title: The effect of converting from pravastatin to simvastatin on the pharmacodynamics of warfarin.
abstract: Forty-six adult patients maintained on warfarin therapy were converted from pravastatin to simvastatin. Mean international normalized ratio (INR) significantly increased from 2.42 to 2.74, p = 0.002. Although warfarin doses were reduced in 7 patients and increased in 4 patients following the post-conversion INR measurements, the pre- and postconversion median weekly warfarin dose of all 46 patients did not differ significantly. The number of patients with an INR > 3.0 increased significantly from 6 to 16 following the conversion. There was no report of unusual episodes of bleeding. The results indicate that antihyperlipidemic therapy can be changed safely from pravastatin to simvastatin in patients who are taking warfarin concomitantly. Additional anticoagulation monitoring is not necessary in institutions where patients are followed in formal anticoagulation clinics.
authors.affiliation: Cardiovascular Pharmacodynamics Laboratory, Veterans Administration Healthcare System, San Diego, California, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Lin
authors.forename: M K
authors.initials: MK
authors.lastname: Ito
authors.forename: S N
authors.initials: SN
authors.lastname: Stolley
authors.forename: A P
authors.initials: AP
authors.lastname: Morreale
authors.forename: D B
authors.initials: DB
authors.lastname: Marcus
mesh_terms: D000368:Aged; D000924:Anticholesteremic Agents / Q000494:pharmacology*; D000925:Anticoagulants / Q000494:pharmacology*; D002986:Clinical Trials as Topic; D015331:Cohort Studies; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005260:Female; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D017035:Pravastatin / Q000494:pharmacology*; D012189:Retrospective Studies; D019821:Simvastatin / Q000494:pharmacology*; D013997:Time Factors; D014859:Warfarin / Q000494:pharmacology*