{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"submitter":["Leonard CE"],"funding":["NIA NIH HHS","NIDA NIH HHS","NIGMS NIH HHS"],"pagination":["1171"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC9501796"],"repository":["biostudies-literature"],"omics_type":["Unknown"],"volume":["58(9)"],"pubmed_abstract":["<i>Background and Objectives</i>: Warfarin and a skeletal muscle relaxant are co-treatments in nearly a quarter-million annual United States (US) office visits. Despite international calls to minimize patient harm arising from anticoagulant drug interactions, scant data exist on clinical outcomes in real-world populations. We examined effects of concomitant use of warfarin and individual muscle relaxants on rates of hospitalization for thromboembolism among economically disadvantaged persons. <i>Materials and Methods</i>: Using 1999-2012 administrative data of four US state Medicaid programs, we conducted 16 retrospective self-controlled case series studies: half included concomitant users of warfarin + one of eight muscle relaxants; half included concomitant users of an inhaled corticosteroid (ICS) + one of eight muscle relaxants. The ICS analyses served as negative control comparisons. In each study, we calculated incidence rate ratios (IRRs) comparing thromboembolism rates in the co-exposed versus warfarin/ICS-only exposed person-time, adjusting for time-varying confounders. <i>Results</i>: Among ~70 million persons, we identified 8693 warfarin-treated subjects who concomitantly used a muscle relaxant, were hospitalized for thromboembolism, and met all other inclusion criteria. Time-varying confounder-adjusted IRRs ranged from 0.31 (95% confidence interval: 0.13-0.77) for metaxalone to 3.44 (95% confidence interval: 1.53-7.78) for tizanidine. The tizanidine finding was robust after quantitatively adjusting for negative control ICS findings, and in numerous prespecified secondary analyses. <i>Conclusions</i>: We identified a potential &gt;3-fold increase in the rate of hospitalized thromboembolism in concomitant users of warfarin + tizanidine vs. warfarin alone. Alternative explanations for this finding include confounding by indication, a native effect of tizanidine, or chance."],"journal":["Medicina (Kaunas, Lithuania)"],"pubmed_title":["Thromboembolic Events in Users of Warfarin Treated with Different Skeletal Muscle Relaxants."],"pmcid":["PMC9501796"],"funding_grant_id":["R01 AG025152","R01 AG060975","T32GM075766","T32 GM075766","R01AG025152; R01AG060975; R01AG064589","R01DA048001","R01 DA048001","R01 AG064589"],"pubmed_authors":["Hecht TEH","Soprano SE","Ashcroft DM","Bilker WB","Dhopeshwarkar N","Nutescu EA","Carr M","Brensinger CM","Chen C","Leonard CE","Kasner SE","Holbrook A","Hennessy S"],"additional_accession":[]},"is_claimable":false,"name":"Thromboembolic Events in Users of Warfarin Treated with Different Skeletal Muscle Relaxants.","description":"<i>Background and Objectives</i>: Warfarin and a skeletal muscle relaxant are co-treatments in nearly a quarter-million annual United States (US) office visits. Despite international calls to minimize patient harm arising from anticoagulant drug interactions, scant data exist on clinical outcomes in real-world populations. We examined effects of concomitant use of warfarin and individual muscle relaxants on rates of hospitalization for thromboembolism among economically disadvantaged persons. <i>Materials and Methods</i>: Using 1999-2012 administrative data of four US state Medicaid programs, we conducted 16 retrospective self-controlled case series studies: half included concomitant users of warfarin + one of eight muscle relaxants; half included concomitant users of an inhaled corticosteroid (ICS) + one of eight muscle relaxants. The ICS analyses served as negative control comparisons. In each study, we calculated incidence rate ratios (IRRs) comparing thromboembolism rates in the co-exposed versus warfarin/ICS-only exposed person-time, adjusting for time-varying confounders. <i>Results</i>: Among ~70 million persons, we identified 8693 warfarin-treated subjects who concomitantly used a muscle relaxant, were hospitalized for thromboembolism, and met all other inclusion criteria. Time-varying confounder-adjusted IRRs ranged from 0.31 (95% confidence interval: 0.13-0.77) for metaxalone to 3.44 (95% confidence interval: 1.53-7.78) for tizanidine. The tizanidine finding was robust after quantitatively adjusting for negative control ICS findings, and in numerous prespecified secondary analyses. <i>Conclusions</i>: We identified a potential &gt;3-fold increase in the rate of hospitalized thromboembolism in concomitant users of warfarin + tizanidine vs. warfarin alone. Alternative explanations for this finding include confounding by indication, a native effect of tizanidine, or chance.","dates":{"release":"2022-01-01T00:00:00Z","publication":"2022 Aug","modification":"2025-04-18T22:29:01.666Z","creation":"2024-10-19T08:20:53.586Z"},"accession":"S-EPMC9501796","cross_references":{"pubmed":["36143848"],"doi":["10.3390/medicina58091171"]}}