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1.
J Allergy Clin Immunol ; 108(5): 726-31, 2001 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-11692096

RESUMEN

BACKGROUND: It has been suggested that R-albuterol produces bronchodilation that is comparable with that of racemic albuterol (RS-albuterol) on a 4:1 dose-for-dose basis but systemic side effects on a 2:1 basis, implying better therapeutic ratio for R-albuterol. OBJECTIVE: We sought to carefully compare the bronchodilating and systemic effects of R- and RS-albuterol by using a crossover study design. METHODS: Twenty asthmatic patients (15.1%-28.7% FEV(1) reversibility) were given R-albuterol (6.25-1600 microg), S-albuterol (6.25-1600 microg), RS-albuterol (12.5-3200 microg), or placebo in a crossover, double-blind, placebo-controlled fashion. Cumulative doses were given with a Mefar dosimeter, and FEV(1), heart rate, and plasma K(+) levels were measured 20 minutes after each dose. RESULTS: Both R- and RS-albuterol produced dose-related improvement in FEV(1) and, at higher doses, increased heart rate and decreased plasma K(+) levels. Neither placebo nor S-albuterol had any significant effect. Individual estimates of the potency ratio for R-albuterol/RS-albuterol were calculated and summarized across all subjects. The geometric mean potency ratio for effects on FEV(1) was 1.9 (95% CI, 1.3-2.8), on HR of 1.9 (95% CI, 1.3-2.9), and on K(+) level of 1.7 (95% CI, 1.3-2.1). CONCLUSION: All pharmacologic effects of RS-albuterol reside with the R-enantiomer, and S-albuterol is clinically inactive. The R-albuterol/RS-albuterol potency ratios for local (FEV(1)) and systemic effects (heart rate and K(+)) are similar, suggesting a comparable therapeutic ratio for R-albuterol and RS-albuterol in asthmatic subjects.


Asunto(s)
Albuterol/química , Albuterol/uso terapéutico , Asma/tratamiento farmacológico , Broncodilatadores/química , Broncodilatadores/uso terapéutico , Adulto , Anciano , Albuterol/efectos adversos , Albuterol/farmacocinética , Asma/metabolismo , Broncodilatadores/efectos adversos , Broncodilatadores/farmacocinética , Estudios Cruzados , Relación Dosis-Respuesta a Droga , Femenino , Volumen Espiratorio Forzado/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Masculino , Persona de Mediana Edad , Potasio/sangre , Estereoisomerismo
2.
Eur J Clin Pharmacol ; 56(11): 781-91, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11294367

RESUMEN

OBJECTIVE: To investigate the potential for systemic pharmacodynamic and pharmacokinetic interactions between inhaled salmeterol and fluticasone propionate when repeat doses of the two drugs are given in combination to healthy subjects. METHODS: Twenty-eight healthy subjects received salmeterol 100 microg, salmeterol 100 microg/fluticasone propionate 500 microg and fluticasone propionate 500 microg via a Diskus dry powder inhaler twice daily for 11 days according to a randomised, double-blind, placebo-controlled, crossover design. Subjects in the placebo group also received a single dose of salmeterol 100 microg on the morning of day 10. On day 10, the systemic effects of salmeterol [on pulse rate, blood pressure, corrected QT (QTc) interval and serum potassium and glucose levels] and fluticasone propionate (on 24-h urinary cortisol and morning plasma cortisol levels) were assessed. Maximal number and affinity of lymphocyte beta2-adrenoceptors and beta2-adrenoceptor polymorphism at loci 16 and 27 were also determined. Plasma pharmacokinetics of salmeterol and fluticasone propionate were determined after the morning dose on day 10. Dosing continued on the evening of day 10 and on day 11, and on day 12 the effect of repeat-dose treatment with salmeterol and salmeterol/fluticasone propionate on the systemic effects of cumulative doses of inhaled salbutamol (up to a total dosage of 3,200 microg) was evaluated. RESULTS: All treatments were safe and well tolerated. With the exception of a higher pulse rate after repeat administration of salmeterol [66.2 beats per minute (bpm) versus 63.6 bpm], there were no significant differences between the single-dose and repeat-dose salmeterol groups. The systemic pharmacodynamic effects of inhaled salmeterol were not affected by the co-administration of fluticasone propionate. Eleven days of treatment with salmeterol induced tachyphylaxis to the systemic effects of cumulative doses of salbutamol; however, co-administration of fluticasone propionate did not affect the response to salbutamol. Fluticasone propionate reduced 24-h urinary cortisol excretion (22.4 microg compared with 48.6 microg with placebo), but this was unaffected by the co-administration of salmeterol. Morning plasma cortisol levels were not reduced compared with placebo. There was no significant treatment effect on lymphocyte beta2-adrenoceptors and no correlation of beta2-adrenoceptor polymorphism at loci 16 and 27 with the development of tachyphylaxis. Salmeterol plasma concentrations were measurable only during the first half-hour after dosing. Co-administration of fluticasone propionate did not affect the peak plasma concentration (Cmax) of salmeterol. For fluticasone propionate, there were no statistically significant differences between salmeterol/fluticasone propionate and fluticasone propionate with respect to Cmax, plasma concentration at the end of the dosing interval (Ct), terminal elimination half-life (t1/2) or time to Cmax (tmax). The area under the concentration-time curve within a dosing interval (AUCt) for fluticasone propionate after inhalation of salmeterol/fluticasone propionate was statistically significantly higher (about 8%) than after inhalation of fluticasone propionate alone (P=0.0135). However, the 90% confidence intervals (CIs) for the AUCt and Cmax ratios for the two treatments were within the accepted limits for bioequivalence (1.03, 1.13 and 0.97, 1.12, respectively). CONCLUSION: These results in healthy subjects indicate that there is no systemic pharmacodynamic or pharmacokinetic interaction between inhaled salmeterol and fluticasone propionate when given in combination.


