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- Petersen, Astrid H., et al.
(författare)
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The effect of terbutaline on the absorption of pulmonary administered insulin in subjects with asthma
- 2010
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Ingår i: British Journal of Clinical Pharmacology. - : Wiley. - 1365-2125 .- 0306-5251. ; 69:3, s. 271-278
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Tidskriftsartikel (refereegranskat)abstract
- center dot People with mild and moderate asthma have been shown to absorb less inhaled insulin than healthy subjects. center dot In people with moderate asthma, the administration of a bronchodilator before inhalation of insulin has been shown to lead to increased uptake of inhaled insulin compared with no prior administration of bronchodilator. WHAT THIS STUDY ADDS center dot This study is the first to show that in people with asthma, reduction of bronchoconstriction leads to increased absorption of inhaled insulin. center dot This study illustrates that due to the effect of terbutaline on glucose metabolism, the effect of insulin on plasma glucose is complex when terbutaline is administered concomitantly. AIM To investigate the effect of prior administration of a bronchodilator on the absorption of inhaled insulin in people with asthma treated with inhaled corticosteroids. METHODS A single-centre, randomized, open-label, two-period cross-over trial was carried out in 41 nondiabetic subjects with asthma treated with inhaled steroids, with reversible bronchoconstriction (Rev+; n = 25) or without reversible bronchoconstriction (Rev-; n = 16). A dose of 0.10 U kg-1 inhaled human insulin was administered on each dosing day with or without prior administration of the bronchodilator terbutaline (in random order). RESULTS Prior administration of terbutaline led to a 44% increase in absorption of insulin over 6 h for the Rev+ group compared with no prior administration of bronchodilator [ratio (95% confidence interval) 1.44 (1.13, 1.82), P = 0.004], whereas no effect was seen for the Rev- or the whole group. The maximum insulin concentration (C-max) increased by 34% for the Rev+ group (P = 0.018) and 17% for the whole group (P = 0.046), whereas no significant effect of prior terbutaline administration was seen for Rev-. The time to C-max was not significantly different for the Rev+ group, whereas it was approximately 30% longer after bronchodilator administration for the Rev- group (P = 0.044) and the whole group (P = 0.032). CONCLUSIONS In people with asthma and reversible bronchoconstriction, the administration of a bronchodilator prior to administration of inhaled insulin led to increased absorption of insulin, whereas no effect on insulin absorption in subjects without significant reversibility could be detected.
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- Bogason, Alex, et al.
(författare)
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Inverse relationship between leukaemic cell burden and plasma concentrations of daunorubicin in patients with acute myeloidleukaemia
- 2011
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Ingår i: British Journal of Clinical Pharmacology. - : Wiley. - 0306-5251 .- 1365-2125. ; 71:4, s. 514-521
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Tidskriftsartikel (refereegranskat)abstract
- center dot In vitro studies show that daunorubicin (DNR) cytotoxicity decreases with increasing cell density because of a high cellular uptake and depletion of drug in the medium. center dot It is not known whether such an effect also occurs in vivo. WHAT THIS STUDY ADDS center dot We have shown that a large leukaemic cell burden lowers the plasma concentration of DNR in patients with acute myeloid leukaemia. center dot Our analysis supports that a large leukaemic cell burden increases the central volume of distribution for DNR. center dot Our study indicates that a dose adjustment of DNR may be of importance in acute myeloid leukaemia patients with high white blood cell counts. AIMS It has been shown that the cellular uptake and cytotoxicity of anthracyclines decrease with increasing cell density in vitro, an event termed 'the inocculum effect'. It is not known whether such an effect occurs in vivo. In this study the relationships between white blood cell (WBC) count, plasma and cellular concentrations of daunorubicin (DNR) in patients with acute myeloid leukaemia were investigated. METHODS Plasma and mononuclear blood cells were isolated from peripheral blood from 40 patients with acute myeloid leukaemia at end of infusion (time 1 h), 5 and 24 h following the first DNR infusion. DNR concentrations were determined by high-pressure liquid chromatography and related to the WBC count at diagnosis. A population pharmacokinetic model was used to estimate the correlations between baseline WBC count, volume of distribution and clearance of DNR. RESULTS A clear but weak inverse relationship between the baseline WBC count and plasma concentrations of DNR (r2 = 0.11, P < 0.05) at time 1 was found. Furthermore, a clear relationship between baseline WBC count and DNR central volume of distribution using population pharmacokinetic modelling (dOFV 4.77, P < 0.05) was also noted. Analysis of plasma DNR and the metabolite daunorubicinol (DOL) concentrations in patients with a high WBC count support that the low DNR/DOL concentrations are due a distribution effect. CONCLUSION This study shows that the leukaemic cell burden influences the plasma concentrations of anthracyclines. Further studies are needed to explore if patients with high a WBC count may require higher doses of anthracyclines.
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- Ma, Guangli, et al.
(författare)
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Comparison of the agonist-antagonist interaction model and the pool model for the effect of remoxipride on prolactin
- 2010
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Ingår i: British Journal of Clinical Pharmacology. - : Wiley. - 0306-5251 .- 1365-2125. ; 70:6, s. 815-824
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Tidskriftsartikel (refereegranskat)abstract
- AIMS The tolerance to the prolactin response following administration of antipsychotic drugs has been modelled as a depletion of a prolactin pool (pool model) and a model where the tolerance is explained by a feedback loop including the dopamine interaction of prolactin release (agonist-antagonist interaction model, (AAI model)). The AAI model was superior to the pool model when analyzing data from clinical trials of risperidone and paliperidone. Here we evaluated the two models using the remoxipride data, designed to challenge the short-term prolactin response, from which the original pool model was built. METHODS The remoxipride data were collected from a study where eight healthy male subjects received two remoxipride infusions on five occasions. The intervals between the first and second dose on each occasion were 2, 8, 12, 24 and 48 h, respectively. The pool and AAI models were fitted using NONMEM. RESULTS According to the objective function values the pool model with a circadian rhythm function fitted the data slightly better, while the AAI model was better in describing the circadian rhythm of prolactin. Visual predictive checks revealed that the models predicted the prolactin profiles equally well. CONCLUSIONS According to the analysis performed here, a previous analysis of several clinical studies and literature reports on prolactin concentrations, it appears that the dopamine feedback mechanism included in the AAI model is better than the storage depletion mechanism in the pool model to estimate the bio-rhythm of prolactin time-course and the tolerance development across different populations, drugs, treatment schedules and time.
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