(Reuters) - The antitrust division of the U.S. Department of Justice has subpoenaed Mylan N.V. for information relating to the pricing and marketing of its generic doxycycline antibiotic products, the drugmaker said on Friday.

The Department of Justice has also sought information on any communication with competitors about the anti-bacterial products, the company said in a regulatory filing, adding it would cooperate with the federal agency.

The nearly 40-year-old antibiotic is used to treat bacterial infections such as acne, pneumonia, Lyme disease, chlamydia and syphilis.

Competitors Endo International and Allergan Inc have also received similar subpoenas, according to regulatory filings made by them in November and August.

U.S. drugmakers have been under increased pressure from the government, insurers and corporations over steep increases in the prices of generic drugs.

Mylan shares were up 34 cents, or 0.7 percent, at $51.40.

In a research note, Susquehanna Financial Group analyst Andrew Finkelstein said he believed Mylan was not the main beneficiary of doxycycline price hikes, and that competitors Allergan, Sun Pharmaceutical Industries and Hikma Pharmaceuticals had raised prices the most. The biggest price gains were in the first half of 2013, he said, and have since eased.

Allergan, Sun Pharma and Hikma did not immediately respond to requests for comment.

Endo said in a November 2015 regulatory filing that it received a subpoena on Dec. 5, 2014 relating to communications with rivals regarding doxycycline and digoxin, a widely used generic drug used to treat heart failure.

Allergan said in August it had received a subpoena from the antitrust division relating to generic products and communications with competitors. It did not disclose which drugs were involved.

U.S. Senator Bernie Sanders and Democratic Representative Elijah Cummings opened an investigation last fall into 14 drug companies, including Mylan and Teva Pharmaceutical Industries, over price increases of generic drugs.

In February, Sanders and Cummings asked the U.S. Department of Health and Human Services' enforcement arm to investigate generic drug price increases. As an example, they cited doxycycline hyclate 100 milligram capsules, the price of which had more than doubled in the year through June 2014.

There are many forms of doxycyline made by more than a dozen companies, according to the U.S. Food & Drug Administration's database.

The discussion over drug pricing has intensified and become part of Presidential candidate Hillary Clinton's campaign after Turing Pharmaceuticals raised the price of a generic medication by 5000 percent in one day.

(Reporting by Caroline Humer in New York and Natalie Grover in Bengaluru; Editing by Bernadette Baum)