Asunto(s)
Corticoesteroides/farmacología , Albuterol/análogos & derivados , Albuterol/farmacología , Androstadienos/farmacología , Broncodilatadores/farmacología , Receptores Adrenérgicos beta/efectos de los fármacos , Administración por Inhalación , Corticoesteroides/farmacocinética , Adulto , Albuterol/farmacocinética , Análisis de Varianza , Androstadienos/farmacocinética , Área Bajo la Curva , Presión Sanguínea/efectos de los fármacos , Broncodilatadores/farmacocinética , Estudios Cruzados , Método Doble Ciego , Interacciones Farmacológicas , Femenino , Fluticasona , Semivida , Humanos , Masculino , Persona de Mediana Edad , Receptores Adrenérgicos beta/genética , Xinafoato de Salmeterol
3.
Br J Clin Pharmacol ; 49(1): 15-22, 2000 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10606833

RESUMEN

Aims To establish whether enantioselective metabolism of racemic (rac )-salbutamol occurs in the lungs by determining its enantiomeric disposition following inhalation, in the absence and presence of oral charcoal, compared with that following the oral and intravenous routes. Methods Fifteen healthy subjects (eight male) were randomized into an open design, crossover study. Plasma and urine salbutamol enantiomer concentrations were measured for 24 h following oral (2 mg) with or without oral charcoal (to block oral absorption), inhaled (MDI; 1200 microg) with or without oral charcoal and intravenous (500 microg) rac-salbutamol. Systemic exposure (plasma AUC(0,infinity) and urinary excretion (Au24h ) of both enantiomers were calculated, and relative exposure to (R)-salbutamol both in plasma (AUC(R)-/AUC(S)- ) and urine (Au(R)-/Au(S)- ) was derived for each route. Relative exposure after the inhaled with charcoal and oral routes were compared with the intravenous route. Results AUC(R)-/AUC(S)- [geometric mean (95% CI)] was similar following the intravenous [0.32 (0.28, 0.36)] and inhaled with charcoal rates [0.29 (0.24, 0.36); P=0.046], but was far lower following oral dosing [0.05 (0.03, 0.07); P<0.001]. Similar results were found when relative exposure was analysed using Au24h. Conclusions These results show no evidence of significant enantioselective presystemic metabolism in the lungs, whilst confirming it in the gut and systemic circulation, indicating that the (R)- and (S)-enantiomers are present in similar quantities in the airways following inhaled rac-salbutamol.


