FDA warns of reactions to alcohol dependence drug

By Susan Heavey

WASHINGTON (Reuters) - Nearly 200 patients given Alkermes Inc's drug Vivitrol for alcohol dependence reported complications from the injection, including abscesses requiring surgical drainage, U.S. health regulators said on Tuesday.

Vivitrol, an extended-release version of the generic drug naltrexone marketed by Cephalon Inc, was approved in 2006 to treat alcohol dependence in patients who show they can abstain from drinking prior to receiving the drug therapy.

Since then, the Food and Drug Administration said it received 196 reports of patients who were given Vivitrol and developed swelling, pain, bleeding and other complications. Sixteen required surgery to drain the injection site or to repair damaged tissue, the FDA said.

The problems appeared to arise when doctors did not properly inject the drug into muscle tissue, Cephalon spokeswoman Candace Steele said.

"We believe it's inadvertent," Steele told Reuters.

Vivitrol is injected into a patient's buttock and doctors need to ensure the needle goes past the fat layer and reaches the gluteal muscles when giving the drug.

How deep the needle needs to go depends on a patient's gender and weight, the FDA said, and women may be at greater risk for reactions "due to typically higher gluteal fat thickness."

Cephalon and the FDA could not say how many of the 196 reports were from women. Most of the 16 patients who required surgery were women, Steele said.

The FDA said doctors should make sure they are giving the injections correctly and with the proper needle. They should also advise patients to monitor the injection site and report worsening reactions.

Among other known side effects with Vivitrol are liver damage, nausea, headaches and diarrhea.

It was unclear how many patients have been given Vivitrol since its approval, but Steele said 70,000 doses have been shipped since 2006. The drug is given monthly and is supposed to be used in conjunction with counseling.

On Nasdaq, shares of Alkermes closed down 44 cents at $16.45, while shares of Cephalon closed up 4 cents to $76.92.

Alkermes did not return calls seeking comment.

(Reporting by Susan Heavey; Editing by Brian Moss, Jeffrey Benkoe and Carol Bishopric)