UPDATE 2-US FDA warns firms selling unapproved narcotics

* 14 pain drugs are widely used, FDA says

* Companies have 60 days to stop making the drugs

* No shortage expected as alternatives are available (Adds Boehringer comment)

WASHINGTON, March 31 (Reuters) - U.S. regulators warned nine companies on Tuesday to stop selling 14 unapproved narcotic pain medicines, part of an ongoing effort to rid the market of drugs without proper clearance.

Companies that received the warnings included Boehringer Ingelheim's Roxane Inc unit, Covidien Ltd's (COV.N: Quote, Profile, Research) Mallinckrodt unit and Glenmark Pharmaceuticals (GLEN.BO: Quote, Profile, Research).

The Food and Drug Administration said the widely used prescription medicines contained morphine, hydromorphone or oxycodone. Companies must stop manufacturing the unapproved versions within 60 days and stop shipments within 90 days.

The FDA said there were enough approved products with those pain-killing ingredients to meet patient needs and no shortage was expected.

Covidien will comply with the FDA's order and consider whether to seek agency approval to sell its product, a generic morphine solution, company spokesman Steve Littlejohn said. The product is not material to Covidien with annual revenue well below $10 million, Littlejohn said.

The drug's sales are not material to Covidien, he said.