Asunto(s)
Albuterol/farmacocinética , Broncodilatadores/farmacocinética , Pulmón/metabolismo , Administración por Inhalación , Administración Oral , Adulto , Albuterol/administración & dosificación , Albuterol/química , Antídotos/farmacología , Área Bajo la Curva , Broncodilatadores/administración & dosificación , Broncodilatadores/química , Carbón Orgánico/farmacología , Estudios Cruzados , Femenino , Semivida , Humanos , Inyecciones Intravenosas , Masculino , Estereoisomerismo
4.
Clin Ter ; 147(12): 653-72, 1996 Dec.
Artículo en Italiano | MEDLINE | ID: mdl-9296925

RESUMEN

The authors highlight the essential role of pharmacovigilance and the need for a simple, efficient and low-cost system of adverse reaction (AR) reporting which could cover the whole population and all marketed drugs, and suggest that the only one presently viable is based on spontaneous reporting. To support their proposal the authors provide a definition of AR and of the different monitoring system, and list as many drugs as possible to find in the literature that have been associated with a specific AR, together with the active molecule, the therapeutic indication, the features of the AR and the regulatory actions (withdrawal from the market, restriction of use). Moreover, by describing the "history" behind some of these drugs the authors highlight the contribution that pharmacovigilance and spontaneous reporting have had to the development of regulations for approval and marketing of new drugs. It is also highlighted how some of these unexpected events (thalidomide, DES) have had a significant and important contribution to pharmacological and toxicological knowledge.


Asunto(s)
Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos , Vigilancia de Productos Comercializados , Relación Dosis-Respuesta a Droga , Humanos , Italia , Preparaciones Farmacéuticas/administración & dosificación , Vigilancia de Productos Comercializados/estadística & datos numéricos
5.
Clin Ter ; 147(11): 595-8, 1996 Nov.
Artículo en Italiano | MEDLINE | ID: mdl-9264914

RESUMEN

Here, the authors address the question whether the administration of placebo, in clinical trials of drugs to be registered or already registered, is ethically acceptable and/or scientifically useful. An important issue, particularly in view of the different opinions emerging in the international scientific community. Since many diseases are already treatable with established therapies and drugs, clinical trials should be performed mainly with placebo containing the appropriate active compound, in agreement with the Helsinki declaration. Active placebo should be employed when slightly modified compounds are tested and when trials are in phase 2/b, 3 or 4. The use of active placebo in these settings would be more correct from a scientific, ethical and economical point of view.


Asunto(s)
Ensayos Clínicos como Asunto/normas , Evaluación de Medicamentos/normas , Ética Médica , Placebos/uso terapéutico , Comités de Ética , Declaración de Helsinki , Humanos
6.
Br J Clin Pharmacol ; 41(6): 539-42, 1996 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-8799519

RESUMEN

1. Fluticasone propionate (FP) is a potent glucocorticoid used in the treatment of asthma. Prior to reporting the pharmacokinetics following the inhaled and oral routes, the pharmacokinetics need to be established following intravenous dosing. The present study determines the intravenous pharmacokinetics of FP, using non-compartmental analysis, in healthy male subjects over the 250 to 1000 micrograms dose range. 2. The pharmacokinetics of FP can be regarded as being linear over this dosing range. FP was extensively distributed within the body (Vss 3181), rapidly cleared (CL 1.1 l min-1) with a terminal elimination half-life of 7.8 h and a mean residence time of 4.9 h. 3. In order that future pharmacokinetic/pharmacodynamic and other modelling can be carried out, the plasma concentration-time profiles were parameterized using a model based on sums of exponentials, the appropriateness of this model was justified as the secondary kinetic parameters from the model were similar to those obtained using non-compartmental analysis.


Asunto(s)
Androstadienos/farmacocinética , Antiasmáticos/farmacocinética , Adulto , Androstadienos/administración & dosificación , Androstadienos/sangre , Antiasmáticos/administración & dosificación , Antiasmáticos/sangre , Método Doble Ciego , Fluticasona , Humanos , Infusiones Intravenosas , Masculino
7.
Clin Ter ; 147(3): 131-44, 1996 Mar.
Artículo en Italiano | MEDLINE | ID: mdl-8767980

RESUMEN

Given that pharmacokinetic data are mostly derived from studies in animals and healthy subjects, the authors highlight how diseases can modify one or more of its phases: absorption, distribution, metabolism and elimination (ADME). Although theoretically all diseases can modify these phases, the authors believe it worth and relevant to focus the discussion on major diseases for which information is available and which are frequent in the population and with the potential to affect more phases, i.e. cardiac, hepatic and renal failure. Therefore, the aim of the paper is to update the data available and to remind that the incidence of adverse reactions to drugs due to changes in their pharmacokinetics is frequent and often serious in these diseases.


