Thromboembolic Events in Users of Warfarin Treated with Different Skeletal Muscle Relaxants.
Medicina (Kaunas)
; 58(9)2022 Aug 29.
Article
em En
| MEDLINE
| ID: mdl-36143848
ABSTRACT
Background and Objectives:
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. Materials andMethods:
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.Results:
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.Conclusions:
We identified a potential >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.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tromboembolia
/
Fármacos Neuromusculares
Tipo de estudo:
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Humans
Idioma:
En
Revista:
Medicina (Kaunas)
Assunto da revista:
MEDICINA
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Estados Unidos