Bayer's $14.2 billion acquisition of Merck's consumer care business on Tuesday pushed the value of pharmaceutical M&As to $239.1 billion so far this year.

Healthcare companies, under pressure from tougher reimbursement regulations in developed countries, are adding scale, picking up specialised expertise and shedding non-core businesses.

Here's a list of some of the major deals and offers this year:

MAY

May 6 - Merck & Co Inc (>> Merck & Co., Inc.) agrees to sell its consumer care business to Germany's Bayer AG (>> Bayer AG) for $14.2 billion.

May 2 - Pfizer Inc (>> Pfizer Inc.) raises its offer for AstraZeneca Plc (>> AstraZeneca plc) to 63 billion pounds ($106 billion), but the British company promptly rejects the proposal, which would create the world's biggest pharmaceuticals company.

APRIL

April 30 - Sanofi SA (>> SANOFI) is looking to sell a portfolio of older drugs that could fetch $7 billion to $8 billion, Reuters reports, citing people familiar with the matter.

April 28 - Allergan is preparing to approach Shire Plc (>> Shire PLC) about a potential takeover, even though the Irish drugmaker rebuffed a previous overture, Reuters reports, citing sources familiar with the matter.

Forest Laboratories Inc says it will buy Furiex Pharmaceuticals Inc (>> Furiex Pharmaceuticals Inc) for up to $1.46 billion, including milestone payments.

April 25 - U.S. generic drugmaker Mylan (>> Mylan Inc) makes new and improved bid for Meda (>> Meda AB), valuing its Swedish rival at around $9 billion including debt, Reuters reports, citing a source familiar with the matter.

April 24 - Zimmer Holdings Inc (>> Zimmer Holdings, Inc.) says it would buy rival orthopaedic products maker Biomet Inc for more than $13 billion.

April 22 - Canada's Valeant Pharmaceuticals International Inc (>> Valeant Pharmaceuticals Intl Inc) and activist investor Bill Ackman makes an unsolicited $47 billion bid to buy Botox maker Allergan Inc (>> Allergan, Inc.). The bid prompts Allergan to adopt a one-year stockholder rights plan to give it more time to consider takeover proposals.

Novartis (>> Novartis AG) and Britain's GlaxoSmithKline (>> GlaxoSmithKline plc) agree to trade more than $20 billion worth of assets to bolster their best businesses and exit weaker ones. Novartis also says it would sell its animal health arm to Eli Lilly (>> Eli Lilly and Co) for about $5.4 billion in cash.

April 7 - Specialty pharmaceuticals company Mallinckrodt Plc (>> Mallinckrodt PLC) says it will buy drugmaker Questcor Pharmaceuticals Inc (>> Questcor Pharmaceuticals Inc) for about $5.6 billion to gain access to its multiple sclerosis drug, Acthar Gel.

FEBRUARY

Feb. 24 - German drug firm Bayer clinches a $2.9 billion deal to take over Norwegian cancer drugmaker Algeta (>> Algeta ASA) after being tendered 92.17 percent of the shares in a cash offer.

Feb. 18 - Generic drugmaker Actavis Plc (>> Actavis PLC) says it will buy Forest Laboratories Inc (>> Forest Laboratories, Inc.) for about $25 billion in cash and stock, giving it a major focus on higher-margin, branded treatments for Alzheimer's, hypertension and other disorders.

Feb. 11 - Mallinckrodt says it will buy pain drug maker Cadence Pharmaceuticals Inc (>> Cadence Pharmaceuticals, Inc.) for about $1.3 billion to expand in the hospital market.

Feb. 3 - Britain's Smith & Nephew Plc (>> Smith & Nephew plc) says it will buy ArthroCare Corp (>> ArthroCare Corporation) for an agreed $1.7 billion in cash to strengthen its treatments for sporting injuries, an area growing faster than its main replacement hips and knees business.

JANUARY

Jan. 16 - Johnson & Johnson says it will sell its ortho clinical diagnostics unit to buyout firm Carlyle Group LP (>> The Carlyle Group LP) for $4.15 billion, shedding a slow-growing business to focus on more lucrative products.

Jan. 8 - Forest Laboratories Inc says it will buy specialty pharmaceutical maker Aptalis from private equity firm TPG Capital for $2.9 billion.

(Compiled by Esha Dey and Sriraj Kalluvila in Bangalore)