Asunto(s)
Preparaciones Farmacéuticas , Farmacocinética , Cardiopatías/fisiopatología , Humanos , Enfermedades Renales/fisiopatología , Hepatopatías/fisiopatología
8.
Clin Ter ; 146(10): 555-75, 1995 Oct.
Artículo en Italiano | MEDLINE | ID: mdl-8590558

RESUMEN

Published clinical observations underline the difficulty of defining with epidemiological studies the effects that chemicals such as drugs, illicit substances environmental and workplace pollutants might have on the offspring through the male parent. The Authors highlight how defining this issue might help both guide preclinical research and evaluate correctly clinical observations which are often difficult to interpret based only on observations in the female parent. Clinical research already available shows that some chemicals are able to modify fertility by acting either at the neuroendocrine level or on the testis. However, it is more difficult to identify and quantify the potential damage to the offsprings during the different phases of pregnancy and postnatal life. Finally, the Authors discuss the parameters that should be considered to obtain an algorithm for evaluating the reproductive risk in males, along the lines of the risk for the embryo and fetus due to the use of drugs during pregnancy. Moreover, it is suggested that among the unwanted effects of drugs and pollutants, those related to the different components and phases of the male reproductive function be reported also in relation to the patient's age.


Asunto(s)
Reproducción/efectos de los fármacos , Contaminantes Ambientales/farmacología , Femenino , Feto/efectos de los fármacos , Genitales Masculinos/anatomía & histología , Genitales Masculinos/fisiología , Humanos , Masculino , Sistemas Neurosecretores/fisiología , Embarazo/efectos de los fármacos , Espermatozoides
9.
Drug Metab Dispos ; 23(8): 832-9, 1995 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-7493550

RESUMEN

HFA134a (1,1,1,2-tetrafluoroethane) is a nonozone-depleting candidate to replace the chlorofluorocarbons used as propellants in metered-dose inhalers (MDIs) for pharmaceuticals that are widely used in the treatment of respiratory tract disease. As a means for ensuring the safety of such a compound for human use, it is necessary to establish that there is no excessive or unexpected accumulation in the body and in selected regions. A sensitive whole-body gamma-counting technique has been used with 18F-labeled HFA134a to measure the whole-body and regional absorption, distribution, and retention of HFA134a after administration in humans by single-breath inhalation. In seven healthy subjects, labeled HFA134a was rapidly eliminated by ventilation during the first few minutes, with an average of 9.6% of the radioactivity retained in the body at 5 min. This radioactivity cleared with an apparent terminal half-life of 1.5-4.2 hr to leave, on average, < 1% of the administered dose (< 750 micrograms, approximately 0.2 microCi) retained in the body at 5.8 hr. Disposition of radioactivity was independent of the position of label. Thus, there was no evidence of any significant degradative metabolism. On average, only 0.0056% of the administered dose appeared in the urine within the first 2 hr. Later samples contained no significant radioactivity. Inhaled HFA134a first distributed to all regions of the body and then cleared without evident accumulation in any specific region.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Propelentes de Aerosoles/farmacocinética , Obstrucción de las Vías Aéreas/metabolismo , Hidrocarburos Fluorados/farmacocinética , Administración por Inhalación , Adulto , Propelentes de Aerosoles/administración & dosificación , Radioisótopos de Flúor , Semivida , Humanos , Hidrocarburos Fluorados/administración & dosificación , Masculino , Persona de Mediana Edad , Nebulizadores y Vaporizadores , Distribución Tisular , Recuento Corporal Total
10.
Thorax ; 50(6): 679-81, 1995 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-7638815

RESUMEN

BACKGROUND: Metered dose inhalers for the treatment of asthma use chlorofluorocarbons as propellants. These face an international ban due to their effect on the ozone layer. Salmeterol has been reformulated using the non-chlorinated propellant Glaxo inhalation grade HFA134a. METHODS: The safety, tolerability and systemic pharmacodynamic activity of the salmeterol/HFA134a inhaler, the current salmeterol inhaler, and placebo (HFA134a) were compared in 12 healthy volunteers in a double blind, randomised crossover study using a cumulative dosing design. RESULTS: Safety and tolerability were similar and the response was related to the dose over the range used (50-400 micrograms) with both salmeterol inhalers. The salmeterol/HFA134a inhaler showed no differences from the current inhaler for pulse rate, blood pressure, tremor, QTc interval, and plasma glucose levels. The salmeterol/HFA134a inhaler had significantly less effect on plasma potassium levels. CONCLUSIONS: In healthy volunteers the salmeterol/HFA134a inhaler is at least as safe and well tolerated as the current salmeterol inhaler, and has similar systemic pharmacodynamic activity.


