A 63-year-old man was recently placed on warfarin (Coumadin) by his nurse practitioner. Which of the following supplements will he need to discontinue?

Choice A reason: SAM-e (S-adenosylmethionine) can increase the risk of bleeding by enhancing anticoagulant effects when combined with warfarin. Patients on warfarin must avoid SAM-e due to the potential for potentiating anticoagulation and increasing the risk of hemorrhage. Choice B reason: Omega-3 fatty acids may have mild antiplatelet effects but generally do not significantly interact with warfarin at typical dietary doses. Clinicians monitor coagulation parameters but do not universally require discontinuation. Choice C reason: Melatonin is primarily used for sleep regulation and has minimal effect on warfarin metabolism. It does not pose a significant bleeding risk. Choice D reason: Tryptophan is a precursor to serotonin and primarily affects mood and sleep. It has no clinically significant effect on warfarin or coagulation.