However, many people are not aware that Serotonin plays a role in the clotting of blood by assisting in the aggregation of platelets. Some researchers are concerned that these antidepressants, most especially the Selective Serotonin Reuptake Inhibitors (SSRIs), may be interfering with the body’s ability to adequately form blood clots and increasing the risk for abnormal bleeding.
A study examining this possibility was ledby E.R. Heerdink, a researcher at the Utrecht Institute for Pharmaceutical Sciences in The Netherlands. His research team evaluated about 64,700 participants who received their first antidepressant prescription between 1992 and 2000. During the evaluation period averaging 229 days, 196 participants were admitted to hospitals for abnormal bleeding. Dr. Heerdink writes, "We think this [bleeding] is a serious side effect of some antidepressants, but it will mostly affect patients who are already at higher risk for bleeding" (Doheny, K., 2004).
Kathleen Doheny further reports on Dr. Heerdink’s findings, “Among the 196 persons in the study admitted to the hospital with abnormal bleeding, the risk of hospitalization increased with the use of the strongest SSRI antidepressants - that is, those that produce the most inhibition of serotonin reuptake. The risk of being hospitalized for bleeding was twice as high in drugs that produce intermediate inhibition, and about 2.6 times as likely for the drugs that produce high degrees of inhibition.”
Antidepressants with Intermediate Effects
- Venlafaxine (Effexor) - Atypical
- Dothiepin (Prothiaden) - Tricyclic
- Amitriptyline (Elavil) - Tricyclic
- Fluvoxamine (Luvox) - SSRI
- Imipramine (Tofranil) - Tricyclic
- Citalopram (Celexa) - SSRI
Antidepressants with High Effects
- Paroxetine (Paxil) - SSRI
- Clomipramine (Anafranil) - Tricyclic
- Sertraline (Zoloft) - SSRI
- Fluoxetine (Prozac) - SSRI
It is important to note that this one study found that less than 1% of its participants developed bleeding difficulties. While those now taking these antidepressants certainly need to be aware of this possibility, there is no need for alarm. A great deal more research is needed. Dr. Michael Stefan, former chief of staff and an internist at St. Vincent Medical Center in Los Angeles, said "the study results are certainly no cause for alarm for those on antidepressants. Advice about taking them wouldn't change based on one study, he emphasized" (Doheny, K., 2004).
Reference
Doheny, K. (2004, November 22). Antidepressants tied to abnormal bleeding. Forbes.
