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1.
J Med Econ ; 26(1): 366-375, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36905581

RESUMO

OBJECTIVE: The radiopharmaceuticals radium-223 and the pharmacy preparation 177Lu-PSMA-I&T are reimbursed in the Netherlands for metastatic castration-resistant prostate cancer (mCRPC) treatment. Although shown to be life-prolonging in patients with mCRPC, the treatment procedures associated with these radiopharmaceuticals can be challenging for both patients and hospitals. This study investigates the costs of mCRPC treatment in Dutch hospitals for currently reimbursed radiopharmaceuticals with a demonstrated overall survival benefit. METHODS: A cost model that calculated the direct medical per-patient costs of radium-223 and 177Lu-PSMA-I&T was developed, following clinical trial regimens. The model considered six 4-weekly administrations (i.e. ALSYMPCA regimen) of radium-223. Regarding 177Lu-PSMA-I&T, the model used both the VISION regimen (i.e. five 6-weekly administrations) and the SPLASH regimen (i.e. four 8-weekly administrations). Based on health insurance claims, we also estimated the coverage a hospital would receive for providing treatment. No fitting health insurance claim for 177Lu-PSMA-I&T is currently available; therefore, we calculated a break-even value for a potential health insurance claim that would exactly counterbalance the per-patient costs and coverage. RESULTS: Radium-223 administration is associated with per-patient costs of €30,905, and these costs are fully covered by the coverage a hospital receives. The per-patient costs of 177Lu-PSMA-I&T range between €35,866 and €47,546 per administration period, depending on the regimen. Current healthcare insurance claims do not fully cover the costs of providing 177Lu-PSMA-I&T: hospitals must pay €4,414-€4,922 for each patient out of their own budget. The break-even value for the potential insurance claim covering 177Lu-PSMA-I&T administration with a VISION (SPLASH) regimen is €1,073 (€1,215). CONCLUSION: This study shows that, without consideration of the treatment effect, radium-223 treatment for mCRPC leads to lower per-patient costs than treatment with 177Lu-PSMA-I&T. The detailed overview of the costs associated with radiopharmaceutical treatment provided by this study is relevant for both hospitals and healthcare insurers.


Prostate cancer is the most common form of cancer among men in the Netherlands, and its treatment is increasingly expensive. Given the limited hospital budget, it is important to consider costs in the treatment of prostate cancer. Radiopharmaceuticals are one of the multiple treatment options for metastatic prostate cancer. The current study looked at the costs of two radiopharmaceuticals, radium-223 and 177Lu-PSMA-I&T, while using multiple treatment regimens.The cost of radium-223 treatment is €30,905 per patient and is fully covered by insurance. The cost of 177Lu-PSMA-I&T treatment ranges from €35,866 to €47,546 per patient and is partially paid from the budget of the hospitals considering current reimbursement amounts. The study shows that, without consideration of the treatment effects, radium-223 treatment for prostate cancer leads to lower per-patient costs than treatment with 177Lu-PSMA-I&T. The detailed overview of the costs associated with radiopharmaceutical treatment provided by this study is relevant for both hospitals and healthcare insurers to manage prostate cancer treatment costs.


Assuntos
Custos de Medicamentos , Neoplasias de Próstata Resistentes à Castração , Compostos Radiofarmacêuticos , Humanos , Masculino , Hospitais , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/economia , Compostos Radiofarmacêuticos/economia , Compostos Radiofarmacêuticos/uso terapêutico , Resultado do Tratamento , Países Baixos
2.
Eur J Health Econ ; 24(9): 1455-1472, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36633725

RESUMO

OBJECTIVES: The aim of this study was to evaluate the cost-effectiveness of ravulizumab compared with eculizumab for the treatment of adult patients with paroxysmal nocturnal hemoglobinuria (PNH) in the Netherlands. METHODS: A cost-effectiveness analysis was conducted based on a Markov cohort model simulating the course of patients with PNH with clinical symptom(s) indicative of high disease activity, or who are clinically stable after having been treated with eculizumab for at least the past six months. Costs, quality of life, and the incremental cost-effectiveness ratio (ICER) were estimated over a lifetime horizon from a Dutch societal perspective. Several additional analyses were performed, including a one-way sensitivity analysis, a probabilistic sensitivity analysis, and scenario analysis. RESULTS: When compared with eculizumab, ravulizumab saves €266,833 and 1.57 quality adjusted life years (QALYs) are gained, resulting in a dominant ICER. Drug costs account for the majority of the total costs in both intervention groups. Cost savings were driven by the difference in total treatment costs of ravulizumab compared with eculizumab caused by the reduced administration frequency, accounting for 98% of the total cost savings. The QALY gain with ravulizumab is largely attributable to the improved quality of life associated with less frequent infusions and BTH events. At a willingness-to-pay threshold of €20,000/QALY, there is a 76.6% probability that ravulizumab would be cost-effective. CONCLUSIONS: The cost reduction and QALY gain associated with the lower rates of BTH and less frequent administration make ravulizumab a cost-saving and clinically beneficial substitute for eculizumab for adults with PNH in the Netherlands.


