John Funkhouser, chief executive officer at PharmaNetics, has taken the firm’s dispute with partner Aventis Pharmaceuticals to a new, more bitter level.

PharmaNetics disclosed Tuesday that it had filed suit against Aventis, alleging that the pharmaceutical giant “has engaged in false and misleading advertising” about the safety of Lovenox.

In a statement, Funkhouser said: “We deeply regret that we have had to take this step. We have done everything in our power to convince Aventis that their promotion of Lovenox is improper and putting patient safety at risk. The lawsuit is the right thing for PharmaNetics and, more importantly, it’s the right thing for patients.”

The suit was filed Monday and disclosed Tuesday as PharmaNetics announced its third quarter results. The company said revenues climbed 17 percent to $1.4 million, a slight increase over a year ago. PharmaNetics posted a lost of $2 million, or 20 cents a share.

“Our contract with Aventis has been breached,” Funkhouser said, “and our best efforts to reach a mutual arbitrated settlement of our differences have been unsuccessful.”

Aventis reported last week that sales of Lovenox increased 26 percent in the third quarter.

The drug, which has sales of more than $1 billion a year and PharmaNetics says is the second biggest seller for Aventis, is used to treat heart patients.

PharmaNetics and Aventis struck a partnership under which PharmaNetics designed a test (called ENOX) to determine whether Lovenox could be used safely. But Funkhouser has been quite vocal in complaints that Aventis was not promoting and selling the test, which is crucial to the Raleigh-based firm’s growth.

PharmaNetics stock (Nasdaq: PHAR) dropped 19 percent, or 88 cents, to $3.72 on Tuesday.

Funkhouser said that Aventis is advertising the drug as “therapeutic from dose one” and “no monitoring required.” According to PharmaNetics, such claims are “putting the safety of patients at risk.”