-8841105

ABSTRACT

Optimum treatment of severe neutropenia, a major factor for morbidity and mortality in T-large granular lymphocyte (LGL) leukemia, is undefined. We observed a rapid improvement of the neutrophil count in a patient with T-LGL leukemia and severe neutropenia after the combined administration of antilymphocyte-globulin (ALG), cyclosporin A, prednisone, and granulocyte colony-stimulating factor (G-CSF). Although G-CSF treatment was terminated after 7 days, the neutrophil count has persisted above 1.0 x 10(9)/1 for up to 6 months now. Oral methotrexate is given continuously as treatment for T-LGL leukemia. The response to this immunosuppressive regimen suggests a T-cell-mediated mechanism as the underlying cause for neutropenia in T-LGL leukemia.


Subject(s)
Immunosuppression Therapy , Leukemia, Lymphoid/therapy , Leukemia, T-Cell/therapy , Neutropenia/therapy , Humans , Leukocyte Count , Male , Middle Aged , Neutropenia/pathology , Neutrophils/pathology
13.
Br J Haematol ; 91(2): 306-12, 1995 Oct.
Article in English | MEDLINE | ID: mdl-8547066

ABSTRACT

In a prospective open-labelled phase I/II trial we tested efficacy and tolerability of recombinant human interleukin-3 (rhIL-3) alone in patients with refractory severe aplastic anaemia (SAA). 15 patients with idiopathic (12 patients) or secondary (one post-hepatitic, one drug induced, one dyskeratosis congenita) SAA, refractory or relapsing after one to three courses of antilymphocyte globulin were included. 14 patients were transfusion dependent (RBC 14, platelet 12). RhIL-3 was planned for three patients each at five escalating dose levels of 1, 2, 4, 8 and 16 micrograms/kg, given daily as 24 h continuous infusion for 21 d. RhIL-3 was prematurely withdrawn at days 10 and 11 for adverse events in two patients. 9/15 patients showed an increase in WBC; 2/6 at the 1-2 micrograms/kg and 7/9 at the 4-16 micrograms/kg level, but no sustained effects were seen. No patient showed a response in platelet counts. Additionally, platelet and RBC transfusion requirements were unchanged pre and post study. All patients experienced one or more adverse event, mainly fever (15 patients), bleeding (nine patients), and headache (six patients). Occurrence of adverse events was dose related and the maximum tolerated dose was reached with 8 micrograms/kg. Five patients suffered serious adverse events. RhIL-3 as single growth factor and used alone is of minimal benefit in severe aplastic anaemia.


Subject(s)
Anemia, Aplastic/therapy , Interleukin-3/therapeutic use , Adolescent , Adult , Antibodies/analysis , Female , Hemorrhage/etiology , Humans , Infections/etiology , Interleukin-3/adverse effects , Interleukin-3/immunology , Leukocyte Count , Male , Platelet Count , Prospective Studies , Recombinant Proteins/therapeutic use
14.
Schweiz Med Wochenschr ; 125(9): 433-5, 1995 Mar 04.
Article in German | MEDLINE | ID: mdl-7534433

ABSTRACT

Hydroxyurea is used in the treatment of sickle cell anemia and beta-thalassemia major to increase the content of hemoglobin F (HbF) and presumably ameliorate clinical symptoms. Under therapy with hydroxyurea an increase of the mean corpuscular volume (MCV) of the erythrocytes can be observed. To evaluate a possible estimation of the content of HbF using the increase of MCV under treatment with hydroxyurea, we measured MCV and HbF during therapy with hydroxyurea. The median MCV before therapy was 87.8 fl (range 74.3-95.7) and under hydroxyurea 104.1 fl (81.0-139.5), and the median HbF 1.8% (0.1-5.4). Although both MCV and HbF increased under treatment with hydroxyurea, a linear correlation between these two parameters was not detectable. Therefore, MCV cannot replace the measurement of HbF.


