Despite insistent reports that e-commerce giant and Action Alerts Plus holding Inc. (AMZN - Get Report) is getting into the pharmacy business, wholesale drug distributor Cardinal Health Inc.  (CAH - Get Report) said it isn't worried about the potential threat.

"The way we interact with customers is very different from other vendors," said Jorge Gomez, Cardinal's chief financial officer, at the RBC Healthcare Conference in New York on Wednesday, Feb. 21,  noting that it typically interacts with its customers every day. "We have the clinical knowledge, the regulatory knowledge and the legal knowledge to manage orders ... and to get the best possible cost equation for our customers."

Cardinal's stock (and those of other medical suppliers) tumbled on Feb. 13 when Amazon announced it was partnering with Action Alerts Plus holding JPMorgan Chase & Co.  (JPM - Get Report) and Warren Buffett's Berkshire Hathaway Inc.  (BRK.B - Get Report) to create a non-profit healthcare company to improve services for the three companies' employees. Cardinal's stock has since recovered, however.

Gomez was asked about the specific risk from Amazon to Cardinal's EdgePark Medical Supplies business, which distributes health care products to the home. He argued that Cardinal manages the purchasing and approvals process in a way that would be hard for another vendor to duplicate. For example, most of the sales in that business are non-cash and need to be approved and reimbursed by insurance companies.

Gomez also noted that Cardinal has businesses outside the U.S. that aren't exposed to competition from Amazon.

"There's a lot of noise there; we don't see our customer base interacting with Amazon," Gomez said. "We know there are meetings that take place, but we don't run into them with RFPs."

Cardinal's stock was trading flat on Wednesday at $68.73; shares have risen 12% year to date.