Assuntos
Hemoglobinúria Paroxística , Adulto , Humanos , Hemoglobinúria Paroxística/tratamento farmacológico , Análise Custo-Benefício , Qualidade de Vida , Países Baixos
3.
Graefes Arch Clin Exp Ophthalmol ; 260(4): 1083-1095, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34643793

RESUMO

PURPOSE: Although intraocular anti-vascular endothelial growth factors (anti-VEGFs) are effective as treatment of neovascular age-related macular degeneration (nAMD), the (economic) burden on the healthcare system is considerable. A treat-and-extend (T&E) regimen is associated with a lower number of injections without compromising the effectiveness and can therefore help optimise nAMD treatment. This study investigates the per-patient costs associated with nAMD treatment, when using aflibercept, bevacizumab, or ranibizumab with a T&E regimen. METHODS: In this cost-minimisation model, the per-patient costs in the Netherlands were modelled using a healthcare payers' perspective over a 3-year time horizon with the assumption that efficacy of treatments is similar. Additionally, the break-even price of the different anti-VEGFs was calculated relative to the cheapest option and injection frequency. RESULTS: The injection frequency varied from 14.2 for aflibercept to 27.4 for bevacizumab in 3 years. Nonetheless, bevacizumab remains the cheapest treatment option (€14,215), followed by aflibercept (€18,202) and ranibizumab (€31,048). The medication covers the majority of the per-patient costs for aflibercept and ranibizumab, while administration covers the majority of the per-patient costs for bevacizumab. The break-even prices of aflibercept and ranibizumab are respectively €507 and €60.58 per injection. Brolucizumab was included in the scenario analysis and was more expensive than aflibercept (€20,446). Brolucizumab should reduce to 13.8 injections over 3 years to be as costly as aflibercept. CONCLUSION: Bevacizumab is the cheapest anti-VEGF treatment. The list prices of all anti-VEGFs should reduce to be as costly as bevacizumab. Aflibercept is the second-choice treatment and so far brolucizumab is not.


Assuntos
Degeneração Macular , Receptores de Fatores de Crescimento do Endotélio Vascular , Inibidores da Angiogênese , Bevacizumab , Humanos , Injeções Intravítreas , Degeneração Macular/tratamento farmacológico , Ranibizumab , Proteínas Recombinantes de Fusão/uso terapêutico , Resultado do Tratamento , Acuidade Visual
4.
Clin Exp Dermatol ; 42(6): 607-613, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28556026

RESUMO

BACKGROUND: Cutaneous microdialysis (CM) is an ex vivo technique that allows study of tissue chemistry, including bioavailability of actual tissue concentration of unbound drug in the interstitial fluid of the body. AIM: To test the penetration and dermal bioavailability of galenic formulations of the small-molecule IP10.C8, a dual-protease inhibitor of the dipeptidyl peptidase and aminopeptidase families. METHODS: Using CM, we tested the penetration and dermal bioavailability of IP10.C8 into the dermis and subcutis of pigs, and determined the tissue concentration of IP10.C8 enzymatically, using an enzyme activity assay (substrate Gly-Pro-pNA) and high performance liquid chromatography. RESULTS: Dermal bioavailability was enhanced by using microemulsion or the addition of the penetration enhancer oleic acid to a hydroxyethylcellulose (HEC) gel formulation. Dermal bioavailability was also enhanced when galenic formulations were prepared with higher pH (7.5 vs. 6.5) or higher drug concentration (5% vs. 1%) in HEC gel. CONCLUSION: It seems possible, using CM for topical skin penetration testing in anaesthetized domestic pigs, to test the bioavailability of newly designed drugs. However, the experimental time is limited due to the anaesthesia, and is dependent on drug recovery. Validation of this technique for routine use is challenging, and more experiments are needed to validate this preclinical set-up.


