PARIS — Sanofi-aventis has completed its acquisition of U.S. drug maker Chattem Inc., which is now a subsidiary of the sanofi-aventis Group.

Chattem’s common stock ceased trading on the Nasdaq Global Select Market after the market’s close on March 10, sanofi-aventis said Thursday. The Paris-based pharmaceutical giant announced the $1.9 billion deal in December and said it would create the world’s fifth-largest consumer health care company.

Now the U.S. consumer health care unit of sanofi-aventis, Chattem will still be based in Chattanooga, Tenn. Zan Guerry, chief executive officer of Chattem, will lead the U.S. consumer health care business and report to Greg Irace, president and CEO of sanofi-aventis U.S.

Sanofi-aventis noted that by strengthening its presence in the U.S. consumer health care market, which it said represents 25% of the current worldwide market, the company is building a significant platform for future growth. The acquisition also provides new channels for maximizing the potential of converting its prescription medicines to over-the-counter products, beginning with Allegra (fexofenadine hydrochloride), which is expected to be an important growth driver, sanofi-aventis added.

"The addition of Chattem to our worldwide portfolio of leading consumer health care businesses represents an important milestone in sanofi-aventis’ strategy to become a global diversified healthcare leader," stated Christopher Viehbacher, CEO of sanofi-aventis. "Chattem’s existing sales, marketing and distribution teams and infrastructure provide a tremendous platform for future conversions of prescription medicines to OTC products in the U.S., and I am confident that Chattem will maximize the success of those conversions. I look forward to working with Zan Guerry and the Chattem leadership team, who will play a key role in the performance of our consumer health care activities."

Sanofi-aventis also said it expects to obtain significant revenue synergies through the expansion of Chattem’s products into currently untapped geographic markets where sanofi-aventis has a strong operating presence.

"The entire Chattem team is excited to serve as the base for sanofi-aventis’ U.S. consumer health care business and looks forward to capturing the significant growth opportunities," commented Guerry.