<p>Increased risk of serotonin syndrome with TCA, SSRI, SNRI, lithium, sibutramine, tramadol. May increase serum levels with CYP3A4 inhibitors (e.g. ketoconazole, atazanavir, clarithromycin). May increase serum levels of haloperidol. May decrease serum levels of indinavir. May increase bleeding risk with aspirin, NSAIDs, warfarin and other anticoagulants.</p>