Assuntos
Dipeptidil Peptidases e Tripeptidil Peptidases/antagonistas & inibidores , Microdiálise , Absorção Cutânea , Administração Cutânea , Animais , Disponibilidade Biológica , Composição de Medicamentos , Ensaios Enzimáticos , Modelos Animais , Projetos Piloto , Suínos
7.
J Eur Acad Dermatol Venereol ; 30(9): 1537-43, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27005005

RESUMO

AIMS: The aim of this pilot study was to use microdialysis to evaluate levels of Methotrexate (MTX) directly in psoriatic skin following oral or subcutaneous administration of MTX to elaborate a complete pharmacokinetic profile within the dermal skin. METHODS: Six patients with chronic plaque psoriasis on the arm undergoing treatment with MTX were included in a mono-centre clinical trial. Patients were under treatment with p.o. or s.c. MTX (7.5 and 15 mg) for at least 3 months. Interstitial fluid was collected ex vivo via dermal microdialysis from lesional or non-lesional skin and via intravenous microdialysis as well as blood serum every hour up to 10 h after methotrexate administration every hour. MTX was analysed via liquid chromatography. RESULTS: The area under the curve (AUC) of methotrexate from peripheral blood was up to four times higher than from microdiaylsis, which detection of free unbound MTX. The AUC from dialysates in psoriatic lesional skin was higher than in non-lesional psoriatic skin, and the AUC levels from i.v. microdialysis were non-significantly higher than those from lesional psoriatic skin. Pharmacokinetic profiles were individually quite different and did not primarily depend on the dose or the means (p.o. vs. s.c.) in which it was administered. CONCLUSION: Dermal microdialysis is a valid tool to evaluate levels of methotrexate in the skin of psoriasis patients. Drug levels and bioavailability of methotrexate were higher in lesional than non-lesional psoriatic skin. The individual AUC of MTX was not primarily dependent on the route or dose of administration.


Assuntos
Fármacos Dermatológicos/farmacocinética , Metotrexato/farmacocinética , Psoríase/tratamento farmacológico , Administração Oral , Adulto , Idoso , Disponibilidade Biológica , Fármacos Dermatológicos/administração & dosagem , Humanos , Injeções Subcutâneas , Metotrexato/administração & dosagem , Microdiálise , Pessoa de Meia-Idade , Psoríase/metabolismo
8.
Br J Dermatol ; 175(3): 520-30, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26914519

RESUMO

BACKGROUND: Epidermal stem cells are multipotent cells that maintain the skin epidermis. Potential markers for stem cells have been identified in mammalian skin from mouse experiments; however, it is unclear if stem cells also contribute to tumour formation in human skin. OBJECTIVES: To investigate the expression of potential stem cell markers, such as leucine-rich repeat-containing G protein-coupled receptor (Lgr) 5, Lgr6, leucine-rich repeats and immunoglobulin-like domain protein 1 (Lrig1) and cytokeratin 15 (CK15) in basal cell carcinomas and tumours of the skin appendages. METHODS: We tested 45 human basal cell carcinomas (BCCs), including superficial, nodular, adenoid, infiltrating and sclerosing types, and 38 human tumours of skin appendages, including 13 sebaceous adenomas and carcinomas, 20 eccrine sweat gland tumours and five pilomatricomas, for the expression of hair follicle stem cell markers such as Lgr5, Lrig1, CK15, ß-catenin and SRY (sex determining region Y)-box 9 (SOX9), and compared these findings with those of healthy age-matched human epidermis. RESULTS: We detected the expression of stem cell markers in all tumours tested. Regarding Lgr5, Lrig1, CK15 and SOX9, expression seemed to be lower in more aggressive tumour types, such as in the most advanced parts of infiltrating BCC, in sebaceous carcinoma and late-stage porocarcinoma, compared with less aggressive superficial or nodular BCC or early-stage porocarcinoma and sebaceous gland tumours. In aggressive, sclerosing BCC, Lrig1 and Lgr5 were downregulated but CK15, SOX9 and nuclear ß-catenin were upregulated. CONCLUSIONS: Expression of potential stem cell markers of the epidermis and hair follicles was observed in skin tumours of appendages and BCCs. However, during tumour progression, many of these markers seemed to be downregulated.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma Basocelular/metabolismo , Neoplasias Cutâneas/metabolismo , Células-Tronco/metabolismo , Regulação para Baixo/fisiologia , Epiderme/metabolismo , Doenças do Cabelo/metabolismo , Folículo Piloso/metabolismo , Humanos , Queratina-15/metabolismo , Glicoproteínas de Membrana/metabolismo , Pilomatrixoma/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Fatores de Transcrição SOX9/metabolismo , Neoplasias das Glândulas Sebáceas/metabolismo , Neoplasias das Glândulas Sudoríparas/metabolismo , Regulação para Cima/fisiologia , beta Catenina/metabolismo
11.
Oncogene ; 31(8): 992-1000, 2012 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-21765471

