Tramadol-warfarin interaction.
A 61-year-old women receiving warfarin after mitral valve replacement experienced extensive ecchymoses after starting tramadol therapy. Laboratory values revealed critical elevations of prothrombin time and international normalized ratio. The patient's coagulation values returned to acceptable levels after discontinuing tramadol and temporarily stopping warfarin. The mechanism for this interaction is unknown. Practitioners should be aware of the possibility of such a interaction and exercise caution when tramadol is prescribed for a patient receiving warfarin.
Samford University McWhorter School of Pharmacy, Department of Pharmacy Practice, Birmingham, Alabama, USA.
J R
JR
Sabbe
P J
PJ
Sims
M H
MH
Sims
D000701:Analgesics, Opioid / Q000009:adverse effects* / Q000627:therapeutic use; D000925:Anticoagulants / Q000009:adverse effects* / Q000627:therapeutic use; D004347:Drug Interactions; D004438:Ecchymosis / Q000139:chemically induced; D005260:Female; D006801:Humans; D008875:Middle Aged; D014147:Tramadol / Q000009:adverse effects* / Q000627:therapeutic use; D014859:Warfarin / Q000009:adverse effects* / Q000627:therapeutic use
D000701:Analgesics, Opioid; D000925:Anticoagulants; D014147:Tramadol; D014859:Warfarin