Pfizer (NYSE: PFE), the world’s biggest drugmaker, will wean off of BlackBerry’s (Nasdaq: BBRY) phones, citing concerns that the mobile technology company might not be around in the future or may have service interrupted.

Pfizer told employees who use BlackBerry devices to instead get an Apple Inc. phone or one run on Google Inc.’s Android operating system. The drugmaker cited Waterloo, Ontario-based BlackBerry’s declining market share and noted that the company attempted to sell itself.

“In response to declining sales, the company is in a volatile state,” New York-based Pfizer told employees in a memo obtained by Bloomberg News. “We recommend that BlackBerry clients use their BlackBerry devices and plan to migrate to a new device at normal contract expiration.”

Both companies maintain a presence in North Carolina. BlackBerry operates two research and development offices in Cary.

Pfizer operates a huge manufacturing facility in Sanford.

It recently spun off an animal health group that includes operations in North Carolina. Among those holdings was the former poultry health firm Embrex. Pfizer bought the company in 2006 for $155 million.

After years of losing customers to Apple’s iPhone and devices running Android, BlackBerry is struggling to keep remaining users from defecting. The new BlackBerry 10 operating system, meant to fuel a comeback, drew a tepid response from buyers, and the company had to write off almost $1 billion in unsold inventory last quarter.

Pfizer had 92,000 employees as of its last annual filing, making it the eighth-biggest employer among U.S. and Western European-based health-care companies, according to data compiled by Bloomberg. Contingency plans have been developed in case BlackBerry shuts down or is unable to provide services, Pfizer said in the memo.

“We never go out in the media and talk about our service providers,” said Joan Campion, a Pfizer spokeswoman.

A $4.7 billion takeover bid for BlackBerry was scrapped this month, prompting a shakeup at the company. BlackBerry installed former Sybase Inc. Chief Executive Officer John Chen as the head of the company and raised $1 billion in convertible debt to help bolster its disappearing cash.

In a blog post on Nov. 13, Chen tried to reassure customers that the company is not going anywhere.

“We also want our customers to know that BlackBerry has significant financial strength for the long-haul,” he said. “I am confident that we will rebuild BlackBerry for the benefit of all of our constituencies.”