Abbott Laboratories (ABT) said it named a new head of its pharmaceutical unit.

The Abbott Park, Ill., health-care products company said in a regulatory filing Monday that it named Olivier Bohuon executive vice president of pharmaceutical products, effective Aug. 1. He was previously senior vice president of international pharmaceuticals.

Bohuon succeeds James Tyree, who will move to a new role as president of Abbott Biotech Ventures Inc., a unit that invests in early-stage pharmaceuticals and biologics.

Abbott's pharmaceutical unit is its biggest, contributing more than 55% of total company revenue. After a period of strong growth, the unit posted a sales decline for the first quarter, partly because of a slowdown in sales of its top product, Humira for rheumatoid arthritis and other conditions.

Tyree has had senior posts in the pharmaceutical unit since 2006. He was elected an Abbott corporate officer in 2001. Bohuon has held leadership posts in European and international operations since 2003, the year he was elected a corporate officer.

An Abbott spokesman wasn't immediately available.

Abbott shares fell 25 cents to $45.80 in recent trading.

-Peter Loftus, Dow Jones Newswires; 215-656-8289; peter.loftus@dowjones.com