Asunto(s)
Agonistas Adrenérgicos beta/farmacocinética , Propelentes de Aerosoles/farmacocinética , Albuterol/análogos & derivados , Broncodilatadores/farmacocinética , Hidrocarburos Fluorados/farmacocinética , Administración por Inhalación , Agonistas Adrenérgicos beta/efectos adversos , Adulto , Albuterol/efectos adversos , Albuterol/farmacocinética , Broncodilatadores/efectos adversos , Estudios Cruzados , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Humanos , Masculino , Potasio/sangre , Pulso Arterial/efectos de los fármacos , Xinafoato de Salmeterol
11.
Clin Ter ; 146(2): 99-116, 1995 Feb.
Artículo en Italiano | MEDLINE | ID: mdl-7789079

RESUMEN

The authors discuss the possibilities of drug interference with the reproductive system and especially during various stages of pregnancy: from the sequence of neurochemical events that condition the release of pituitary gonadotrophines at the level of the central nervous system to late events that may occur during development. After listing the periods of risk, drug-induced changes in the conceptus are illustrated on the basis of data registered in the literature. In this context, it is stressed that the dysmorphogenic effect is limited to the period of differentiation and organogenesis whereas it is becoming more and more obvious that drugs may also have variable effects on other stages of pregnancy where frequently they have specific pharmacodynamic actions on the fetus. The knowledge of these effects may be useful in order to avoid untoward actions on pregnancy or on embryo, fetus, neonate or postnatal development, but may also create a basis for in utero drug treatments of fetal pathologies.


Asunto(s)
Desarrollo Embrionario y Fetal/efectos de los fármacos , Embarazo/efectos de los fármacos , Sistema Nervioso Central/efectos de los fármacos , Implantación del Embrión/efectos de los fármacos , Femenino , Humanos , Sistema Hipotálamo-Hipofisario/efectos de los fármacos , Recién Nacido , Folículo Ovárico/efectos de los fármacos , Ovulación/efectos de los fármacos , Factores de Riesgo
12.
J Aerosol Med ; 8 Suppl 1: S35-9, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-10150494

RESUMEN

The safety, tolerability and pharmacokinetics of the chlorine-free propellant HFA134a were assessed in healthy subjects after single and repeat doses. Absorption and disposition were investigated in healthy subjects and severe chronic obstructive pulmonary disease (COPD) patients using labelled HFA134a. There were no clinically significant changes in vital signs, ECG, pulmonary function tests and laboratory parameters measured. No serious adverse events were reported. In both subjects and patients HFA134a was mainly eliminated by exhalation within the first few minutes after administration and was distributed throughout the body with no obvious accumulation in any specific region. HFA134a was rapidly absorbed after inhalation with dose-related blood concentrations which declined rapidly after dosing (t1/2 = 31 min). Metabolism was not a significant route of elimination of HFA134a. Studies were also performed with salmeterol and salbutamol MDIs reformulated with HFA134a. The results showed that these MDIs were safe and well tolerated in healthy subjects and gave a similar pharmacodynamic response to the current MDIs.


Asunto(s)
Albuterol/análogos & derivados , Albuterol/farmacología , Broncodilatadores/farmacología , Hidrocarburos Fluorados/farmacología , Albuterol/administración & dosificación , Albuterol/farmacocinética , Broncodilatadores/administración & dosificación , Broncodilatadores/farmacocinética , Relación Dosis-Respuesta a Droga , Evaluación de Medicamentos , Humanos , Hidrocarburos Fluorados/administración & dosificación , Hidrocarburos Fluorados/farmacocinética , Masculino , Nebulizadores y Vaporizadores , Xinafoato de Salmeterol
13.
Clin Ter ; 138(5-6): 189-98, 1991.
Artículo en Italiano | MEDLINE | ID: mdl-1836166

RESUMEN

The availability of new and more active drugs as well as the progress in emergency medicine have made it possible to deal in new ways with the therapy and management of hypertensive crises. The more aggressive character of this treatment leads us to reconsider the risk/benefit ratio also on the basis of changes brought about by the drugs used in the compensatory cardio-vascular equilibria that have become established in the course of the disease, as well as the possibility, that rapid and intensive pressure reductions bring about phenomena of brain hypoxia to the extent of drug syncope and brain damage. After analyzing phenomena of adaptation of brain circulation to the hypertensive disease, the authors discuss risk factors of therapeutic choices in relation to the mechanism of action of the drugs available and used, to different clinical situations and to the patient's age.


