MAJOR — Use With Caution
FDA-documented interaction. Fluvoxamine is the SSRI most likely to increase warfarin levels (strong CYP1A2 + moderate CYP2C9 inhibition). INR monitoring essential.
Evidence level: STRONG
Fluvoxamine (Luvox) can significantly increase warfarin blood levels by blocking the enzymes that break warfarin down. Additionally, all SSRIs thin the blood slightly on their own by affecting platelet function.
Fluvoxamine is a potent CYP1A2 inhibitor and moderate CYP2C9 inhibitor. Warfarin R-enantiomer is metabolized by CYP1A2, S-enantiomer by CYP2C9. Fluvoxamine significantly increases warfarin levels. FDA warfarin label lists SSRIs. All SSRIs also increase bleeding risk via serotonin-mediated platelet effects.
If you take warfarin and need an antidepressant, fluvoxamine is one of the riskiest choices. Get INR checked within a week of starting, and discuss whether a different antidepressant would be safer.
SSRIs impair platelet function, which can amplify anticoagulant effects and increase bleeding risk. Take each at their normal prescribed times. Your prescriber should monitor for signs of bleeding (bruising, dark stools, prolonged cuts). INR monitoring may be more frequent if on warfarin.
Higher risk for: elderly patients, those with liver disease, history of GI bleeding, concurrent use of multiple blood thinners, recent surgery, vitamin K intake changes, alcohol use, or low body weight.
Easy bruising, nosebleeds, blood in urine or stool, bleeding gums, prolonged bleeding from cuts
Monitor INR closely. Consider alternative SSRIs with less CYP inhibition (sertraline, citalopram). Remember all SSRIs carry some bleeding risk via platelet effects.
Discuss this combination with your prescriber. They may adjust timing, dosing, or switch to an alternative with fewer interaction risks. Never stop an antidepressant abruptly — taper under medical guidance.
Fluvoxamine (Luvox) can significantly increase warfarin blood levels by blocking the enzymes that break warfarin down. Additionally, all SSRIs thin the blood slightly on their own by affecting platelet function.
SSRIs impair platelet function, which can amplify anticoagulant effects and increase bleeding risk. Take each at their normal prescribed times. Your prescriber should monitor for signs of bleeding (bruising, dark stools, prolonged cuts). INR monitoring may be more frequent if on warfarin.
Easy bruising, nosebleeds, blood in urine or stool, bleeding gums, prolonged bleeding from cuts
Discuss this combination with your prescriber. They may adjust timing, dosing, or switch to an alternative with fewer interaction risks. Never stop an antidepressant abruptly — taper under medical guidance.
Monitor INR closely. Consider alternative SSRIs with less CYP inhibition (sertraline, citalopram). Remember all SSRIs carry some bleeding risk via platelet effects.
Or browse the full interaction database (121,000+ pairs).