Differential Impact of Selective Serotonin Reuptake Inhibitors on Platelet Response to Clopidogrel: A Randomized, Double-Blind, Crossover Trial

SSRIs and other antidepressant medications constitute one of the most commonly prescribed drug classes that pharmacists will see in the community setting. When taken alone, any one of these medications can be a good treatment option for patients experiencing depression; however, these drugs can cause a patient who is taking multiple drugs  to experience significant interactions with his/her other medications. For this reason, it is crucial to know how the effects of other medications can be altered through this therapy.  This study analyzed the effects of two SSRIs (citalopram and fluvoxamine) on the blood thinning medication clopidogrel. These medications all work on the same CYP enzyme (CYP2C19)  and have opposing effects. Researches tested these medications on healthy individuals and found that fluvoxamine was the only drug that caused significant inhibition of clopidogrel action.

I think this is important to note because these medications are commonly utilized by patients and thus there is a high likelihood that they may be taken together. As pharmacists, we should be able to provide adequate care in response to possible drug-drug interactions. To do this, we have to be able to recognize when there could potentially be a problem in medication therapy. By taking the proper precautions when these situations arise, pharmacists will be more likely to help patients avoid adverse medical events associated to drug therapy methods.

PPI–clopidogrel interaction a concern after stent placement

The goal of this study was to determine if there was an increased risk of adverse cardiac events in patients with DM2 who were using clopidogrel and a PPI concomitantly following drug-eluting stent placement(DES).

There were roughly 10,000 patients in this study, with the clinical endpoints of the study being whether patients with DES who were either using clopidogrel alone or in combination with a PPI experienced acute coronary syndrome and readmission to the hospital due to revascularization after 3,6, or 12 months.

The researchers found that patients using the combination of drugs had a 6 month hazard ratio of 1.63 and a 12 month hazard ratio of 1.37. Patients who had previous history of acute coronary syndrome who received the drug combination were at a higher risk of ACS following stent placement(1.55 times more likely) than those who received clopidogrel alone.

I think this study is very interesting because many patients will be using a PPI while also using an anti-platelet drug such as clopidogrel. What is also concerning is that if patients are not counseled on the increased risk of ACS when combining these two drugs, patients can elect to purchase an OTC PPI on their own, and may unknowingly subject themselves to this risk. I think that this drug interaction may be an important point for pharmacsists to counsel on when first dispensing clopidogrel to patients.

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