Drs Hincapie-Castillo and Vouri had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Objectives: To evaluate the prescription sequence symmetry analysis assumption regarding balance between marker drug (i.e., medication used to treat a drug-induced adverse event) initiation rates before and after initiation of an index drug (i.e., medication that is potentially associated with the drug-induced adverse event) in the absence of prescribing cascades, we used a well-described example of loop diuretic initiation to treat dihydropyridine calcium channel blockers (DH CCB)induced edema.