Subject(s)
Erythrocyte Indices , Fetal Hemoglobin/analysis , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/blood , Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy , Thrombocytosis/blood , Thrombocytosis/drug therapy , Female , Humans , Male , Middle Aged
15.
Cancer Res ; 53(17): 4010-3, 1993 Sep 01.
Article in English | MEDLINE | ID: mdl-8395334

ABSTRACT

Sustained release or high levels of interleukin-1 (IL-1) and/or tumor necrosis factor (TNF), as observed after endotoxin challenge, can produce a variety of toxicities. Naturally occurring inhibitors to IL-1 and TNF, IL-1 receptor antagonist (IL-1ra) and soluble TNF receptor forms, have been detected. These proteins may function to buffer or limit the effects of these cytokines as part of a regulatory network. As part of a clinical trial of recombinant human interleukin-1 beta (rhIL-1 beta), serial plasma samples were obtained from 6 patients with metastatic melanoma treated with 30-min infusions of rhIL-1 beta for 5 consecutive days. The presence of circulating IL-1 receptor antagonist and soluble TNF binding proteins (TNF-R55-BP and TNF-R75-BP) were assessed. A maximum 86-fold increase for IL-1ra, a 7-8-fold increase for TNF-R55-BP, and a 2-3-fold increase for TNF-R75-BP were seen 2-4 h, 1 h, and 4 h, respectively, after rhIL-1 beta infusion. On each day of the treatment, the secretion of IL-1ra and release of TNF-R55-BP was observed, but there was no accumulation above baseline value for IL-1ra before each of the 5 daily infusions. Although there was a steady decrease of the 6-h postinfusion plasma levels for IL-1ra and TNF-R55-BP over the 5 treatment days, no increase of clinical side effects was noted. Two patients had measurable levels of TNF-alpha, but no correlation to TNF-binding proteins was observed. Our data show that early after rhIL-1 beta infusion the induction of IL-1ra secretion, as well as TNF-binding protein release, is observed.


Subject(s)
Interleukin-1/pharmacology , Melanoma/blood , Receptors, Cell Surface/analysis , Sialoglycoproteins/blood , Adult , Aged , Female , Humans , Interleukin 1 Receptor Antagonist Protein , Interleukin-1/administration & dosage , Interleukin-1/adverse effects , Male , Melanoma/therapy , Middle Aged , Receptors, Tumor Necrosis Factor , Time Factors
16.
Naunyn Schmiedebergs Arch Pharmacol ; 347(6): 664-6, 1993 Jun.
Article in English | MEDLINE | ID: mdl-8361551

ABSTRACT

The effect of N-acetyl-L-cysteine on the cytotoxicity of tumor necrosis factor-alpha was investigated in cultured bovine pulmonary artery endothelial cells and L929 mouse tumor cells. In endothelial cells, a 72-h incubation with tumor necrosis factor-alpha (100 ng/ml) reduced the number of viable cells to 27% of control. Simultaneous incubation with N-acetyl-L-cysteine (0.5-5 mmol/l) protected endothelial cells from tumor necrosis factor-alpha-mediated cytotoxicity and increased viability in a concentration-dependent fashion to 69% of control. Under the same conditions, a 72-h incubation with tumor necrosis factor-alpha (100 ng/ml) reduced the number of viable L929 tumor cells to 31% of control. However, this cytotoxic response remained unaltered in the presence of N-acetyl-L-cysteine (0.5-5 mmol/l). Similar results were obtained when using a lower concentration of tumor necrosis factor-alpha (50 ng/ml). These findings demonstrate protection from tumor necrosis factor-alpha-mediated toxicity by N-acetyl-L-cysteine in endothelial cells but not in a tumor cell line. It is concluded that N-acetyl-L-cysteine might serve as a therapeutic agent to limit the vascular toxicity of tumor necrosis factor-alpha without affecting its antineoplastic activity.


Subject(s)
Acetylcysteine/pharmacology , Endothelium, Vascular/drug effects , Tumor Necrosis Factor-alpha/toxicity , Animals , Cattle , Cell Survival/drug effects , Endothelium, Vascular/cytology , Mice , Pulmonary Artery/cytology , Pulmonary Artery/drug effects , Tumor Cells, Cultured , Tumor Necrosis Factor-alpha/antagonists & inhibitors
17.
J Immunother Emphasis Tumor Immunol ; 13(2): 136-40, 1993 Feb.
Article in English | MEDLINE | ID: mdl-8318499

