PARIS — Sanofi-aventis has initiated its tender offer to buy all outstanding common shares of Chattem Inc. as part of its $1.9 billion deal to acquire the Chattanooga, Tenn.-based drug maker.

The French pharmaceutical giant said Monday that the offer, at $93.50 per share, is being made through its River Acquisition Corp. subsidiary. The tender offer is set to expire at midnight EST on February 8, barring an extension.

With the successful completion of the tender offer, plans call for River Acquisition Corp. to merge with and into Chattem and the outstanding Chattem shares not tendered in the offer to be converted into the right to receive the same $93.50 per share in cash paid in the tender offer, according to sanofi-aventis.

In announcing the acquisition late last month, sanofi-aventis said the deal would create the world’s fifth-largest consumer health care company.

And on Monday, sanofi-aventis noted that the transaction marks a milestone in its transformational strategy. The company said that by expanding its presence in the U.S. consumer health care market, which represents 25% of the current global opportunity, it is bolstering its position as a global, integrated health care company as well as creating a springboard for for future growth.