AIM The aim of this study was to investigate the effects of co-medication with selective serotonin re-uptake inhibitors (SSRIs) on overanticoagulation during acenocoumarol maintenance treatment. METHODS All subjects from The Rotterdam Study who received acenocoumarol maintenance treatment between April 1 1991 and September 9 2009 were followed for the event of an international normalized ratio (INR) ≥6, until death, end of treatment or end of the study period. With the Andersen-Gill extension of the Cox proportional hazards model, risks for repeated events of overanticoagulation in relation to concomitant SSRI use were calculated. RESULTS The risk for overanticoagulation during acenocoumarol maintenance treatment was increased in combination with fluvoxamine (HR 2.63, 95% CI 1.49, 4.66) and venlafaxine (HR 2.19, 95% CI 1.21, 3.99). There was no increase in risk for the other SSRIs, but numbers of exposed cases were low for all SSRIs except paroxetine. CONCLUSION Fluvoxamine and venlafaxine were associated with a more than double risk of INR values ≥6 in acenocoumarol treated subjects. © 2011 The Authors. British Journal of Clinical Pharmacology

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British Journal of Clinical Pharmacology
Erasmus MC: University Medical Center Rotterdam

Teichert, M., Visser, L., Uitterlinden, A., Hofman, A., Buhre, P., Straus, S., … Stricker, B. (2011). Selective serotonin re-uptake inhibiting antidepressants and the risk of overanticoagulation during acenocoumarol maintenance treatment. British Journal of Clinical Pharmacology, 72(5), 798–805. doi:10.1111/j.1365-2125.2011.04004.x