Asunto(s)
Antihipertensivos/uso terapéutico , Circulación Cerebrovascular , Hipertensión/tratamiento farmacológico , Presión Sanguínea , Urgencias Médicas , Homeostasis , Humanos , Hipertensión/fisiopatología
14.
Ann Ostet Ginecol Med Perinat ; 111(3): 159-73, 1990.
Artículo en Italiano | MEDLINE | ID: mdl-2275511

RESUMEN

Drug prescription in pregnancy for the treatment of maternal diseases and the first attempts to obtain therapeutic effects even on the product of conception make necessary to know the pharmacokinetics of drugs in pregnancy. The Authors discuss how changes of physiological maternal parameters and the presence of the placenta and of the foetus can affect drug pharmacokinetics in a clinically important way. The possibility that the unique multicompartmental structure of the maternal-placental-foetal unit can "trap" drugs in the foetus is highlighted. Methodological, ethical and legal problems make the acquisition of data on these changes difficult, but their knowledge is needed in order to prevent adverse and toxic effects both in the pregnant woman and in the foetus and to attempt a therapy of foetus diseases in intrauterine life.


Asunto(s)
Farmacocinética , Embarazo/metabolismo , Líquido Amniótico/metabolismo , Femenino , Feto/metabolismo , Edad Gestacional , Humanos , Intercambio Materno-Fetal , Placenta/metabolismo
15.
Eur J Clin Pharmacol ; 39(6): 565-8, 1990.
Artículo en Inglés | MEDLINE | ID: mdl-1982761

RESUMEN

The bronchodilating activity and tolerability of broxaterol and salbutamol administered by pressurized metered dose inhalers have been compared in 9 adult patients with bronchial asthma and clinically stable and reversible bronchospasm. Placebo was used as a control. On 3 different days broxaterol and salbutamol in cumulative doses of 100, 200 and 400 micrograms and placebo were administered every 30 min according to a double-blind, Latin-square design. After each dose of broxaterol and salbutamol the increases in FVC and FEV1 were always significantly larger than after placebo. Broxaterol at the doses tested induced a bronchodilator response which depended on the dose according to a relation not significantly different from a straight line, and with a potency at least comparable to that of salbutamol. The tolerability of the two drugs was good: only in 1 patient were slight tremors observed after the highest dose of each drug. The bronchodilating activity and the tolerability of broxaterol were not significantly different from those of salbutamol at the same doses.


Asunto(s)
Agonistas Adrenérgicos beta/administración & dosificación , Albuterol/administración & dosificación , Isoxazoles/administración & dosificación , Administración por Inhalación , Agonistas Adrenérgicos beta/farmacología , Adulto , Aerosoles , Albuterol/farmacología , Presión Sanguínea/efectos de los fármacos , Broncodilatadores/farmacología , Relación Dosis-Respuesta a Droga , Tolerancia a Medicamentos , Femenino , Volumen Espiratorio Forzado/efectos de los fármacos , Humanos , Isoxazoles/farmacología , Masculino , Persona de Mediana Edad , Pulso Arterial/efectos de los fármacos , Capacidad Vital/efectos de los fármacos
16.
Arzneimittelforschung ; 39(3): 382-6, 1989 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-2757663

RESUMEN

The plasma pharmacokinetics of oral acetylcysteine(N-acetylcysteine, NAC) after the administration of single 600 mg and repeated 200 mg doses and the relative bioavailability of the two regimens were studied in 12 adult subjects. On two different occasions in a cross-over, balanced fashion the subjects were administered orally either a single dose of NAC 600 mg as effervescent tablets or 4 repeated doses of NAC as granules in sachets at the regimen of 200 mg t.i.d. Venous blood samples were obtained just before dosing and 20, 40 min, 1, 1.5, 2, 3, 4, 6, 8, 10 and 12 h after the administration of NAC 600 mg; with the 1st, the 2nd and the 4th doses of NAC 200 mg samples were taken just before dosing and after 20, 40 min, 1, 1.5, 2, 3, 4, 6 and 8 h, the last sampling after the 1st dose being the one before the 2nd dose. A detailed description of the assaying methods of NAC is given in the text. As indexes of bioavailability Cmax' tmax and AUC of NAC plasma concentrations were considered and MRT was taken as an estimate of its persistence in plasma. NAC was quickly absorbed without any significant difference in tmax among the doses. With the 600 mg dose Cmax' AUC and MRT were greater than with a single 200 mg dose; after summing up the values of these parameters for the 200 mg doses no significant differences were observed in comparison to the single 600 mg dose in Cmax and AUC, while MRT resulted significantly higher.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Acetilcisteína/farmacocinética , Acetilcisteína/sangre , Acetilcisteína/orina , Administración Oral , Adulto , Disponibilidad Biológica , Femenino , Cromatografía de Gases y Espectrometría de Masas , Humanos , Inyecciones Intravenosas , Masculino
17.
Int J Clin Pharmacol Ther Toxicol ; 26(11): 544-51, 1988 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-3243658

