On Jan. 23, 2008, the pharmaceutical company Novartis threw a party at a restaurant on Long Island. The party, which cost $1,250, was ostensibly for doctors to learn about cardiovascular drugs made by the company, with Novartis sales representatives present as well.

But no doctors ever came, according to a whistleblower lawsuit against Novartis that was unsealed last week. Instead, nine sales reps ran up the tab, and the company wrote an honorarium check to Dr. Robert Nissan, a Long Island family practitioner who wasn’t present, the lawsuit alleges.

The party, the lawsuit maintains, was one of “countless” events held by Novartis over a decade that were designed to direct kickbacks — cash, meals and favors to relatives — to doctors who prescribed the company’s drugs.

Last week, the Department of Justice joined the whistleblower lawsuit, which was originally filed in 2011 by Oswald Bilotta, a former Novartis sales representative on Long Island. “Novartis corrupted the prescription drug dispensing process with multi-million dollar ‘incentive programs’ that targeted doctors who, in exchange for illegal kickbacks, steered patients toward its drugs,” Preet Bharara, the U.S. attorney for the Southern District of New York, said in a statement.

Novartis has disputed the government’s allegations of wrongdoing; Nissan did not return several requests for comment.

Whether such payments by drug companies to physicians are kickbacks or a legitimate marketing and educational practice is a recurring controversy — as ProPublica has extensively reported. Our Dollars for Docs database tracks $2 billion in payments to doctors from 15 drug companies, including Novartis. All but one have settled government lawsuits alleging improper marketing practices.

A number of the doctors named in the Novartis case have received substantial sums since 2009, Dollars for Docs shows, including one physician who was paid more than $150,000 combined from six different drug companies.

Historically, the doctors cited in cases alleging improper marketing have not faced consequences. A ProPublica investigation in 2011 found that none of more than 75 doctors named in lawsuits since 2008 had been sanctioned, despite charges of fraud or conduct that put patients at risk.

Generally, payments like those in Dollars for Docs made for speaking, consulting, travel, meals and other promotional purposes are legal.

Novartis has only publicly reported payments since 2010, when the company pleaded guilty to a misdemeanor and paid $422.5 million to settle charges it had illegally promoted Trileptal, an anti-seizure drug, and had paid kickbacks for prescribing its drugs. Aside from the misdemeanor plea, Novartis denied wrongdoing.

The latest lawsuit is one of two filed last week by the Justice Department against Novartis in U.S. District Court in Manhattan. The company is also accused of paying kickbacks to pharmacies to promote Myfortic, a drug that suppresses the immune system. Novartis — which is bound by a corporate integrity agreement from its 2010 settlement — has disputed the allegations in both cases.

“We disagree with the way the government is characterizing our conduct in both of these matters and we stand behind our Compliance program,” Andre Wyss, the head of Novartis’s U.S. operations, said in a statement.

The whistleblower lawsuit alleges that Lotrel, a blood-pressure medication with sales of nearly $1.3 billion in 2006, “became a big seller for NOVARTIS because it paid physicians to write Lotrel prescriptions.” Novartis sales reps allegedly rewarded doctors with cash or gift checks and recruited them to attend “Clinical Learning Days” with honoraria of $250 to $500 a pop.

The meetings could be as short as half an hour, the whistleblower suit alleges, and doctors would be paid even if they didn’t show up. “So long as a physician was writing Lotrel prescriptions,” it says, “he or she could expect to be paid.”

Thousands of doctors took part in the alleged kickback scheme, according to the whistleblower lawsuit. But the case singles out 24 Long Island doctors and nurses, including Nissan. Nissan and two other physicians — Edward Condon, who specializes in internal medicine, and Mark Jagust, a family practitioner — “each received tens of thousands of dollars” from Novartis, according to the lawsuit.

Novartis also hired Ross Fishberger — the son of Kenneth Fishberger, another one of the doctors named — as a sales representative “in order to assure that Dr. Fishberger continued to prescribe” Lotrel and other Novartis drugs, according to the lawsuit. Novartis also allegedly employed Condon’s wife and daughter-in-law as sales reps.

Reached by ProPublica, Condon said he had no knowledge of the lawsuit, and hung up when asked more detailed questions. Jagust and the elder Fishberger did not respond to repeated requests for comment.

Ross Fishberger declined to comment when reached by ProPublica.

Dollars for Docs shows that drug companies have made payments to many of the 24 doctors named in the whistleblower lawsuit since 2009.

Condon received at least $156,094 in meals, travel, speaking fees and other expenses from six companies, including Novartis. Another doctor, Michael Shanik of Smithtown, N.Y., was paid at least $97,754 from six companies, including more than $30,000 from Novartis.

Robert Mormando, an internal medicine specialist in Port Jefferson Station, N.Y., who was also named in the case, told ProPublica he hadn’t taken any kickbacks and didn’t know of Long Island doctors who had.

“I would say it’s up for interpretation whether paying someone to be part of a speaking program” constitutes a kickback, he said. “I’m not aware of any doctors who have taken it to that level.”

Mormando said he had been a paid speaker for Novartis on three occasions a number of years ago and estimated he had earned between $1,200 and $1,500. According to Dollars for Docs, he was paid at least $9,958 from nine pharmaceutical companies since 2009, only $19 of which came from Novartis.

Another of the named doctors, Howard Hertz of Babylon, N.Y., also denied taking kickbacks in a brief interview. Hertz was paid at least $9,888 since 2010 from five drug companies, including $4,110 from Novartis, according to Dollars for Docs.

The main plank of the Justice Department’s lawsuit is the federal anti-kickback statute, which makes it illegal for drug companies to pay doctors with the intent of getting them to prescribe a particular drug or to reward them for doing so.

Kevin Outterson, a professor at Boston University Law School who has studied health care fraud, said it can difficult to prove intent in pursuing kickback cases.

“What it boils down to is they need smoking gun evidence,” he said.

But Outterson said he thought the Justice Department had a strong case. “It goes directly to the culture of wining and dining and having lavish entertainment and educational events in order to induce prescription writing,” he said.