When the pharmaceutical company Allergan Inc. was sued last month, it never considered a quiet settlement. Instead, it took the unusual step of firing off a pre-emptive press release.

One reason was the product, Botox; another, the plaintiffs, Irena and Mike Medavoy. Together they guaranteed this would not be a quiet case.

Botox is the California-based company's biggest seller, taking in $440 million last year. Though 60 percent is attributable to therapeutic use for muscle disorders, the drug is better known for cosmetic use. A purified form of the toxin that causes botulism, Botox temporarily and partially paralyzes muscles and can smooth away wrinkles when injected into a patient's face. It has many fans in Hollywood.

Not coincidentally, Mike Medavoy is a Hollywood mover and shaker. He's the current chairman of Phoenix Pictures and was chairman of Tri-Star and Orion.

If this didn't guarantee publicity -- whether the company wanted it or not -- Allergan's co-defendant is Dr. Arnold W. Klein, a dermatologist whose patients include Elizabeth Taylor and Michael Jackson, among other stars.

Last March, Medavoy's wife, Irena, sought treatment from Klein for migraine headaches. He injected her with Botox, which Allergan General Counsel Douglas Ingram said has been used by physicians for this purpose since the mid-1990s. According to the Medavoys' complaint filed in Los Angeles Superior Court (Medavoy v. Klein, No. SC075614), Irena Medavoy became "extremely ill," suffering from continued migraines, fever, respiratory problems and hives. Some symptoms eventually subsided, but many allegedly did not.

Solo practitioners Arthur Leeds and Robert Petrokofsky allege in the complaint that Allergan improperly promoted this so-called off-label use of the drug, which is not approved by the Federal Drug Administration for treatment of migraines. Furthermore, they allege, Klein did not fully inform his patient of the potential dangers of such treatment, nor did he disclose that he's a paid consultant to the company. Mike Medavoy allegedly suffered a "loss of comfort, companionship, intimacy" in his relationship with his wife. Both asked for unspecified compensatory damages; Irena Medavoy requested punitives for misconduct and fraud.

"It is common practice to use medications off-label," countered Klein's lawyer, Howard Weitzman of the Los Angeles office of New York's Proskauer Rose. "That's what they do in clinical studies. That's the way the drugs get tested."

Ingram noted that Botox is currently in clinical trials for treatment of headaches. In response to Petrokofsky's allegation, in an interview, that the information on the company's several Web sites concerning off-label use violates 21 U.S.C. 360, Ingram said: "He misunderstands the law. There's a lot of case law, comment and literature on this area."

Allergan has publicized the case not only because it recognized publicity was inevitable, Ingram said, but to reassure the public that Botox is safe. It's been used to treat millions of people for a host of problems over 20 years, he said, and this is the first lawsuit.

One unusual aspect of the case, Ingram said, is that the drug's effects, whether intended or not, are almost invariably temporary. Yet lawsuits allege lasting damage. That's one reason Douglas Sheff of Boston's Sheff Law Offices hasn't decided whether to take what may be a second Botox lawsuit.

He's reviewing the case of a 4-year-old suffering from spinal muscular atrophy. Plagued by muscle spasms, she was injected with Botox last May to afford her greater mobility. Instead, her condition deteriorated. Once able to feed herself and walk in braces, she can no longer do either and is generally lethargic, he said. "We're waiting to see if this medication, that's supposed to be temporary for its approved uses, wears off," Sheff said.