ABSTRACT

Administration of interleukin-1 beta (IL-1 beta) to humans initiates a cascade of metabolic, hematologic, and cardiovascular events. To investigate the role of the sympathetic nervous system in the early cardiovascular response to IL-1 beta in humans, we recorded the heart rate, blood pressure, and changes in hand vein compliance in five patients with malignant melanoma treated with a 30-min infusion of 10,000-20,000 U/kg of human recombinant IL-1 beta. All patients developed fever, chills, and marked hemodynamic changes. During or shortly after the infusion, a dramatic decrease in hand vein compliance occurred (vasoconstriction). At the time of maximum venoconstriction (35 min after the start of the IL-1 beta infusion), the mean heart rate and systolic blood pressure were significantly increased by 30 mm Hg and 31 beats/min, respectively. Venoconstriction always preceded the onset of chills by several minutes (mean of 7 min), was closely correlated with the heart rate, and could be reversed by local administration of the alpha-antagonist phentolamine, indicating involvement of catecholamines. Our study shows that cardiovascular responses that occur early after IL-1 beta administration in humans are most likely the result of adrenergic stimulation possibly through its effect on the central nervous system.


Subject(s)
Interleukin-1/pharmacology , Sympathetic Nervous System/physiology , Adult , Aged , Blood Pressure/drug effects , Female , Heart Rate/drug effects , Humans , Immunotherapy , Infusions, Intravenous , Interleukin-1/therapeutic use , Male , Melanoma/physiopathology , Melanoma/therapy , Middle Aged , Recombinant Proteins/therapeutic use , Vasoconstriction/drug effects
18.
Schweiz Med Wochenschr ; 121(12): 424-8, 1991 Mar 23.
Article in German | MEDLINE | ID: mdl-2028246

ABSTRACT

Intrapulmonary sequestration is a rare disorder which should be considered when an intrathoracic mass is found in the lower part of the lungs. The clinical symptoms range, as in our two patients, from an asymptomatic mass in the chest X-ray film to frequent pulmonary infections. A definite diagnosis is possible only by visualization of the aberrant artery by arteriography, which is also helpful to the surgeon at lobectomy.


Subject(s)
Bronchopulmonary Sequestration/diagnostic imaging , Lung Abscess/diagnostic imaging , Lung Neoplasms/diagnostic imaging , Adult , Bronchopulmonary Sequestration/surgery , Diagnosis, Differential , Female , Humans , Radiography
20.
J Cardiovasc Pharmacol ; 15(5): 776-9, 1990 May.
Article in English | MEDLINE | ID: mdl-1692938

ABSTRACT

Flecainide acetate, a class Ic antiarrhythmic agent, is eliminated to a larger extent by renal excretion and to a minor extent by the liver. In patients with impaired renal function or with elevated urinary pH, however, its elimination is dominated by hepatic metabolism. Recent evidence suggests that the in vivo metabolism of flecainide is controlled by the genetic polymorphism of the debrisoquin/sparteine type; i.e., it is a substrate of cytochrome P450IID6. We investigated the inhibitory effect of flecainide on bufuralol 1'-hydroxylation in human liver microsomes in vitro and on the metabolic dextromethorphan urinary ratio in eight healthy male volunteers. Both bufuralol and dextromethorphan are well-known substrates of cytochrome P450IID6. Microsomal bufuralol 1-hydroxylation was competitively inhibited by flecainide with an apparent Ki of 0.954 mumol/L. Moreover, a statistically significant increase in the urinary metabolic ratio (MR) of dextromethorphan/dextrorphan after 1 week of administration of oral flecainide was observed (p = 0.013) in all subjects. One individual increased the urinary MR to a value consistent with the poor metabolizer phenotype. We conclude that flecainide is a potent inhibitor of cytochrome P450IID6 in vitro and in vivo and that careful drug monitoring is required with respect to renal function, debrisoquine phenotype, and concomitant drug administration.


Subject(s)
Cytochrome P-450 Enzyme Inhibitors , Flecainide/pharmacology , Mixed Function Oxygenases/antagonists & inhibitors , Adult , Cytochrome P-450 CYP2D6 , Debrisoquin/metabolism , Dextromethorphan/blood , Dextromethorphan/urine , Ethanolamines/metabolism , Humans , In Vitro Techniques , Kinetics , Male , Microsomes, Liver/drug effects , Microsomes, Liver/enzymology , Phenotype , Sparteine/metabolism
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