Investigating unexpected INRs: in search of the culprit--adherence, interactions, genetics, and superwarfarin.
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.
Schmeits
P C J
PC
Laboratory of Molecular Diagnostics, Jeroen Bosch Hospital, 's-Hertogenbosch, the Netherlands.
Péquériaux
N C V
NC
van Geest-Daalderop
J H H
JH
Ouwehand
M E
ME
Coremans
A M J
AM
Hermans
M H A
MH
Conemans
J M H
JM
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
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