Antidepressant Medications and Warfarin

Publication Date: 
Sat, 11/01/2014
By: Alere Staff

Antidepressant Medications and Warfarin

Sometimes life can get overwhelming; medications to support our emotions are prescribed to assist us while we go through the trials of life. You may be wary to take these medications because of potential side effects. There are many different medications to choose from and, if taken properly, these medications can help. However if you are taking warfarin (or brand of warfarin such as Coumadin®), it is important to remember that some of antidepressant might interact with your warfarin, requiring your warfarin to be monitored closely.


Your doctor will help you with questions on which medication is right for you and how often you will need to monitor your warfarin while taking it.

What Are Antidepressant Medications?

A doctor prescribes an antidepressant medication to improve mood disorders like depression or anxiety. Although antidepressants cannot cure depression, it can help to relieve some symptoms. According to the National Institute of Mental Health, there are several different types of antidepressant medications. These medications primarily work on brain chemicals called neurotransmitters, like serotonin, norepinephrine, and dopamine.1

Interactions with Warfarin?

Some of the newest and most popular antidepressants are called selective serotonin reuptake inhibitors (SSRIs) or serotonin and norepinephrine reuptake inhibitors (SNRIs).2, 3 Older antidepressant medications include tricyclics, tetracyclics, and monoamine oxidase inhibitors (MAOIs).

Several studies have found that SSRIs were associated with an increased risk of bleeding in patients taking warfarin.4, 5, 6 Citalopram, nefazodone and sertraline may be less likely to interact with warfarin.7 While fluoxetine, fluvoxamine, paroxetine and moclobemide appear to have the highest potential of the antidepressants for interactions.7 Although the evidence does show a potential interaction, there was little information included in the studies to show if the patients were taking their medications properly, or how often their INR was tested.

The herbal medicine St. John's Wort has been used for centuries in many folk and herbal remedies. See our article on St. John’s Wort for more information about potential interactions with warfarin.

New Antidepressant Medications for 2014

In 2014, many new anti-depressant medications became available in the United States. Two of these new drugs include vortioxetine (Brintellix®) and Levomilnacipran (Fetzima®).

The new antidepressant Brintellix® is produced and co-marketed by the Lundbeck and Takedk pharmaceutical company.Brintellix is indicated to treat major depressive disorders in adults. The side effects are similar to many of the medications used to treat depression. The package insert for Brintellix did not show an interaction with warfarin nor the need to adjust the daily dose of warfarin when taking Brintellix.8

Fetzima® (Levomilnacipran), the other new antidepressant, is also approved for treatment of major depressive disorders. The package insert for Fetzima cautions patients against the increased risk of dangerous bleeding in patients taking warfarin, aspirin, or non-steroidal anti-inflammatory drugs.9

If you are taking warfarin and planning on talking with your doctor about starting an anti-depressant, begin by sharing that you are taking warfarin. Your physician may choose a medication with more study data about reducing bruising and bleeding risk to you. While it is your clinician’s job to choose the best medication for you, it is your job to openly and consistently communicate with them about different medications that you take.


  1. Depression. National Institute of Mental Health. Accessed Sept. 11, 2013.
  2. Hirsch M, et al. Selective serotonin reuptake inhibitors (SSRIs) for treating depressed adults. Accessed Sept. 11, 2013.
  3. Hirsch M, et al. Serotonin-norepinephrine reuptake inhibitors (SNRIs) and other antidepressants for treating depressed adults. Accessed Sept. 11, 2013.
  4. Wallerstedt SM, Gleerup H, Sundström A, Stigendal L, Ny L. Risk of clinically relevant bleeding in warfarin-treated patients: influence of SSRI treatment. Pharmacoepidemiol Drug Saf. 2009;18:412-416.
  5. Hauta-Aho M, Tirkkonen T, Vahlberg T, Laine K. The effect of drug interactions on bleeding risk associated with warfarin therapy in hospitalized patients. Ann Med. 2009;41:619-628.
  6. Schelleman H, Brensinger CM, Bilker WB, Hennessy S. Antidepressant-warfarin interaction and associated gastrointestinal bleeding risk in a case-control study. PLoS One. 2011;6(6): e21447. doi:10.1371/journal.pone.0021447.
  7. Duncan, D.; Sayal, K.; McConnell, H.; Taylor, D. Antidepressant interactions with warfarin. International Clinical Psychopharmacology. March 1998.
  8. 2014 Package insert. Brintellix (vortioxetine)
  9. 2014 Package insert. Fetzima, (levomilnacipra)

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