Search results for "Drug Interaction"
showing 10 items of 246 documents
Comparison of different methods: static and dynamic headspace and solid-phase microextraction for the measurement of interactions between milk protei…
2002
Interactions between 10 aroma compounds from different chemical classes and 5 mixtures of milk proteins have been studied using static or dynamic headspace gas chromatography and solid-phase microextraction (SPME). Static headspace analysis allows the quantification of the release of only the most abundant compounds. Dynamic headspace analysis does not allow the discrimination of flavor release from the different protein mixtures, probably due to a displacement of headspace equilibrium. By SPME analysis and quantification by GC-MS (SIM mode) all of the volatiles were quantified. This method was optimized to better discriminate aroma release from the different milk protein mixtures and then …
Anti-Hypotensive Treatment and Endothelin Blockade Synergistically Antagonize Exercise Fatigue in Rats under Simulated High Altitude
2013
Rapid ascent to high altitude causes illness and fatigue, and there is a demand for effective acute treatments to alleviate such effects. We hypothesized that increased oxygen delivery to the tissue using a combination of a hypertensive agent and an endothelin receptor A antagonist drugs would limit exercise-induced fatigue at simulated high altitude. Our data showed that the combination of 0.1 mg/kg ambrisentan with either 20 mg/kg ephedrine or 10 mg/kg methylphenidate significantly improved exercise duration in rats at simulated altitude of 4,267 m, whereas the individual compounds did not. In normoxic, anesthetized rats, ephedrine alone and in combination with ambrisentan increased heart…
The relaxant effects of cromakalim (BRL 34915) on human isolated airway smooth muscle
1992
Cromakalim (BRL 34915) is a potassium channel opener with therapeutic potential as a bronchodilator in asthma. Cromakalim (0.1–30 μmol/l) inhibited the spontaneous tone of human isolated bronchi n a concentration-related manner being nearly as effective as isoprenaline or theophylline. The order of relaxant potencies (expressed as -log10 IC50 mol/l; mean ±SEM) was isoprenaline (7.29 ± 0.27; n = 8) > cromakalim (5.89 ± 0.12; n = 7) > theophylline (4.07 ±0.13; n = 10). In human bronchi where tone had been raised by addition of histamine (0.1 mmol/l), acetylcholine (0.1 mmol/l) or leukotriene D4 (LTD4, 0.1 μmol/l), the relaxant effect of cromakalim was substantially reduced. Cromakalim suppres…
Pharmacokinetic interaction between efavirenz and ketoconazole in rats
2009
It is well known that efavirenz and ketoconazole act as an inducer and inhibitor of CYP3A4, respectively. As a result of these actions, co-administration of these drugs may result in changes in the pharmacoki- netic parameters of one or both of them. 2. Duodenum-cannulated rats have been used to compare the effect of intraduodenal (KC i.d. ) and intrave- nous administration of ketoconazole (KC i.v. ) on the pharmacokinetics of efavirenz after intraduodenal administration, as well as the potential effect of efavirenz as a CYP450 inducer on ketoconazole phar - macokinetic profile. 3. While KC i.v. did not show any significant effect on efavirenz pharmacokinetic profile, KC i.d. increased sig-…
Inhibition of Efavirenz Metabolism by Sertraline and Nortriptyline and Their Effect on Efavirenz Plasma Concentrations.
2015
ABSTRACT Between 22 and 45% of HIV-positive subjects are likely to report symptoms of depression. Considering this background, a potential pharmacokinetic interaction between the nonnucleoside reverse transcriptase inhibitor efavirenz (EFV) and two antidepressants, sertraline (SRT) and nortriptyline (NT), was studied. Rats were administered EFV alone or together with the antidepressants, and changes in the plasma levels and pharmacokinetic parameters of EFV were analyzed. Additional in vitro experiments with rat and human hepatic microsomes were carried out to evaluate the inhibitory effect of SRT and NT on EFV metabolism by determining the formation rate of the major EFV metabolite (8-OH-E…
[Pharmacological treatment of depression after acute myocardial infarction].
2005
Depressed mood and other depressive symptoms frequently appear after acute myocardial infarction and it is known how these patients have an increased risk for morbidity and mortality compared to patients without depression. Many risk factors promote the development of clinical depression in patients with recent myocardial infarction. Although a large number of studies underline the negative prognostic impact of depression on the infarcted patient, only rarely depressed patients are appropriately diagnosed and treated. Furthermore it should be borne in mind that the use of psychotropics in medically ill patients requires attention. These compounds, in fact, may interact with the disease caus…
Metal ions modify DNA-protecting and mutagen-scavenging capacities of the AV-153 1,4-dihydropyridine.
2019
Abstract 1,4-Dihydropyridines (1,4-DHP) possess important biochemical and pharmacological properties, including antioxidant and antimutagenic activities. AV-153-Na, an antimutagenic and DNA-repair enhancing compound was shown to interact with DNA by intercalation. Here we studied DNA binding of several AV-153 salts to evaluate the impact of AV-153 modifications on its DNA binding capacity, the ability to scavenge the peroxynitrite, to protect HeLa and B-cells cells against DNA damage. Affinity of the AV-153 salts to DNA measured by a fluorescence assay was dependent on the metal ion forming a salt in position 4 of the 1,4-DHP, and it decreased as follows: Mg > Na > Ca > Li > Rb > K. AV-153-…
Glycoconjugate vaccines and immune interactions, and implications for vaccination schedules.
2011
Conjugate vaccines using diphtheria toxoid variant (CRM(197)), diphtheria toxoid and tetanus toxoid (TT) as carrier protein may induce immune interactions (interference or impairment as measured by lower antibody levels, or enhancement [higher antibody levels]) when coadministered with other vaccines. Immune enhancement occurs when two TT conjugates are coadministered. CRM(197) conjugate vaccines induce immune bystander interference when given with diphtheria-tetanus-acellular pertussis vaccines, which reduces responses to coadministered Haemophilus influenzae type b vaccine conjugated to TT. These bystander effects are greater as the amount of CRM(197) administered increases. When large am…
Intestinal drug efflux: formulation and food effects
2001
The intestine, primarily regarded as an absorptive organ, is also prepared for the elimination of certain organic acids, bases and neutral compounds depending on their affinity to intestinal carrier systems. Several of the transport systems known to mediate efflux in the major clearing organs--liver and kidney--are also expressed in the intestine. Examples of secretory transporters in the intestine are P-glycoprotein, members of the multidrug resistance associated protein family, breast cancer resistance protein, organic cation transporters and members of the organic anion polypeptide family. In this communication, the P-glycoprotein mediated intestinal secretion of talinolol, a model compo…
The Influence of Single-Dose and Short-Term Administration of Quercetin on the Pharmacokinetics of Midazolam in Humans.
2015
Quercetin is a plant flavonol that is available from both daily diet and nutraceuticals. To investigate the effect of acute and short-term intake of high-dose quercetin on CYP3A-mediated metabolism, 10 healthy volunteers received 7.5 mg oral midazolam without, with a single dose of 1500 mg quercetin and after 1-week supplementation with 1500 mg quercetin daily. A substudy was performed in three subjects to explore the impact of repeated quercetin intake on intravenously administered midazolam. Coadministration with a single dose of quercetin did not significantly alter the pharmacokinetics of midazolam and its 1'-hydroxymetabolite, but following short-term quercetin intake, there was a tren…