RESUMEN

The pharmacokinetics of ibopamine after single and multiple dosing was studied in 20 patients with congestive heart failure (CHF) of NYHA functional class II. Ibopamine 100 mg was given 3 times a day for 7 days in 6 patients and for 30 days in the other 14 patients. Plasma pharmacokinetics of total (mainly conjugated) and free epinine was studied after the first dose and on the 3rd, 7th and 30th days of treatment. The urinary recoveries of total epinine, HVA and DOPAC were measured in 5 patients for 24 h after ibopamine ingestion on the 1st and 30th days. Plasma pharmacokinetics of ibopamine did not vary during the repeated administration of the drug. In the course of the treatment, total epinine elimination t1/2 showed no significant variations. The build-up of Cmax, Cmin and AUC of total epinine observed after multiple dosing was as expected on the basis of the interval adopted between the doses of ibopamine and of the elimination t1/2 of total epinine. Pharmacokinetic parameters of free epinine did not show significant variations during the course of the treatment. The amounts of HVA and DOPAC recovered in urine on the 1st and 30th days of treatment were similar while the amount of total epinine was greater on the 30th day, the increment mainly reflecting a partial carry over of the less rapidly excreted conjugated epinine from the last previous doses. The results obtained for free epinine plasma levels and for the urinary recoveries of ibopamine metabolites thus indicated that no saturation of the enzymes involved in ibopamine metabolism occurred.


Asunto(s)
Desoxiepinefrina/análogos & derivados , Dopamina/análogos & derivados , Insuficiencia Cardíaca/tratamiento farmacológico , Anciano , Desoxiepinefrina/administración & dosificación , Desoxiepinefrina/sangre , Desoxiepinefrina/farmacocinética , Esquema de Medicación , Femenino , Insuficiencia Cardíaca/sangre , Humanos , Masculino , Persona de Mediana Edad
18.
Arzneimittelforschung ; 38(8): 1175-80, 1988 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-2904270

RESUMEN

The pharmacokinetics of ibopamine was studied after single dose and after single and multiple dosing. The studies after single dose were conducted in normal subjects (NS) and in patients with congestive heart failure (CHF) of NYHA functional classes II, III and IV, in patients with chronic renal impairment (CRI), with hepatic cirrhosis (HC) and in elderly patients. Furthermore, ibopamine-quinidine pharmacokinetic interaction and the effects of food on plasma kinetics were evaluated in NS. The studies after single and multiple dosing were conducted in CHF patients. The effects were also studied of chronic oral ibopamine treatment on the pharmacokinetics of digoxin after chronic oral dosing and of treatment with digoxin on ibopamine pharmacokinetics. Ibopamine appears to be rapidly and extensively absorbed, quickly hydrolyzed to epinine and then excreted mainly through the kidneys either after being sulpho-conjugated or oxidized to homovanillic acid and 3,4-dihydroxyphenylacetic acid. Epinine is thought to be the therapeutically active moiety of the drug. In patients with CHF epinine pharmacokinetics does not depend on the NYHA functional class, and it falls within the same area as that in NS; the pharmacokinetics of epinine does not vary during the repeated administration of the drug for one month. In patients with CHF the pharmacokinetic data do not suggest the need to adjust the dose according to the NYHA functional class. In patients with CRI the pharmacokinetics of epinine does not vary with the degree of renal impairment. In HC patients AUC and Cmax of epinine seem to be higher than in NS; in these patients a higher amount of epinine is excreted into urine.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Desoxiepinefrina/análogos & derivados , Dopaminérgicos/farmacocinética , Dopamina/análogos & derivados , Vasodilatadores/farmacocinética , Absorción , Administración Oral , Adulto , Anciano , Anciano de 80 o más Años , Disponibilidad Biológica , Fenómenos Químicos , Química , Desoxiepinefrina/administración & dosificación , Desoxiepinefrina/farmacocinética , Digoxina/farmacocinética , Dopaminérgicos/administración & dosificación , Interacciones Farmacológicas , Femenino , Alimentos , Insuficiencia Cardíaca/metabolismo , Humanos , Fallo Renal Crónico/metabolismo , Cirrosis Hepática/metabolismo , Masculino , Persona de Mediana Edad , Quinidina/farmacocinética , Vasodilatadores/administración & dosificación
19.
Int J Clin Pharmacol Ther Toxicol ; 26(2): 105-12, 1988 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-3410586

