* Weekly jobless claims fall to 249,000 vs. est. 257,000
* Wal-Mart top drag on S&P, Dow
* Pfizer falls after deal to sell infusion therapy business
* Indexes down: Dow 0.44 pct, S&P 0.27 pct, Nasdaq 0.35 pct (Updates to open)
By Yashaswini Swamynathan
Oct 6 (Reuters) - Wall Street was lower on Thursday as healthcare stocks slipped, while strong economic data raised the prospects of tighter monetary policy.
A report showed the number of Americans filing for unemployment benefits fell last week to a near 43-year low. The data comes ahead of a crucial monthly jobs report that will influence the Federal Reserve's decision on interest rates.
A growing number of Fed officials have argued for higher rates as the labor market remains robust and inflation inches towards the central bank's 2 percent target.
"Good economic news will be bad news for the markets," said Phil Davis, managing partner at PSW Investments in PSW Investments in Woodland Park, New Jersey.
Traders raised the odds of a rate hike to 64 percent for December, up from 60 percent before the jobless claims report was released, according to the CME Group's FedWatch tool.
At 9:38 a.m. ET (1338 GMT), the Dow Jones Industrial Average was down 80.26 points, or 0.44 percent, at 18,200.77.
The S&P 500 was down 5.73 points, or 0.27 percent, at 2,154.
The Nasdaq Composite was down 18.74 points, or 0.35 percent, at 5,297.28.
The S&P healthcare sector fell 0.82 percent and weighed the most on the benchmark index.
Johnson & Johnson shares fell 0.9 percent after the U.S. Department of Homeland Security issued a warning on the company's insulin pumps.
Pfizer fell 1.06 percent after agreeing to sell its infusion therapy business to ICU Medical Inc for $1 billion in cash and stock.
Eight of the 11 major S&P 500 sectors were lower, with real estate falling the most by 1.04 percent.
Energy and financials were the bright spots.
Wal-Mart dropped 2.6 percent to $69.76 and was the top drag on the S&P and the Dow after the world's largest retailer forecast flat earnings for next year.
Twitter shares plunged 16.4 percent to $20.76 after technology news website Recode said Disney and Alphabet were not in the race for the company.
Alnylam dropped 47.8 percent after it abandoned testing its experimental drug for heart failure as trial data showed patients who took the treatment were more likely to die than those who got a placebo.
Declining issues outnumbered advancing ones on the NYSE by 1,805 to 820. On the Nasdaq, 1,518 issues fell and 665 advanced.
The S&P 500 index showed seven new 52-week highs and five new lows, while the Nasdaq recorded 22 new highs and 10 new lows. (Reporting by Yashaswini Swamynathan in Bengaluru; Editing by Anil D'Silva)