Escitalopram, similarly to other SSRIs, may increase bleed risk with NSAIDs (ibuprofen, naproxen, mefenamic acid), antiplatelet drugs, anticoagulants, omega-3 fatty acids, vitamin E, and garlic supplements due to escitaloprams inhibitory effects on platelet aggregation via blocking serotonin transporters on platelets. Escitalopram inhibits CYP2D6, and hence may increase plasma levels of a number of CYP2D6 substrates such as aripiprazole, risperidone, tramadol, codeine, etc. As escitalopram is only a weak inhibitor of CYP2D6, analgesia from tramadol may not be affected. Escitalopram should be taken with caution when using St. Johns wort, ginseng, dextromethorphan (DXM), linezolid, tramadol, and other serotonergic drugs due to the risk of serotonin syndrome. Exposure to escitalopram is increased moderately, by about 50%, when it is taken with omeprazole. The authors of this study suggested that this increase is unlikely to be of clinical concern.
Bupropion has been found to significantly increase citalopram plasma concentration and systemic exposure;  the interaction with escitalopram had not been studied, but some monographs warned of the potential interaction.
Escitalopram can also prolong the QT interval, and hence it is not recommended in patients that are concurrently on other medications that also have the ability to prolong the QT interval. These drugs include antiarrhythmics, antipsychotics, tricyclic antidepressants, some antihistamines (astemizole, mizolastine), macrolide and fluoroquinolone antibiotics, some 5-HT receptor antagonists (except palonosetron), and some antiretrovirals (ritonavir, saquinavir, lopinavir). As an SSRI, escitalopram should not be given concurrently with MAOIs.