Red has hit the market all over today, as the Dow Jones Industrial Average (^DJI 0.51%) plunged into the red from the opening bell and hasn't looked back. As of 2:45 p.m. EDT, the average was down more than 104 points, with all but a select few blue-chip stocks on the index taking losses so far. Big Pharma has suffered the worst today despite news on the acquisition front, with both Pfizer (PFE -1.16%) and Merck (MRK -0.58%) stock plummeting. Let's catch up on what you need to know.

Is GDP growth in trouble?
The day began with some good economic news, as data showed America's trade deficit closed by 3.6% in March. While that was a better result than economists had expected, the deficit amount still exceeded government predictions substantially – a worrying figure considering the meager 0.1% growth in U.S. gross domestic product through the first quarter. That now has some economists projecting GDP contraction in the second quarter, although others believe increased domestic energy production will keep narrowing the trade gap throughout the year. Either way, it's clear the economy needs to keep up its momentum as the worldwide recovery isn't on firm footing just yet.

Optimism is evading Big Pharma today, as Pfizer (PFE -1.16%)is down 1.8% after. The company's earnings release yesterday showed that Pfizer's interest in acquiring rival drugmaker AstraZeneca (AZN 1.03%) looks much more necessary than before. Revenue plunged 9% and earnings tumbled an even more drastic 15% year over year for Pfizer's most recent quarter, as generic competition and a loss of a sales deal for heavyweight rheumatoid arthritis drug Enbrel slammed the company's results. While Pfizer does have some beacons of hope in the darkness -- leading drug seller Lyrica continues to perform strongly -- the company's inability to turn around the revenue drop-off since former blockbuster Lipitor's patent expiration show that Pfizer's in need of a serious shake-up.

Does acquiring AstraZeneca pave the best route to injecting growth? Pfizer's current hopes for future results look muddled: The company and many investors are excited about developmental breast cancer drug palbociclib, which some analysts have seen hitting $4 billion in peak sales one day. Pfizer is also high on expanded usage of its Prevnar 13 vaccine in boosting sales, but will that be enough? AstraZeneca is doing all it can to fight off Pfizer's interest, as the British company today projected improved sales growth through 2023 and said that a Pfizer acquisition would harm the development of its vaunted pipeline. However, don't expect revenue-hungry Pfizer to turn away simply because AstraZeneca shook its head at the company's most recent offer. Expect this takeover saga to continue on.

Merck's shares have tumbled 2.6% so far. That drop-off came after Merck announced that German drug giant Bayer (BAYR.Y 3.73%) would buy the company's over-the-counter and consumer health business for $14.2 billion. It's a good deal for both companies: Bayer's acquisition brings in a bevy of new brands to the German company and allows for a much stronger push into the U.S. market. Merck, meanwhile, has struggled with earnings in recent quarters -- shedding the sizable business will allow it to cut costs and focus on its core drugmaking business.