The new Consumer Healthcare Great Britain and Ireland business will have retail sales of more than £1bn and become operational from January next year.
As part of the shake-up, Peter Harding, vice president and general manager for GSK Nutritional Healthcare, will become general manager of the new business, which will bring together brands including Lucozade, Ribena, Sensodyne, Aquafresh, Panadol and NiQuitin.
Jon Workman, who was vice president for sales for the Nutritional Healthcare business, will assume the same role in the newly created division. He joined GSK last December from Procter & Gamble where he spent 15 years in sales and marketing roles.
Harding said the combined business would allow the group to drive aggressive category growth by delivering innovative products to market that were "rooted in science".
"Our reorganisation will simplify the way we serve our retail partners through our points of contact and allow us to use our resources more flexibly to meet their needs," he said. "Our aim is to work with retailer partners to grow their businesses alongside our own."
In April, GSK announced its intention to divest non-core brands to focus on four categories nutrition, wellness, oral care and skin health.
The products to be divested following the merger are primarily sold in Europe and the US. Theyinclude analgesics Solpadeine, BC and Goody's; vitamin and supplement product Abtei; feminine hygiene product Lactacyd; and weight management product Alli.
They had sales of about £500m last year 10% of GSK's total Consumer Healthcare turnover.
GSK said it intended to secure a buyer for the brands by the end of the year and expected the number of jobs lost as result of the merger to be "less than a handful".