Effects of tramadol coadministration on prothrombin time-international normalized ratio in patients receiving warfarin

0Citations
Citations of this article
20Readers
Mendeley users who have this article in their library.

Abstract

Several case studies have reported a possible drug interaction between warfarin and tramadol where tramadol coadministration enhanced the antithrombotic effects of warfarin. To assess this drug interaction, changes in prothrombin time-international normalized ratio (PT-INR) before and after tramadol coadministration were investigated in patients receiving warfarin. For this study, we examined 54 patients (male/female: 22/32, 68.4±12.7 years) who were being treated with warfarin for deep vein thrombosis, atrial fibrillation, arteriosclerosis obliterans, congestive heart failure, and other vascular diseases. Significant increases in PT-INR were observed 9.5 (1-118) d after coadministration of tramadol (1.81±0.56 vs. 2.47±1.10, p<0.01). Twenty-eight patients (PT-INR increased group) with PT-INR elevation of greater than 0.5 or dose reduction of warfarin after coadministration of tramadol were compared with other groups of patients to find drug interaction risk factors. Logistic regression analysis revealed that lower levels of albumin (3.5 g/dL or less) [odds ratio (OR) 22.1; 95%CI 2.9-169.9]; lower eGFR (50 mL/min or less) (OR 7.7; 95%CI 1.4-42.0); and PT-INR before tramadol coadministration (OR 38.2; 95%CI 3.7-397.6) were characteristic of the PT-INR increased group. These results suggest that tramadol coadministration enhanced the antithrombotic effects of warfarin in patients with higher PT-INR, lower albumin levels and decreased renal function as the risk factors for this drug interaction.

Cite

CITATION STYLE

APA

Hosono, T., Kondo, A., Kambayashi, Y., & Homma, M. (2017). Effects of tramadol coadministration on prothrombin time-international normalized ratio in patients receiving warfarin. Yakugaku Zasshi. Pharmaceutical Society of Japan. https://doi.org/10.1248/yakushi.16-00270

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free