The drugmaker Merck & Co. will lay off 500 people from its facility in West Point, Montgomery County, between Dec. 23 and Jan. 5.

Merck said on Oct. 1 that it would eliminate 8,500 jobs from its worldwide workforce beyond the 7,500 it had not yet cut from an earlier restructuring plan, but company officials were not specific about where and when.

Several big pharmaceutical companies with operations in the area are cutting jobs. Message boards devoted to Merck have been full of discussions about which units would lose people, but official public notice of the 500 job cuts at the West Point facility came because of a federal law called the Worker Adjustment and Retraining Notification Act (WARN).

The law is intended to give workers notice of impending layoffs at companies with more than 100 full-time employees. Merck this week posted a WARN notice on the Pennsylvania Department of Labor website.

"We are committed to managing these separation aspects with dignity and respect for our employees, with the greatest expedience and will provide appropriate support during this transition," spokeswoman Lainie Keller said Friday evening in an e-mail in response to questions, including about the timing of the holiday layoffs.

Keller declined to specify which divisions at West Point would have layoffs. "I don't have details on any further reductions at this time," she said in the e-mail.

Merck has been under pressure from Wall Street investors to produce more revenue and profits than it has in recent years. Philadelphia native and chief executive officer Ken Frazier named a new leader of research and development early in 2013, but medicine can take a decade to go from the laboratory to a pharmacist's shelf. Besides the recently announced layoffs, Frazier said Merck was accelerating the closure of facilities. In October 2012 Merck said it would move its headquarters from Whitehouse Station, N.J., to Summit, N.J., but that plan was scrapped Oct. 1. The Summit facility will also close, and headquarters functions will move into the Merck facility in Kenilworth, N.J.