RESUMEN

The kinetics of ibopamine, the 3,4-diisobutyryl ester of N-methyldopamine (epinine), was assessed in 27 patients with congestive heart failure (CHF) and 8 healthy normal subjects (NS). Nine patients were in functional class IV according to the NYHA definition, 9 in class III and 9 in class II. Ibopamine was administered at a single oral dose of 100 mg. Epinine, both free and total (mainly conjugated), plasma concentrations and urinary recoveries of total epinine, HVA and DOPAC were studied. The results showed that ibopamine kinetics is not substantially different in CHF patients and in NS. In both groups the absorption of the drug was equally prompt and elevated. Mean Cmax, tmax and AUC infinity values of total epinine in CHF patients did not differ significantly from those in NS. In CHF patients t 1/2 of total epinine was significantly higher than in NS (4.1 +/- 0.2 h vs 3.1 +/- 0.2 h, mean +/- SE). Mean Cmax, tmax, AUCt and MRT values of free epinine in CHF patients were not significantly different from those in NS. The urinary recovery of the 3 metabolites considered together was comparable in CHF patients and in NS. The mean +/- SE total urinary recoveries in the 24 h after dosing, expressed as percentages of the administered dose, were 60 +/- 3 in CHF patients and 69 +/- 4 in NS. Conjugated epinine in urine was found to be constituted by 3-O-sulfate (84%) and 4-O-sulfate (16%).


Asunto(s)
Desoxiepinefrina/análogos & derivados , Dopamina/análogos & derivados , Insuficiencia Cardíaca/metabolismo , Vasodilatadores/farmacocinética , Administración Oral , Adulto , Anciano , Cromatografía Líquida de Alta Presión , Desoxiepinefrina/administración & dosificación , Desoxiepinefrina/farmacocinética , Femenino , Semivida , Humanos , Masculino , Persona de Mediana Edad , Vasodilatadores/administración & dosificación
20.
Int J Clin Pharmacol Ther Toxicol ; 26(2): 98-104, 1988 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-3410592

RESUMEN

The pharmacokinetics of a single oral dose of ibopamine 100 mg were studied in 15 patients with various degrees of chronic renal impairment (CRI) and in 8 subjects with normal renal function and of comparable age, taken as a control group. Plasma total (mainly conjugated) and free epinine and urinary metabolites (total epinine, HVA and DOPAC) were measured. Both total and free epinine were detectable at the earliest sampling time (15 min) in CRI patients and in normal subjects, thus confirming the promptness of ibopamine absorption. Free epinine pharmacokinetic parameters did not show any appreciable differences among the groups with different degrees of renal impairment, and no statistically significant differences were observed between normal subjects and CRI patients. Progressive renal impairment was associated with higher Cmax, longer t1/2 and larger AUC infinity of total epinine, and with reduced urinary elimination of total epinine and metabolites. Statistically significant differences (p less than 0.01) in Cmax/70 kg, t1/2, and AUC infinity/70 kg of total epinine were found between normal subjects and patients with mild renal impairment. No statistically significant differences were observed in 24-h urinary recoveries of both total epinine and metabolites between normal subjects and patients with mild renal impairment. No adverse effects were experienced during the course of the study. As the kinetics of ibopamine's active moiety, free epinine, were not apparently altered by chronic renal failure, adjustment of its dosage should not be necessary in renal diseases.


Asunto(s)
Desoxiepinefrina/análogos & derivados , Dopamina/análogos & derivados , Fallo Renal Crónico/metabolismo , Vasodilatadores/farmacocinética , Adolescente , Adulto , Anciano , Desoxiepinefrina/farmacocinética , Desoxiepinefrina/orina , Femenino , Semivida , Humanos , Fallo Renal Crónico/orina , Masculino , Persona de Mediana Edad , Vasodilatadores/orina
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