RESUMO

We have previously described InvEE transgenic mice in which non-dividing, differentiating epidermal cells express oncogenically activated MAPK kinase 1 (MEK1). Skin wounding triggers tumour formation in InvEE mice via a mechanism that involves epidermal release of IL-1α and attraction of a pro-tumorigenic inflammatory infiltrate. To look for potential effects on the underlying connective tissue, we screened InvEE and wild-type epidermis for differential expression of cytokines and immune modulators. We identified a single protein, CD26 (dipeptidyl peptidase-4). CD26 serum levels were not increased in InvEE mice. In contrast, CD26 was upregulated in keratinocytes expressing mutant MEK1 and in the epithelial compartment of InvEE tumours, where it accumulated at cell-cell borders. CD26 expression was increased in dermal fibroblasts following skin wounding but was downregulated in tumour stroma. CD26 activity was stimulated by calcium-induced intercellular adhesion in keratinocytes, suggesting that the upregulation of CD26 in InvEE epidermis is due to expansion of the differentiated cell layers. IL-1α treatment of dermal fibroblasts stimulated CD26 activity, and therefore epidermal IL-1α release may contribute to the upregulation of CD26 expression in wounded dermis. Pharmacological blockade of CD26, via Sitagliptin, reduced growth of InvEE tumours, while combined inhibition of IL-1α and CD26 delayed tumour onset and reduced tumour incidence. Our results demonstrate that inappropriate activation of MEK1 in the epidermis leads to changes in dermal fibroblasts that, like the skin inflammatory infiltrate, contribute to tumour formation.


Assuntos
Carcinoma de Células Escamosas/enzimologia , Dipeptidil Peptidase 4/metabolismo , Células Epiteliais/enzimologia , Expressão Gênica , Papiloma/enzimologia , Neoplasias Cutâneas/enzimologia , Células Estromais/enzimologia , Animais , Carcinoma de Células Escamosas/patologia , Células Cultivadas , Dipeptidil Peptidase 4/genética , Inibidores da Dipeptidil Peptidase IV/farmacologia , Epiderme/lesões , Epiderme/metabolismo , Epiderme/patologia , Fibroblastos/metabolismo , Humanos , Interleucina-1alfa/metabolismo , Queratinócitos , MAP Quinase Quinase 1/genética , MAP Quinase Quinase 1/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Papiloma/patologia , Pirazinas/farmacologia , Fosfato de Sitagliptina , Neoplasias Cutâneas/patologia , Triazóis/farmacologia , Regulação para Cima
12.
Clin Exp Dermatol ; 36(3): 270-2, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20659118

RESUMO

We present the case of a 79-year-old patient with extensive metastatic malignant melanoma (MM) of the scalp. Cutaneous MM of the head and neck often presents a therapeutic challenge. Radical surgical procedures and conventional chemotherapy are often unfeasible and contraindicated because of the difficult anatomy, the extent of the tumour process, and systemic toxicity. In our patient, selective intra-arterial perfusion with pegylated liposomal doxorubicin (PLD) and melphalan was performed after catheterization of both bilateral external carotid arteries with an arterial port system. PLD 4.5 mg/m(2) and melphalan (1.35 mg/m(2), followed by 2.7 mg/m(2) after reaching tolerance) were given as short-term infusions at two-weekly intervals into the right and left external carotid arteries, respectively. After eight applications with tolerable side-effects, no MM cells were detected; however, infiltrates of lymphocytes and melanophages were seen. This case suggests that intra-arterial chemotherapy may be a useful treatment for metastatic melanoma of the scalp.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias de Cabeça e Pescoço/secundário , Melanoma/secundário , Couro Cabeludo , Neoplasias Cutâneas/tratamento farmacológico , Idoso , Artéria Carótida Externa , Quimioterapia do Câncer por Perfusão Regional/métodos , Doxorrubicina/administração & dosagem , Doxorrubicina/análogos & derivados , Feminino , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Melanoma/tratamento farmacológico , Melanoma/patologia , Melfalan/administração & dosagem , Polietilenoglicóis/administração & dosagem , Neoplasias Cutâneas/patologia
13.
Dtsch Med Wochenschr ; 129(27): 1495-9, 2004 Jul 02.
Artigo em Alemão | MEDLINE | ID: mdl-15227589

