Table 2.

Top ten severe potential DDIs (severe and contraindicated).

Type	Effect	n	Interaction (%)	Patient (%)
Citalopram/ Anti-platelet	Concurrent use may result in an increased risk of bleeding. (Documentation: Good)	21	6.7	11.6
Clopidogrel/ Omeprazole	Concurrent use may result in reduction in clinical efficacy of clopidogrel and increased risk of thrombosis. (Documentation: Excellent)	11	3.5	6.1
Clopidogrel/ Aspirin	Concurrent use may result in an increased risk of bleeding. (Documentation: Fair)	10	3.2	5.5
Citalopram/ Omeprazole	Concurrent use may result in increased citalopram exposure and risk of QT interval prolongation. (Documentation: Fair)	8	2.5	4.4
Escitalopram/ Anti-platelet	Concurrent use may result in an increased risk of bleeding. (Documentation: Good)	5	1.6	2.7
Citalopram/ Quetiapine	Concurrent use may result in increased risk of QT interval prolongation. (Evidence level: Fair)	5	1.6	2.7
Paroxetine/ Anti-platelet	Concurrent use may result in an increased risk of bleeding. (Documentation: Good)	4	1.3	2.2
Amlodipine/ Clopidogrel	Concurrent use may result in decreased antiplatelet effects and increased risk of thrombotic events. (Documentation: Excellent)	3	0.3	1.6
Citalopram/ Risperidone	Concurrent use may result in increased risks of QT interval prolongation and torsade de pointes. (Documentation: Good)	3	0.3	1.6
Citalopram/ Haloperidol	Concurrent use may result in an increased risk of QT interval prolongation. (Documentation: Good)	3	0.3	1.6

Documentation: Excellent (controlled studies have clearly established the existence of the interaction), Good (documentation strongly suggests that the interaction exists, but well-controlled studies are lacking), Fair (available documentation is poor, but pharmacologic considerations have led clinicians to suspect that the interaction exists; or the documentation is good for a pharmacologically similar drug), and Unknown (Unknown). The documentation is based on information obtained from Micromedex^®.