OBJECTIVE: To determine the influence of NSAIDs on the international normalized ratio (INR) in patients with cytochrome P450 (CYP)-2C9 enzyme variants starting acenocoumarol (an oral coumarin) therapy during the first 7 days after total hip replacement surgery. METHODS: In this prospective study, an age-dependent protocol was used for the initiation of the acenocoumarol dose. Low-molecular-weight heparin was given for 5 days. The study included 100 patients undergoing total hip replacement surgery. After the inclusion of the last patient, polymerase chain reaction CYP2C9 mutation testing was performed for all patients. Drug-use evaluation of NSAIDs and other potential coumarin-drug interactions was also performed. RESULTS: Eleven patients had an INR on 1 or more days >4.9. There were 52 patients who were using NSAIDs. Patients with a CYP2C9 mutation had a mean INR curve similar to patients without the mutation when NSAIDs were not coadministered. Within the group of patients heterozygous for a CYP2C9 mutation (n=30) only concomitant use of a NSAID resulted in an INR >4.9 (0% vs 38.9%, p<0.05). CONCLUSION: In the group of patients with a CYP2C9 variant (*2 or *3 alleles), only concomitant use of a NSAID resulted in INRs >4.9. The cost effectiveness of CYP2C9 screening before elective surgery has yet to be determined.
OBJECTIVE: To determine the influence of NSAIDs on the international normalized ratio (INR) in patients with cytochrome P450 (CYP)-2C9 enzyme variants starting acenocoumarol (an oral coumarin) therapy during the first 7 days after total hip replacement surgery. METHODS: In this prospective study, an age-dependent protocol was used for the initiation of the acenocoumarol dose. Low-molecular-weight heparin was given for 5 days. The study included 100 patients undergoing total hip replacement surgery. After the inclusion of the last patient, polymerase chain reaction CYP2C9 mutation testing was performed for all patients. Drug-use evaluation of NSAIDs and other potential coumarin-drug interactions was also performed. RESULTS: Eleven patients had an INR on 1 or more days >4.9. There were 52 patients who were using NSAIDs. Patients with a CYP2C9 mutation had a mean INR curve similar to patients without the mutation when NSAIDs were not coadministered. Within the group of patients heterozygous for a CYP2C9 mutation (n=30) only concomitant use of a NSAID resulted in an INR >4.9 (0% vs 38.9%, p<0.05). CONCLUSION: In the group of patients with a CYP2C9 variant (*2 or *3 alleles), only concomitant use of a NSAID resulted in INRs >4.9. The cost effectiveness of CYP2C9 screening before elective surgery has yet to be determined.
Authors: Loes E Visser; Ron H N van Schaik; Martin van Vliet; Paul H Trienekens; Peter A G M De Smet; Arnold G Vulto; Albert Hofman; Cornelia M van Duijn; Bruno H Ch Stricker Journal: Clin Pharmacol Ther Date: 2005-06 Impact factor: 6.875
Authors: Mitchell K Higashi; David L Veenstra; L Midori Kondo; Ann K Wittkowsky; Sengkeo L Srinouanprachanh; Fred M Farin; Allan E Rettie Journal: JAMA Date: 2002-04-03 Impact factor: 56.272
Authors: M Margaglione; D Colaizzo; G D'Andrea; V Brancaccio; A Ciampa; E Grandone; G Di Minno Journal: Thromb Haemost Date: 2000-11 Impact factor: 5.249
Authors: Karen N van Dijk; Arian W Plat; Alieke A C van Dijk; Margriet Piersma-Wichers; Anne M B de Vries-Bots; Jennita Slomp; Lolkje T W de Jong-van den Berg; Jacobus R B J Brouwers Journal: Thromb Haemost Date: 2004-01 Impact factor: 5.249