The influence of a single and chronic administration of venlafaxine on tramadol pharmacokinetics in a rabbit model

Crizotinib inhibits the metabolism of tramadol by non-competitive suppressing the activities of CYP2D1 and CYP3A2

Objectives

To investigate the interaction between tramadol and representative tyrosine kinase inhibitors, and to study the inhibition mode of drug-interaction.

Methods

Liver microsomal catalyzing assay was developed. Sprague-Dawley rats were administrated tramadol with or without selected tyrosine kinase inhibitors. Samples were prepared and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used for analysis. Besides, liver, kidney, and small intestine were collected and morphology was examined by hematoxyline-eosin (H&E) staining. Meanwhile, liver microsomes were prepared and carbon monoxide differential ultraviolet radiation (UV) spectrophotometric quantification was performed.

Results

Among the screened inhibitors, crizotinib takes the highest potency in suppressing the metabolism of tramadol in rat/human liver microsome, following non-competitive inhibitory mechanism. In vivo, when crizotinib was co-administered, the AUC value of tramadol increased compared with the control group. Besides, no obvious pathological changes were observed, including cell morphology, size, arrangement, nuclear morphology with the levels of alanine transaminase (ALT) and aspartate transaminase (AST) increased after multiple administration of crizotinib. Meanwhile, the activities of CYP2D1 and CYP3A2 as well as the total cytochrome P450 abundance were found to be decreased in rat liver of combinational group.

Conclusions

Crizotinib can inhibit the metabolism of tramadol. Therefore, this recipe should be vigilant to prevent adverse reactions.

Removal of tramadol from water using Typha angustifolia and Hordeum vulgare as biological models: Possible interaction with other pollutants in short-term uptake experiments

Tramadol (TRD) is widely detected in aquatic ecosystems as a result of massive abuse and insufficient removal from wastewater facilities. As a result, TRD can contaminate groundwater sources and/or agricultural soils. While TRD toxicity has been reported from aquatic biota, data about TRD detection in plants are scarce. Moreover, information regarding plant capability for TRD removal is lacking. To understand the fate of this opioid, we have investigated the uptake, translocation and removal capacity of TRD by plants, addressing short-term and long-term uptake. The uptake rates of TRD, in excised barley and cattail roots, were 5.18 and 5.79 μg g^-1 root fresh weight day^-1, respectively. However, TRD uptake was strongly inhibited after co-exposing these roots either with the drug venlafaxine (similar molecular structure as TRD) or with quinidine (an inhibitor of cellular organic cation transporters). When barley seedlings were exposed to TRD in a hydroponic experiment a removal efficiency up to 90% (within 15 days) was obtained, with bioconcentration and translocation factors close to 9 and 1, respectively. The combination of results from both plants and the inhibition observed after treatment with quinidine revealed that organic cation transporters may be involved in the uptake of TRD by plants.