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

Pfizer's $106 billion bid for AstraZeneca tops the list of healthcare deals and offers this year:

U.S. drugmaker Pfizer Inc raised its offer for AstraZeneca Plc to 63 billion pounds ($106 billion) on May 2, but the British company promptly rejected the proposal, which would create the world's biggest pharmaceuticals company.

Canada's Valeant Pharmaceuticals International Inc and activist investor Bill Ackman made an unsolicited $47 billion bid to buy Botox maker Allergan Inc on April 22, as it seeks to become one of the world's five biggest drug companies.

The offer prompted Allergan to adopt a one-year stockholder rights plan to give it more time to consider takeover proposals.

Allergan is preparing to approach Shire Plc about a potential takeover, even though the Irish drugmaker rebuffed a previous overture, Reuters reported on April 28, citing sources familiar with the matter.

Generic drugmaker Actavis Plc said on February 18 that it would buy 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.

Merck & Co Inc agreed to sell its consumer care business to Germany's Bayer AG for $14.2 billion, the companies said on May 6.

Zimmer Holdings Inc said on April 24 it would buy rival orthopedic products maker Biomet Inc for more than $13 billion, making Zimmer the second-largest seller of orthopedics products, behind Johnson & Johnson.

Swiss drugmaker Novartis and Britain's GlaxoSmithKline agreed to trade more than $20 billion worth of assets on April 22 to bolster their best businesses and exit weaker ones.

In addition, Novartis was selling its animal health arm to Indianapolis-based Eli Lilly for about $5.4 billion in cash.

U.S. generic drugmaker Mylan made a new and improved bid for Meda, valuing its Swedish rival at around $9 billion including debt, Reuters reported on April 25, citing a source familiar with the matter.

Sanofi SA is looking to sell a portfolio of older drugs that could fetch $7 billion to $8 billion, Reuters reported on April 30, citing people familiar with the matter.

Specialty pharmaceuticals company Mallinckrodt Plc will buy drugmaker Questcor Pharmaceuticals Inc for about $5.6 billion to gain access to its multiple sclerosis drug, Acthar Gel, which is set to hit sales of $1 billion this year.

Dublin-based Mallinckrodt's bought Cadence Pharmaceuticals Inc for $1.3 billion in February.

Johnson & Johnson said on January 16 it would sell its ortho clinical diagnostics unit to buyout firm Carlyle Group LP for $4.15 billion, shedding a slow-growing business to focus on more lucrative products.

Drugmaker Forest Laboratories Inc said in January it would buy specialty pharmaceutical maker Aptalis from private equity firm TPG Capital for $2.9 billion in a deal it promised would increase next year's earnings.

German drug firm Bayer clinched a $2.9 billion deal to take over Norwegian cancer drugmaker Algeta after being tendered 92.17 percent of the shares in a cash offer, the companies said on February 24.

Britain's Smith & Nephew Plc said on February 3 it would buy ArthroCare Corp 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.

Forest Laboratories Inc said on April 28 it would buy Furiex Pharmaceuticals Inc for up to $1.46 billion, including milestone payments, to add a promising treatment for irritable bowel syndrome to its gastrointestinal drugs portfolio.

U.S. drug distributor McKesson gained control of German peer Celesio as part of its drive to become a global leader in drugs distribution and boost its bargaining power with pharmaceutical firms.

A previous bid had foundered after failing to secure the 75 percent shareholder support it had set as a condition.

(Compiled by Esha Dey in Bangalore)