LONDON — Fears that a proposed $106 billion takeover of British pharmaceuticals firm AstraZeneca by Pfizer, its New York-based rival that makes the erectile dysfunction drug Viagra, would lead to job losses and tax sidestepping is ruffling political feathers on both sides of the Atlantic even as merger activity in the pharma sector hits record levels.

Since the start of the year, the value of deal-making maneuvers in the global pharmaceutical sector has hit nearly $240 billion, making 2014 the busiest year ever, according to Thomson Reuters data.

“What the Pfizer bid for AstraZeneca has done is to highlight that the next cycle in the bio-pharmaceutical business is M&A,” says Basil Petrides, an analyst at Beaufort Securities, a London-based wealth management company.

“There are always synergies to be had in terms of minimizing overlap, but the deals we have seen recently are not necessarily all about cost-cutting either,” he says. “Intellectual property rights on drugs only last for a certain amount of years and after that they are opened up to other manufacturers. Pfizer has been circling this deal for a long time. Its pipeline of drugs is slowly eroding and the easiest way to get value for shareholders is to take over companies that have ‘pipe’ and proven technology.”

In addition to Pfizer’s spurned cash and stock bid for AstraZeneca on May 2 — worth a bit less after shares in Britain’s second-largest drugs firm closed down 2.4% Friday — Germany’s Bayer agreed to purchase New Jersey-headquartered Merck’s consumer care business on May 6 for $14.2 billion.

On April 22, activist investor Bill Ackman teamed up with Canada’s Valeant Pharmaceuticals for a $47 billion bid for Allergen, the maker of Botox. That same day, Novartis of Switzerland and Britain’s GlaxoSmithKline said they would swap assets and combine units in a deal valued at around $16 billion.

Pfizer’s so-far rebuffed interest in AstraZeneca is confronting particularly intensive scrutiny in Britain though. The pharmaceutical industry is thought…