RESUMEN
We studied the disposition of inhaled salbutamol in adolescents with cystic fibrosis (CF) and compared it with the pharmacokinetics of the drug given by the intravenous and inhaled routes in healthy adults. After inhalation of salbutamol, CF patients had a significantly larger area under the concentration-time curve derived from amounts of drug in the systemic circulation. The differences in serum concentration of salbutamol were not reflected in differences in change of heart rate. We conclude that the rate and extent of pulmonary absorption of inhaled salbutamol in patients with CF differ from those in healthy adults.
Asunto(s)
Albuterol/farmacocinética , Fibrosis Quística/metabolismo , Administración por Inhalación , Adolescente , Adulto , Albuterol/administración & dosificación , Albuterol/sangre , Disponibilidad Biológica , Fibrosis Quística/tratamiento farmacológico , Humanos , Valores de ReferenciaAsunto(s)
Albuterol/uso terapéutico , Fibrosis Quística/tratamiento farmacológico , Metabolismo Energético/efectos de los fármacos , Administración por Inhalación , Adolescente , Adulto , Albuterol/administración & dosificación , Albuterol/sangre , Fibrosis Quística/metabolismo , Femenino , Humanos , Masculino , Factores de TiempoRESUMEN
Twelve newborn infants were given morphine intravenously for postoperative analgesia. They received a continuous infusion of 6.2 to 40 micrograms/kg/hr for 9 to 105 hours (mean +/- SEM 59.5 +/- 10.2 hours); in four the infusion was preceded by a loading dose of 50 to 100 micrograms/kg. Morphine plasma concentrations correlated with the rate of infusion, but with large variability. There was a tendency for plasma morphine concentrations to decrease in some patients receiving a constant infusion rate, suggesting improvement in morphine clearance rate. Elimination half-life of morphine (13.9 +/- 6.4 hours) was significantly longer than in older children and adults (about 2 hours). Similarly, morphine concentrations in neonates receiving 20 micrograms/kg/hr for 24 hours were three times higher (52 +/- 31 ng/ml) than in older children receiving the same schedule. Two infants who received 32 and 40 micrograms/kg/hr, respectively, developed generalized seizures. Because of the apparently greater sensitivity to morphine and the lower elimination rate in newborn infants, the infused dose should not exceed 15 micrograms/kg/hr.