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Drug‐drug interaction between warfarin and statins: A Danish cohort study
Author(s) -
Engell Anna E.,
Svendsen Andreas L.O.,
Lind Bent S.,
Andersen Christen L.,
Andersen John S.,
Willadsen Tora G.,
Persson Frederik,
Pottegård Anton
Publication year - 2021
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1111/bcp.14428
Subject(s) - rosuvastatin , warfarin , atorvastatin , simvastatin , medicine , statin , drug interaction , drug , cohort , pharmacology , atrial fibrillation
Initiation of statin treatment is suggested to increase the international normalised ratio (INR) among warfarin users. However, available data is limited and conflicting. We conducted a register‐based cohort study to evaluate the drug‐drug interaction between warfarin and statins. By linking data on INR measurements and filled prescriptions, we identified warfarin users 2000‐2015 initiating simvastatin (n = 1363), atorvastatin (n = 165) or rosuvastatin (n = 23). Simvastatin initiation led to an increase in mean INR from 2.40 to 2.71, with INRs peaking after 4 weeks, corresponding to a mean change of 0.32 (95%CI 0.25‐0.38). High‐dose and low‐dose simvastatin led to comparable changes (mean change 0.33 vs 0.29). Initiation of atorvastatin and rosuvastatin lead to INR increases of 0.27 (95%CI 0.12‐0.42) and 0.30 (95%CI ‐0.09‐0.69). In conclusion, initiation of simvastatin, atorvastatin or rosuvastatin among warfarin users led to a minor increase in INR. The magnitude of this change is for most patients likely of limited clinical relevance.