PARIS — Sanofi has agreed to a 22.8 billion euro ($25.1 billion) asset swap with Germany’s Boehringer Ingelheim GmbH that will boost the French drug manufacturer’s business in selling over-the-counter drugs.

The two companies reached a definitive agreement late Monday after announcing exclusive negotiations in December. Terms are unchanged from the original announcement: Sanofi will trade its Merial animal health business for Boehringer’s consumer health operation.

Boehringer will also pay Sanofi 4.7 billion euros in cash.

The deal helps chief executive officer Olivier Brandicourt reshape Sanofi, whose pharmaceuticals division has encountered declining sales of its best-selling insulin. It also adds to the consolidation in consumer health. GlaxoSmithKline PLC and Novartis AG created a joint venture in 2015; Bayer AG acquired Merck & Co.’s O-T-C business in 2014.
The companies aim to complete the transaction by the end of the year.

Sanofi will use part of the proceeds to buy back shares, and it expects the deal to be neutral for earnings next year and add to profit after that, the company said.

The leading brands of Boehringer’s consumer health care business are the antispasmodic Buscopan, the laxative Dulcolax, the multivitamins Pharmaton, the cough treatments Mucosolvan and Bisolvon, and the sore throat treatment Mucoangin/Lysopaïne.

Sanofi’s leading O-T-C brands include the allergy products Allegra and Nasacort; the painkillers Doliprane, No-Spa and Dorflex; the digestive products Essentiale, Enterogermina and Maalox; the feminine care product Lactacyd; and the vitamins, minerals and supplements Magné B6.