RESUMO

BACKGROUND AND OBJECTIVES: Diagnosis-related groups of medical services has recently been introduced for reimbursing hospital services. The aim has been to optimize bed capacity, decrease the duration of inpatient stay and provide good follow-up medical care. This confronts hospitals with the need for closely cooperating with the referring general practitioners or specialists. METHOD: A specially structured questionnaire was sent to all those general practitioners and specialists (n=890) who had referred patients to a university department of dermatology. The response rate was 23%. The completed questionnaires were analysed with respect to criteria judged to be important in determining referral for inpatient care and the quality of medical and related service provisions. RESULTS: Especially important to the referring doctors were optimal competence of patient care, the degree of cooperation and prompt, detailed information after the patients have been discharged. CONCLUSION: This type of analysis can serve to optimize the course of diagnosis/treatment and to utilize fully the available hospital resources. Also considered are various ways in which a hospital department can, by networking with general practitioners and specialists, become a centre for providing optimal services.


Assuntos
Redes Comunitárias/normas , Dermatologia/normas , Ambulatório Hospitalar/normas , Indicadores de Qualidade em Assistência à Saúde , Encaminhamento e Consulta/normas , Competência Clínica/normas , Grupos Diagnósticos Relacionados , Alemanha , Recursos em Saúde , Hospitais Universitários/normas , Humanos , Ambulatório Hospitalar/estatística & dados numéricos , Inquéritos e Questionários
14.
Hum Gene Ther ; 12(4): 391-9, 2001 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-11242531

RESUMO

Recombinant adenoviruses expressing a therapeutic gene are currently used in clinical studies for treatment of advanced ovarian cancer. We therefore tested whether the expression level of primary (CAR) and secondary adenovirus receptors (integrins) was predictive of the efficacy of adenoviral gene transfer in ovarian cancer cells. Adenoviral transduction efficiency (ATE) was determined with an E1-deleted adenovirus type 5 expressing beta-galactosidase under a CMV promoter (AdGal). ATE was studied in relationship to the expression level of both CAR (coxsackie and adenovirus receptor) and integrins. A representative sample of 25 permanent human cell lines established from advanced ovarian cancer in our laboratory and the OV-2774 cell line were tested. Overall, ATE increased with increasing titers of AdGal. At a given titer of 50 infectious units per cell, transduction efficiency varied from 6 to 94% among the individual cell lines. All cell lines expressed CAR and integrin alpha(v)beta(5), but no relation between ATE and expression level of CAR or alpha(v)beta(5) integrin was observed. In contrast, cell lines with poor ATE, despite expressing high levels of CAR, lacked expression of integrins alpha(v)beta(3) and alpha(5)beta(1). Reconstitution of alpha(v)beta(3) integrin by reexpressing the beta(3) subunit significantly enhanced ATE of ovarian cancer cells. In ovarian cancer, neither integrins nor CAR alone appear to be potentially useful predictive markers for ATE by serotype 5 adenovirus in clinical gene therapy. A minimum level of CAR necessary for binding of adenoviruses was observed in all tested ovarian cancer cell lines. Loss of alpha(v)beta(3) integrin is frequently associated with advanced stages of ovarian cancer and can significantly reduce ATE.


Assuntos
Adenoviridae/genética , Antígenos CD/biossíntese , Integrinas/análise , Neoplasias Ovarianas/metabolismo , Glicoproteínas da Membrana de Plaquetas/biossíntese , Receptores de Vitronectina/metabolismo , Transdução Genética , Antígenos CD/genética , Western Blotting , Membrana Celular/metabolismo , Proteína de Membrana Semelhante a Receptor de Coxsackie e Adenovirus , Primers do DNA/química , Feminino , Citometria de Fluxo , Expressão Gênica , Vetores Genéticos , Humanos , Integrina beta3 , Proteínas de Neoplasias/análise , Glicoproteínas da Membrana de Plaquetas/genética , RNA Mensageiro/análise , Receptores Virais/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Tumorais Cultivadas , beta-Galactosidase/genética , beta-Galactosidase/metabolismo
16.
Pacing Clin Electrophysiol ; 14(11 Pt 2): 1803-8, 1991 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-1721179

