title: Investigating unexpected INRs: in search of the culprit--adherence, interactions, genetics, and superwarfarin.
abstract: Treatment with coumarin derivatives is highly individualised due to high intra- and inter-individual variation in dose response and risks of severe bleeding or thromboembolic complications. Treatment focuses on reaching and maintaining a stable target international normalised ratio (INR). However, unexpected INRs that are not explained by noncompliance or vitamin K intake may occur. Here we describe seven cases of unexpected INRs, and provide clues that clarify the underlying mechanism.
authors.affiliation: Laboratory of Molecular Diagnostics, Jeroen Bosch Hospital, 's-Hertogenbosch, the Netherlands.
authors.forename: P C J
authors.initials: PC
authors.lastname: Schmeits
authors.forename: N C V
authors.initials: NC
authors.lastname: Péquériaux
authors.forename: J H H
authors.initials: JH
authors.lastname: van Geest-Daalderop
authors.forename: M E
authors.initials: ME
authors.lastname: Ouwehand
authors.forename: A M J
authors.initials: AM
authors.lastname: Coremans
authors.forename: M H A
authors.initials: MH
authors.lastname: Hermans
authors.forename: J M H
authors.initials: JM
authors.lastname: Conemans
mesh_terms: D015110:4-Hydroxycoumarins; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics; D003374:Coumarins; D065729:Cytochrome P-450 CYP2C9; D004347:Drug Interactions; D005260:Female; D014644:Genetic Variation; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D006899:Mixed Function Oxygenases / Q000235:genetics; D012307:Risk Factors; D064417:Vitamin K Epoxide Reductases; D055815:Young Adult
chemical_list: D015110:4-Hydroxycoumarins; D000925:Anticoagulants; D003374:Coumarins; C013418:bromfenacoum; C030123:coumarin; D006899:Mixed Function Oxygenases; C450260:CYP2C9 protein, human; D065729:Cytochrome P-450 CYP2C9; D001189:Aryl Hydrocarbon Hydroxylases; D064417:Vitamin K Epoxide Reductases