Trial reportBritish journal of clinical pharmacology2014
Urinary coproporphyrin I/(I + III) ratio as a surrogate for MRP2 or other transporter activities involved in methotrexate clearance.
Trial report in British journal of clinical pharmacology, 2014. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 7 papers, 1 of them a synthesis that pooled it.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
7 citing papers in PubMed, 1 synthesis or guideline pooled it, 20 citations in OpenAlex.
- Factors influencing methotrexate pharmacokinetics highlight the need for individualized dose adjustment: a systematic review.European journal of clinical pharmacology · 2024Pooled it
- Coproporphyrin I as an in vitro fluorescent probe to measure OATP1B1 transport activity.Drug metabolism and disposition: the biological fate of chemicals · 2025Article
- Population Pharmacokinetic and Toxicity Analysis of High-Dose Methotrexate in Patients with Central Nervous System Lymphoma.Clinical pharmacokinetics · 2025Article
- Progress of coproporphyrin as an endogenous biomarker for transporter-mediated drug-drug interactions.Frontiers in pharmacology · 2025Review
- Increased coproporphyrin serum levels in healthy volunteers treated with the cholesterol uptake inhibitor ezetimibe.Clinical and translational science · 2024Article
- Evaluation and Application of Population Pharmacokinetic Models for Identifying Delayed Methotrexate Elimination in Patients With Primary Central Nervous System Lymphoma.Frontiers in pharmacology · 2022Article
- In Vitro Stimulation of Multidrug Resistance-Associated Protein 2 Function Is Not Reproduced In Vivo in Rats.Pharmaceutics · 2018Article
Corrections and comments
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Authors and funding
10 authors at 4 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
aimsThe urinary coproporphyrin I/(I + III) ratio may be a surrogate for MRP2 activity. We conducted a prospective study in patients receiving methotrexate (MTX) to examine the relationship between this ratio and the pharmacokinetics of a MRP2 substrate.
methodsThree urine samples were collected from 81 patients for UCP I/(I + III) ratio determination: one before (P1), one at the end of MTX infusion (P2), and one on the day of hospital discharge (P3). Three polymorphisms of ABCC2 were analysed and their relationships with basal UCP I/(I + III) ratio values assessed. All associated drugs were recorded and a drug interaction score (DIS) was assigned. Population pharmacokinetic analysis was conducted to assess whether MTX clearance (MTXCL) was associated with the basal UCP I/(I + III) ratio, its variation during MTX infusion, the DIS or other common covariates.
resultsThe basal UCP I/(I + III) ratio was not associated with ABCC2 polymorphisms and did not differ according to the DIS. Significant changes in the ratio were observed over time, with an increase between P1 and P2 and a decrease at P3 (P < 0.001). No association was found between basal UCP I/(I + III) ratio and MTXCL. The final model indicates that MTXCL was dependent on the change in the ratio between P1 and P3, DIS and creatinine clearance.
conclusionThe basal UCP I/(I + III) ratio is not predictive of MTXCL. However, it is sensitive to the presence of MTX, so it is plausible that it reflects a function modified in response to the drug.
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