RESUMO

Polarization artifacts that result from pacing may interfere with analysis of paced evoked responses during, e.g., automatic threshold tracking. We have developed a method for reduction of such artifacts that relies on the introduction of pacing stimuli during the refractory period of unipolar or bipolar paced captured beats after previous identification of a refractory period "template" or baseline. The refractory pacing stimuli cannot capture the heart, and thus any deviation from the template is due to polarization artifact alone. The artifact amplitude is measured and the precharge duration of the triphasic stimulus waveform is changed each time until artifact is minimized, as detected by repeated reversals in the polarity of the polarization artifact. In a series of 11 patients with unipolar and bipolar permanent pacing leads, mean initial artifact before balancing was 1.44 +/- 0.84 mV, which was reduced to 0.44 +/- 0.30 mV after balancing (P = 0.001). Initial precharge duration was 3.2 msec by design; mean final precharge duration was 3.30 +/- 0.34 msec. This algorithm is universally applicable in permanent pacing systems, as it is valid in unipolar and bipolar pacing and it does not require an intrinsic cardiac rhythm.


Assuntos
Algoritmos , Artefatos , Estimulação Cardíaca Artificial/métodos , Marca-Passo Artificial , Eletrodos Implantados , Potenciais Evocados , Humanos , Período Refratário Eletrofisiológico/fisiologia
18.
Acta Pharmacol Toxicol (Copenh) ; 46(4): 263-9, 1980 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7368944

RESUMO

The cardiac effects of supratherapeutic concentrations of two tricyclic antidepressants were studied in isolated rabbit hearts, which were perfused with a modified Krebs-Henseleit solution containing 0.25 or 0.50 micrograms ml-1 of amitriptyline or 0.28 micrograms mg-1 of clomipramine. The following parameters were continuously recorded:heart rate, amplitude and rate of contraction, coronary flow rate, myocardial oxygen consumption and ECG. The lowest concentration of amitriptyline caused a time correlated decrease (20%) in the frequency of spontaneous beating and a pronounced decrease in the amplitude (62%) and rate of cardiac contraction (58%). Maximum increases of the PQ-interval of about 46% and of the QRS-complex of about 100% were observed. At the higher amitriptyline concentration these effect further increased. Clomipramine 0.28 micrograms ml-1 also had a very pronounced and time correlated negative inotropic effect, but the effects upon the conduction velocities were substantially lesser than those produced by the equimilar concentration of amitriptyline. The compounds caused only insignificant changes in coronary flow. The oxygen consumption did not decrease in proportion to the decrease in contractility, as an expression of decreased myocardial efficiency. The effects of the drugs are discussed in relation to theri myocardial accumulation pharmacokinetics and influence upon the membraneous sodium and calcium flux and intracellular metabolism.


Assuntos
Amitriptilina/farmacologia , Clomipramina/farmacologia , Coração/efeitos dos fármacos , Hemodinâmica/efeitos dos fármacos , Amitriptilina/administração & dosagem , Animais , Clomipramina/administração & dosagem , Circulação Coronária/efeitos dos fármacos , Eletrocardiografia , Frequência Cardíaca/efeitos dos fármacos , Contração Miocárdica/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacos , Perfusão , Coelhos
19.
Acta Pharmacol Toxicol (Copenh) ; 46(3): 213-8, 1980 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7361577

RESUMO

The myocardial pharmacokinetics of amitriptyline and clomipramine were investigated in isolated rabbit hearts, which were perfused with a modified Krebs-Henseleit solution containing the equimolar concentrations 0.25 or 0.28 micrograms ml-1 of the compounds, respectively. The rate of myocardial uptake of the drugs as a function of time was indirectly followed by determinations of the concentrations of the compounds in fractional samples of the coronary output of perfusate. The time course of disposition of amitriptyline from the myocardium was similarly followed after changing from amitriptyline perfusion to perfusion with drug-free liquid. The amitriptyline accumulation and disposition processes were found to fit bi-exponential functions indicating myocardial two-compartment characteristics of the compound. Clomipramine did only exhibit one-compartment myocardial characteristics. The biological half-life of amitriptyline in the myocardium was about 37.7 min. and a pronounced cardiac accumulation of about 340 micrograms of the compound at steady state was evidenced. The myocardial half-life of clomipramine was about 106 min. and the accumulated amount at steady state was calculated to be 1055 micrograms. After amitriptyline perfusion an increase in the pharmacokinetic rate constants k10 and k12 and a decrease in the apparent central volume of distribution was observed.


Assuntos
Amitriptilina/metabolismo , Clomipramina/metabolismo , Miocárdio/metabolismo , Animais , Meia-Vida , Cinética , Perfusão , Coelhos , Fatores de Tempo
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