Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

Has Washington finally found a cure to the political mess that has gripped Capitol Hill all through October? Wall Street thinks so, as stocks have zoomed higher today, with the Dow Jones Industrial Average (^DJI 0.69%) surging about 155 points as of 2:35 p.m. EDT. The Dow started the day with a bang and hasn't looked back after the Senate leaders reached an agreement to end the federal government shutdown; the measure still has to pass both chambers.

Most stocks on the Dow are in the green today, and the index's four health care members have all pushed into higher territory. Pfizer's (PFE 0.23%) among the Dow's best today, up 2%, but rival Merck (MRK -0.05%) is lagging somewhat with a 0.75% gain. Let's catch up on the Dow action you need to know about.

Pfizer leaps up the charts
Pfizer stock hasn't exactly been one of the Dow's best picks lately, having lost more than 5% over the past six months and ranking in the blue-chip index's bottom half through 2013. The patent cliff has hit virtually every member of big pharma lately, but despite Pfizer's inability to keep up with the Dow's leaders this year, this company's done well in handling tough patent expirations and their hits to sales.

Lipitor's been Pfizer's biggest loss. The anticholesterol drug's patent loss last year has been a big part of why Pfizer's sales plunged around 9% over the first six months of the year. Lipitor's revenue dived 55% over the first half of the year, but Pfizer's Lyrica, its current top seller, has helped pick up some of the slack. Still, it's the long term that investors should be focused on, and Enbrel, one of Pfizer's best-sellers, still has plenty of time ahead of it before it loses patent protection.

Pfizer boasted 18 drugs in phase 3 trials as of May 9, and even if it doesn't hit on all of those, that's a great cushion to fall back on as the company looks to bring a new wave of drugs to market to jump-start its lagging revenue. With a strong dividend in hand, this is a stock that can appeal to all kinds of investors.

That's certainly a better outlook than over at competitor Merck. While Merck's lost a comparable amount of its revenue over the first half of the year, the company's prospects are murky.

Zetia, Vytorin, and Nasonex, three of Merck's strongest drugs that pulled in nearly $3 billion worth of revenue over the first half of 2013, could all see generic competition trickle in by 2018. While Merck's diabetes duo of Januvia and Janumet continue to pull the most weight for this company, tough competition, particularly in the form of Johnson & Johnson's hyped diabetes treatment Invokana, could threaten their reign atop this growing market.

Merck does boast one of the stronger dividends in Big Pharma, but with several of its top drugs threatened by patent expirations in the near future and a lackluster pipeline, conservative investors should watch this health care giant with a cautious eye.